Case study

By Steven Goldstein, DPM; Basem Halaka, DPM; David Vance, DPM; Jason Weslosky, DPM

History of Present Illness

The patient is a 62 year old male with a 2 year history of thickened, elongated, and yellow discolored nails of the hallux bilateral. The nails appear dystrophic with evidence of subungual debris. The patient does not recall any significant trauma to the nails but does admit to uncomfortable rubbing of the bilateral hallux nails in his shoes. The patient does not have any other contributing medical history.

Work-up

The bilateral nails were debrided and multiple keratogenous samples were sent for analysis (histopathology and PCR). Care was taken to remove debri subungually as well as portions of the proximal nail plate.

Histopathology and Molecular Analysis

Identified in this study were histopathologic features of acute and chronic micro-trauma as well as onychomycosis. Fungal elements were demonstrated with both PAS and GMS stains. Fontana Masson staining was performed as well and was negative for melanin.   PCR testing was performed and was able to identify the organism, a saprophyte of the Fusarium genus.

Green nail syndrome (GNS) is the most common bacterial infection of the nail unit.

Green nail syndrome (GNS) is the most common bacterial infection of the nail unit. Both the upper and lower extremities may be affected in GNS, but is uncommonly reported as a primary cause of onychodystrophy. The causative organism, Pseudomonas aeruginosa, is a gramnegative bacteria which is ubiquitous in nature favoring warm and moist environments with reservoirs in soil, water, plants and animals.

Infection of the nail results in chloronychia as a direct result of the production of pyoverdin and pyocyanin by P. aeruginosa.

By Adi Pajazetovic, DPM, Kalani Parker, DPM

Tinea pedis resistant to treatment may require systemic antifungals

History

A 67-year-old male with no known significant past medical history presented to clinic with an itchy dermatitis like lesion within his left fourth web space. Lesion has been present for an undefined length of time.

Physical Examination

Patient presented with an eczematous/tinea like lesion within the left fourth web space along with maceration to the area.

Diagnostic Testing

A shave biopsy was performed and a submission of a skin fragment measuring 0.3 x 0.3 x 0.1 cm was received to confirm diagnosis of tinea.

Histological Findings

The received specimen was sectioned, and the sections demonstrated scattered neutrophils within the stratum corneum. A periodic Acid Schiff (PAS) stain test was performed, which highlighted septated fungal hyphae, morphologically consistent with dermatophytes within the keratin layer. A PAS is commonly used stain in mycoses diagnosis as it highlights the carbohydrate rich cell wall of fungi¹.

Discussion

Tinea pedis is one of the most common fungal pedal skin infections and is caused by a dermatophyte. It can present as an interdigital manifestation, moccasin patterned, or with inflammatory vesicles, and can often be associated with onychomycosis². The condition generally affects an older population and can be as prevalent as 70% of the population .

The dermatophytes are filamentous fungi in the genera Trichophyton, Microsporum and Epidermophyton. They metabolize and subsist on keratin and infection typically is superficial involving the epidermis. The clinical features include interdigital, hyperkeratotic and vesiculobullous tinea pedis. The interdigital tinea pedis manifests as pruritic, erythematous erosions or scales between the toes, especially in the third and fourth digital interspaces³.  BakoDx now offers a web space DNA test that can help differentiate the cause of the interdigital infections. Infectious agents tested include fungi such as dermatophytes and specific bacterial agents as well. The sampling is a simple shave biopsy of the interdigital lesion. All that is needed is a visible sample of tissue. This easy procedure will aid in the treatment of the infection as it specifies the inciting organism.

Treatment

Tinea pedis rarely causes significant morbidity or mortality, but there is some evidence that it can act as a portal of entry for bacteria causing bacterial cellulitis. Topical antifungal treatment is generally adequate. For extensive infections and especially involving immunocompromised patients, oral therapy may be required. Relapse from inadequate therapy is common and reinfection can reoccur in 10% of cases. Tinea pedis resistant to treatment may require systemic antifungals such as terbinafine, fluconazole, or itraconazole. In cases involving both fungal and bacterial infections, a concomitant antibiotic therapy is justified.

Most superficial cutaneous dermatophyte infections are managed with topical therapy such as azoles, Nystatin, etc. Oral treatment with terbinafine, itraconazole, fluconazole, and griseofulvin is used for recalcitrant infections. The use of combination antifungal and corticosteroids is discouraged as it is unnecessary to achieve cure and increases the risk of steroid induced skin atrophy³.

References:

1: Wang, Michael Z (02/01/2017). “Correlation between histopathologic features and likelihood of identifying superficial dermatophytosis with periodic acid Schiff-diastase staining: a cohort study”. Journal of cutaneous pathology (0303-6987), 44 (2),   152.

2: Usatine, R. P., Smith, M. A., Mayeaux, E. J., & Chumley, H. S. (2019). The color atlas and synopsis of family medicine. New York: McGraw-Hill Education.

3: Goldstein AO, Goldstein BG. Dermatophyte (tinea) infections. UpToDate, 2019.

By Courtney McClurkin, DPM; Andrew Olson, DPM

Molluscum contagiosum can be confused with a variety of different skin pathologies

History

A 25 year old male with no known significant past medical history presents with a pigmented lesion to plantar aspect of his left foot present for an undetermined period of time.

Physical Examination

A raised red and black 3mm lesion is seen on the plantar aspect of left foot.

Diagnostic Testing

A 2mm punch biopsy was performed with clinical concern to rule out melanoma.

Histological Findings

Typical histological features of molluscum contagiosum were identified including molluscum bodies, which are intracytoplasmic eosinophilic structures contained within epidermal cells.  These molluscum bodies become basophilic in the upper part of the epidermis, and are found in high numbers in the horny layer.  There is also a dense polymorphonuclear infiltrate noted adjacent to the epithelium containing the molluscum bodies.

Diagnosis

Molluscum contagiosum

Discussion

Molluscum contagiosum is a skin infection that is caused by a poxvirus.  Transmission of the molluscum contagiosum virus is through contact with an infected person or contaminated surface.  It is most commonly found in young children, but is also notorious for sexual transmission among adults and adolescents.  Transmission rates are generally similar for the immunocompromised.  However, the lesions can be more numerous, appear in atypical locations, and be more resistant to treatment.  The virus incubates for a period of 14 days to 6 months, followed by formation of slowly enlarging, single or multiple lesions.  The lesions most commonly appear as pearly, umbilicated papules.  They can become inflamed and erythematous, causing a “molluscum dermatitis”.  Most cases are self-limiting, though crops of lesions may come and go over the span of months.  There are, however, a plethora of treatment options ranging from physical destruction to systemic treatments.

Clinically, molluscum contagiosum can be confused with a variety of different skin pathologies, including but not limited to: verruca vulgaris, condyloma, nevocellular nevus, basal cell carcinoma, keratoacanthoma, lichen planus, eczema, foreign body granuloma, sarcoidosis, folliculitis, and true epidermal cyst.

Two histologic variants exist.  The pseudocystic variant is distinguished by invagination of colonized epithelium of dilated horn-filled infundibula bordered by a thick epidermis and are filled with compact, thick keratin.  In the polyploid variant, the dermis located beneath molluscum contagiosum has loose collagen fibers, dilated vessels, and inflammatory infiltrate.  Molluscum bodies are the most distinguishing  histologic feature.  These are large cells with cytoplasmic eosinophilic inclusions that contain viral particles.

Associated lesions with molluscum contagiosum are common, including true epidermal cysts, nevocellular nevus, Unna nevus, Clark nevus, soft fibromas, and Kaposi sarcoma.  Abscesses can be associated due to discharge of molluscum bodies to the dermis, followed by release of proinflammatory cytokines and activation of complement pathway.

Treatment

While molluscum contagiosum is typically self-limiting within 6 months, there are treatment options available.  Treatment is initiated in order to alleviate discomfort produced by itchy or painful lesions, for cosmetic reasons, to prevent spread of lesions, as well as to prevent trauma, scarring, and secondary infection of lesions.

Surgical treatments include: cryotherapy, curettage, punch biopsy, manual excision, electric cauterization, and laser therapy.

Topical treatments include: acidified nitrite, adapalene, Australian lemon myrtle oil, benzoyl peroxide, bromogeramine, cantharidin, cidofovir, diphencyprone, griseofulvin, honey, hydrogen peroxide, imiquimod, iodine, phenol, podophylotoxin (HIV patients), potassium hydroxide, salicylic acid, tea tree oil, and tretinoin.

Systemic treatments include cimetidine, griseofulvin, and cidofovir (in HIV-infected patients).

References:

Cribier, B., Y. Scrivener, and E. Grosshans. Molluscum contagiosum: histologic patterns and associated lesions. The American Journal of Dermatopathology 23(2): 99-103 (2001).

Mancini, A.J. and A. Shani-Adir. Other Viral Diseases. Dermatology 3^rd ed. (2012): p. 1358-59.

Van der Wouden, J.C., et. al. Interventions for cutaneous molluscum contagiosum (review). Cochrane Database of Systematic Reviews Issue 5, Art. No.: CD004767 (2017).

By Desiree Dalcherone, DPM; Laura Fernandez, DPM; Pooja Srivastava, DPM

Lesions are usually asymptomatic, but some cases might present with itching and pain

History

Patient is a 29 year old male with past medical history of Crohn’s disease, presenting with a one year history of progressively worsening, painful nodules to his bilateral legs and feet.

A punch biopsy of skin was taken from the nodule present to the patient’s plantar-medial left hallux.

Physical Examination

Multiple nodules were present on bilateral legs and feet.

Histologic Findings

Sections show an intense neutrophilic infiltrate with associated nuclear dust and interstitial eosinophils at all levels of the reticular dermis. The deeper regions of the reticular dermis show significant fibrosis in association with the infiltrate present. Active neutrophilic vasculitis is felt to signify a late stage process.  Gomori methenamine silver stain fails to demonstrate fungal elements.  AFB stain fails to demonstrate mycobacterial organisms.

Diagnosis

Erythema Elevatum Diutinum (EED)

Discussion

Erythema elevatum diutinum is categorized as a chronic fibrosing leukocytoclastic vasculitis usually occurring in patients in their thirties to fifties, earlier in HIV. The lesions might present as orange to yellow plaques, or red to purple papules and nodules measuring approximately up to 1 cm. They are usually found in extensor surfaces in the back of the hands or fingers, wrists, elbows, knees, ankles, and toes. The lesions are usually asymptomatic, but some cases might present with itching and pain, usually made worse with cold environments.

Inflammatory bowel disease (Crohn’s disease and ulcerative colitis) has been associated with the onset of erythema elevatum diutinum.  EED has also been reported in patients with Celiac disease and resolved with a gluten-free diet.

Other reported associations include rheumatoid arthritis, granulomatosis with polyangiitis, relapsing polychondritis, pyoderma gangrenosum, Sweet syndrome, cutaneous lupus erythematosus, nodular scleritis and panuveitis, Hashimoto thyroiditis, juvenile idiopathic arthritis, Sjögren syndrome, dermatomyositis.  EED can be associated with systemic infections, including streptococcal infections, HIV, hepatitis B, tuberculosis, and syphilis

ANCAs (60% IgA and 33% IgG) are found in EED, however, other ANCA-positive vasculitides such as granulomatosis with polyangiitis and microscopic polyangiitis, do not present with these lesions.

Differential diagnosis includes granuloma faciale which also involves the dermis. Granuloma faciale, however, shows mostly eosinophils whereas EED shoes more neutrophils. Sweet Syndrome is another form of neutrophilic disease with rapid onset of tender and erythematous plaques and nodules, but it is differentiated by the lack of leukocytoclastic vasculitis.

Treatment

Since EED is generally associated with an underlying systemic disease, such as hematologic conditions, autoimmune disease, chronic infections, HIV- it is imperative to control the underlying cause as well as directly targeting the lesions.

In this particular case, the patient’s EED is likely associated to Crohn’s Disease. Treatment for Crohn’s Disease include anti-inflammatory drugs such as aminosalicyclates, corticosteroids, sulfasalazine and azathioprine. Aminosalicyclates are generally first-line treatment, and suppress inflammation to the intestine. Antibiotics such as tetracyclines and sulfa drugs can also be given adjunctively to kill bacteria in certain areas of the bowel, and also decrease inflammation.

Focusing on the nodules themselves, oral Dapsone is the most common drug given, with a response rate of up to 80%. Dapsone works by inhibiting neutrophil chemotaxis. Second-line drug treatments include corticosteroids, colchicine, and methotrexate.

Surgical excision of the nodules in a progressed disease state has also been found to provide symptomatic relief, however since EED nodules are quite recurrent, multiple surgeries are needed to keep the patient nodule-free.

References:

Rinard, J., R. Mahabir, J. Greene, and P. Grothaus. Successful surgical treatment of advanced erythema elevatum diutinum. Can J Plast Surg 18(1): 28-30 (2010).

Wollina, U., C. Kronert, A. Koch, J. Schonlebe, A. Vojvodic, T. Lotti. Erythema elevatum diutinum – two case reports, two different clinical presentations, and a short literature review. Global dermatology. 18(7):3039-3042 (2019).

Crohn’s Disease. Harvard Health Publishing : Harvard Medical School. https://www.health.harvard.edu/a_to_z/crohns-disease-a-to-z. November 2018.

Calonje E, McKee PH, undefined undefined undefined. Vascular Diseases. In: McKees Pathology of the Skin: with Clinical Correlations; 5th ed. Philadelphia, PA: Elsevier, Saunders; 2020:714-770

James WD, Elston DM, Treat JR, Andrews GC, undefined undefined undefined. In: Andrews Diseases of the Skin: Clinical Dermatology. 13th ed. Elsevier; 2020:813-861

Sandhu JK, Albrecht J, Agnihotri G, Tsoukas MM. Erythema elevatum et diutinum as a systemic disease. Clinics in Dermatology. 2019; 37(6): 679-683.

By Morgan Baxter, DPM, Aron Block, DPM, Lillian Youhkana, DPM

Blastomycosis is a type of fungal infection that can be acquired from inhaling fungal spores

History

A 53 year old healthy male presents to clinic with concerns of a rash involving raised bumps for about a month. He thought it was a cluster of warts, but has not had any relief with over the counter topical medications. He does mention that about a month ago, he was raking leaves barefoot. The bumps are not painful but have started to leak and have not gone away. He resides in Ohio near Lake Erie.

A punch biopsy of a representative lesion was submitted.

Histologic findings:

Diagnosis

Blastomycosis

Differential Diagnosis

Other cutaneous infections can mimic cutaneous blastomycosis including other endemic mycosis such as histoplasmosis and coccidioidomycosis. It has been found that cutaneous blastomycosis may very closely resemble pyoderma gangrenosum or keratoacantoma or malignancies such as basal cell carcinoma or squamous cell carcinoma. For proper diagnosis a skin biopsy is vital in differentiating blastomycosis infection from these other diseases.

Discussion

Blastomycosis is a type of fungal infection that can be acquired from inhaling fungal spores from the air.   It is found in the United States and Canada and is concentrated in the Ohio and Mississippi river valleys and the Great Lakes region.  Blastomycosis is typically found in soil and decaying organic matter. It manifests as a primary lung infection in the majority of cases.  In individuals with weakened immune systems, the infection can spread to other areas of the body such as the skin. Following pneumonia, cutaneous lesions are the next most common manifestation of blastomycosis. The skin lesions are either verrucous or ulcerative. Bone, prostatic and CNS blastomycosis are also fairly common presentations of this infection. The disease is often misdiagnosed, particularly as malignancy. Search for the organism by microscopy and culture should be considered, even in those with a classic presentation of other illnesses. Most people with blastomycosis will need treatment with prescription antifungal medications. Depending on the severity of the infection, the course of treatment can range from six months to a year. Mild and moderate fungal infections involving the skin and lungs are best treated with Itraconazole. Amphotericin B should be used in severe infections involving the lungs. In conclusion, a thorough history including a geographical location is imperative to help make the accurate diagnosis of a blastomycosis infection.

References:

Chapman SW, Dismukes WE, Proia LA, Bradsher RW, Pappas PG, et al. (2008) Clinical practice guidelines for the management of blastomycosis: 2008 update by the Infectious Diseases Society of America. Clinical Infectious Diseases 46: 1801–1812

Larson DM, Eckman MR, Alber RL, Goldschmidt VG. Primary cutaneous (inoculation) blastomycosis: an occupational hazard to pathologist. Am J Clinc Pathol. 1983;79(2):253–255.

McBride, J. A., Gauthier, G. M., & Klein, B. S. (2017). Clinical Manifestations and Treatment of Blastomycosis. Clinics in chest medicine, 38(3), 435–449. doi:10.1016/j.ccm.2017.04.006

Saccente M, Woods GL. Clinical and laboratory update on blastomycosis. Clin Microbiol Rev. 2010

Smith JA, Riddell J, IV, Kauffman CA. Cutaneous manifestations of endemic mycoses. Curr Infect Dis Rep. 2013;15(5):440–449

CLINICAL STUDY

DNA-based detection for onychomycosis correlates better to
histopathology than does fungal culture

Introduction

As a general rule, the podiatic profession is notorious for its underutilization of cutaneous and soft tissue biopsy techniques. In some instances, such under-use may be attributed to trepidation stemming from a lack of familiarity with the biopsy techniques themselves; however, I believe this is not the preeminent cause. In my experience, the most common reason that many podiatric clinicians don’t use biopsy techniques to their fullest is a degree of insecurity regarding when to use witch biopsy and what to do with them once the biopsy has been performed. In most offices, the support staff is ill prepared to offer much in the way of guidance, leaving the clinicians on their own.

The purpose of this report is to summarize the indication for biopsy, when each technique is most appropriate, and the method of fixation that is required for laboratory examination.

Biopsy Techniques

Not uncommonly, clinicians create unnecessary limitations with respect to how they should use biopsies and what constitutes a ‘biopsy’ itself. We can easily fall into a pattern of thinking whereby we equate the word ‘biopsy’ with a 3:1 ellipse or limit the word biopsy to only those specimens taken by punch technique. Either misimpression might result in under-utilization and the latter would likely result in suboptimal sampling in more than half of the cases in which a biopsy is being used. Simply stated, anytime tissue is taken to obtain a diagnosis through histopathologic analysis, a biopsy has been performed. Common techniques include, but are not limited to, punch biopsy, shave biopsy, saucerization (a form of shave biopsy), curettage, core needle, and aspiration biopsy.

Punch biopsy (CPT 11100 initial, CPT 11101 subsequent) is a common technique used to sample conditions that 1) are too large to be shaven or 2) have a deep dermal component (requiring deeper sampling). This is the ideal technique for sampling all forms of dermatitis; however, this is far from where its utility ends. Punches may be used to sample suspected vasculitis, ulcers, large pigmented lesions (those too large to be shaven), and other large suspected neoplasms (those that are greater than 1cm in diameter). Three-millimeter punches are used for epidermal nerve fiber density testing (Figure 1).

Small punches (2mm) also may be ideal for plantar verrucous lesions. Because this technique samples the full thickness of such plantar lesions, it allows dermatopathologists to accurately discriminate between genuine verrucae and clinically identical verrucous carcinomas. In sum, punch biopsies are ideal when a small part of a much larger lesion is submitted for histopathology.

Standard shave biopsies (CPT 11300 series) are used much more commonly in dermatologic practices than are punches. In fact, the combination of standard shaves and saucerizations) represents the overwhelming majority of biopsies performed by dermatologists. This technique uses a scalpel to “shave off” a lesion of concern (Figure 2), leaving a shallow iatrogenic ulceration in its wake. Shave biopsies contrast sharply with punch biopsies in many respects. Shaves do not routinely sample the deep dermis, rather, they typically extend only to the depth of the superficial dermis. In addition, where punches are relatively narrow (most punches are 2-4mm in diameter), shaves often encompass a broad sample of superficial skin (often 1cm or greater in width).

Shave technique is the ideal sampling method for unexplained papules (elevated lesions measuring 5mm or less in diameter), and can be used for macules (flat lesions measuring less than 1cm in diameter). Usually a standard shave is performed when the lesion in question appears superficial and/or exophytic (outward growing).

Saucerization (CPT 11300 series) is a technique that is closely related to a standard shave biopsy. In fact, saucerization has many of the same indications and is coded identically. This technique uses a bendable blade, not dissimilar to a Gillette razor blade, to “scoop out” the tissue of concern (Figure 3).  Where standard shaves are ideal for superficial and/or exophytic lesions, saucerizations are better for flat or endophytic (inward growing) lesions. Conceptually, this technique is thought of as a more aggressive method of sampling and thus can lend itself more to complete excision than can shave.

Curettage (CPT 11100 unless completely excised) is a less common sampling method than are the previously described techniques; however, it remains a viable biopsy technique for many dermatologists. Curettage uses a dermal curette to scrape the surface of the skin to obtain the desired tissue sample (Figure 4). The disadvantage of curettage is largely related to how difficult these specimens may be to histopathologically examine. Inherent in the mechanics of this technique is the fragmentation of the sample. This may make the tissue impossible to correctly orient, which can complicate its histopathologic examination.

Core needle biopsy is an ideal method of characterizing more deeply seated masses. This technique is perfect for investigating tumors of the soft tissue. Essentially any mass that falls into the differential diagnosis with a lipoma or ganglion could be sampled using c o r e n e e d l e technique. Makers of core needles include Temno ™ and Trucut™ (Figure 5).

Core needles a r e h o l l o w , large gauge needles designed to withdraw thin columns of tissue from within the mass in question. The technique is easy to perform and is highly effective. To obtain tissue using core needle biopsy, the skin overlying the mass is lanced and the instrument is inserted to abut the mass in question. Depending on the size of the mass, the biopsy instrument is set by the clinician to sample to a desired depth using a spring loaded mechanism. The device is discharged and the sample is obtained. This is usually repeated into the masses’ various quadrants.

Needle aspiration biopsy (CPT 10021 without imaging guidance or 10022 with imaging) is slightly less invasive than is core needle biopsy but has essentially the same indications. This technique uses a large gauge hypodermic needle and a large syringe to sample fluid and/or cells from deeply seated masses (Figure 6).

The secret of core needle biopsy is to create a vacuum once the needle has been introduced into the mass and to maintain the vacuum throughout the remaining aspiration procedure. The needle should be redirected into each of the 4 quadrants twice, without releasing the plunger and without completely removing the needle from the mass. Any fluid that is obtained may be expelled into fixative. If grossly perceivable tissue is not obtained, fixative should be drawn up into the syringe and then squirted back into the specimen container . This functions to flush any of the potentially neoplastic cells out of the aspiration needle.

Biopsy Indications The indications for biopsy vary depending on the nature of the lesion in question. As a general rule, there are three categories of indications for biopsy: 1) atypically appearing lesions, 2) typically appearing lesions which behave in an atypical fashion, 3) progressive, longstanding lesions or conditions which cannot be adequately explained. For inflammatory conditions / dermatitis, the indications are predominantly related to the patient’s perception of the condition. Indications include, but are not limited to: 1) significant patient frustration, 2) severe symptomatology, 3) recalcitrance and 4) those cases that have entirely nonspecific clinical findings. In contrast, the indications for biopsy in relation to pigmented lesions of the skin are almost entirely related to the clinician’s impression of the lesion in question. Asymmetry of pigment, asymmetry of configuration, irregular outlines, and a diameter of greater than 6mm all represent indications for biopsy.off” the skin surface.

Pigmented lesions include all those lesions that might fall within the differential diagnosis of a pigmented malignant melanoma. This differential diagnosis includes lesions as disparate as solar lentigos, melanocytic nevi, seborrheic keratoses, tinea nigra, and talon noir. The criteria which should lead to the consideration of biopsy within this class of lesions are: 1) asymmetry of configuration, 2) asymmetry or variegation of color, 3) irregular outlines, or 4) size greater than 6mm in diameter . The symmetry of configuration should be assessed in 3 dimensions. As such, if the lesion is bisected in a plane that is perpendicular to the skin, each half should be identical, not just with regard t o i t s s h a p e along the skin’s surface, but also its elevations and depressions. It should also be stated that newly arising or changing lesions greater than 6mm in diameter in adults represent an absolute indication for biopsy, not a relative one. The indications for biopsy in relation to non-pigmented tumors of the skin are less well defined and lend themselves to more subjectivity than those for pigmented lesions. For the most part , papules, nodules, and plaques that cannot be effectively explained should receive prompt biopsy, or at minimum, clinical follow-up. Lesions that do not show evidence of resolution or involution should be sampled. An important point here is that simply harboring a papule or nodule that cannot be explained is of itself “atypical”.

Frank evidence of malignancy is not ne c e s s a ry to prompt a biopsy. In keeping with this theme, biopsies should be considered on all ulcers that cannot be adequately explained, and those that persist despite appropriately targeted therapy. Additional miscellaneous biopsy indications include: verrucous lesions in persons over 40 years of age, tumors of all types that show recalcitrance, and pyogenic granulomata in persons over 40 (Figure 7).

The soft tissue includes all the non-epithelial, non-skeletal, and non-visceral tissue of the body. This includes smooth muscle, skeletal muscle, adipose tissue, fibrous tissue, and peripheral neural tissue, amongst others. The indications related to biopsying tumors of the soft tissue are complicated by three facts. Foremost, tumors of the soft tissue are usually masked by the overlying skin and fascia, making their clinical features entirely nonspecific. Secondly, the foot boasts a large number of benign soft tissue masses that aren’t particularly common elsewhere within the body. Ganglia, for instance, are largely limited to the hands and feet. The same is true of digital mucous cysts. Finally, podiatric clinicians may be unaware of core needle and aspiration biopsy techniques, instead relying on more invasive open biopsies or complete excisions. This constellation of facts has the net result of diminishing the number of biopsies performed by podiatric clinicians and lowering their index of suspicion when dealing with soft tissue masses in the foot. In many instances, diagnostic procedures are delayed, resulting in tumor progression and a worsened prognosis. As a general rule, progressive soft tissue masses that cannot be adequately explained should be investigated. The dimension that is often given in the orthopedic oncology literature as an absolute indication for biopsy is 5cm; however, this is of little value when dealing with masses in the foot because of their easy accessibility. Tumors become evident at a much smaller size in the foot and thus should be investigated. Simply having a cystic component does not exclude the possibility of neoplasia as high grade sarcomas and many adnexal carcinomas can cavitate . Similarly, a mass’s tendency toward trans-illumination does not equate with benignancy .Many cystic and myxoid malignancies will trans-illuminate to some extent (Figure 8).

Imaging may be helpful; however, as many clinicians will acknowledge, this rarely provides a definitive opinion with regard to a mass’s potential biologic behavior. Early investigations may be aided by needle aspipapule ration biopsy. This technique has the advantage of being minimally invasive and well tolerated. This makes it an easy technique to perform as a purely investigative procedure, allowing clinicians to rule in or out the obvious diagnoses. Masses that fail to produce an aspirate(“dry taps”) should be taken for open biopsy, the most common form of which is core needle biopsy. When the aspiration of a mass produces fluid of an unusual consistency, it should be sent for cytopathologic analysis. Initial aspiration biopsies, which produce clear mucinous fluid typical of a ganglion, may be sent for analysis at the clinician’s discretion; however, subsequent aspirations performed on recalcitrant lesions must be analyzed.

Technique Selection

Large plaques, patches

The principles for technique selection are fairly rudimentary with few exceptions. Dermatitides and other conditions of the skin, which are too broad to “shave off”, are instead punched. Inflammatory conditions that would most often be punched include psoriasis, eczematous (nummular) dermatitis, lichen planus, granuloma annulare, and all conditions that might fall into their differential diagnosis. Neoplasms also may be punched in some instances. Squamous cell carcinoma in-situ may present as a plaque and thus warrant punch biopsy. Similarly,melanoma insitu may present as a broad patch or plaque that is more conducive to punch technique (Figure 9).

In general terms, when a small part of a patch or plaque is sampled for histopathology, punch technique is the technique of choice. One exception to the general rule that only large lesions are punched, and those that are small are shaven, involves verrucous lesions on the plantar surface. Because keratotic lesions iagof the plantar surface tend to be endophytic, shaves may not sample deep enough to obtain diagnostic tissue. For such lesions, punch technique will better allow the dermatopathologist to distinguish between lesions that may mimic each other superficially. An example of two lesions that might be identical superficially, and one that has caught me unsuspecting, are those of superficial palmoplantar wart and verrucous carcinoma.

Ulcers

Ulcers may be sampled by several methods depending largely on their clinical setting. Ulcers may be either neoplastic (carcinoma or melanoma) (Figure 10) or inflammatory (stasis or vasculitis) in etiology.

In most instances punches are ideal in either setting; however, exceptions exist. When punches are used, their ideal number and placement might vary. When characterizing suspected neoplastic ulcerations, a single punch may be all that is needed to obtain a diagnosis; however, in such conditions two are better than one to ensure appropriate sampling. In this clinical setting, one central punch and one upon the mounded flesh at the periphery of the ulcer is usually adequate. Usually relatively small punches are adequate. Alternatively, clinicians could potentially use a dermal curette or scalpel to obtain viable tissue from the ulcer’s base and proud peripheral flesh. In contrast to neoplastic ulcers, to characterize inflammatory ulcers, only punch biopsy techniques are recommended. In most cases, the cause of the ulceration in question lies deep within the dermis, far below the reaches of a superficial shave biopsy. For most conditions at least two punches are recommended, one central and one over the epidermal lip at the periphery of the ulcer. One exception to this recommendation would be for suspected vasculitis. In this context, multiple random punches are required over the ulcer base. In the case of vasculitis, the objective is to sample multiple locations along the ulcerbase in hopes of finding an affected vessel within the underlying dermis. Because this is a search that is reminiscent of depth charges seeking out an underlying submarine, there is an advantage to using punches of 3mm or larger.

Advanced superficial tumors

In most cases, the objective when biopsying advanced superficial tumors is not to rule in or out malignancy as much as it is to define the type of malignancy (Figure 11).

This allows the clinicians to know whether they should deal with the neoplasm in question themselves, or whether the patient should be referred out to an alternative subspecialist. In addition, for those cases that are to be referred out, the precise diagnosis will provide the podiatric physician with the information s/he needs to refer the patient out to the appropriate discipline. In this setting, a punch biopsy will allow the clinician diagofnostic tissue without complicating a future excision or sentinel node biopsy.

Soft tissue/subcutaneous masses

Deep soft tissue masses and those lesions which clinically resemble them were discussed briefly above. To elaborate, there are four methods of sampling masses of the soft tissue: 1) excisional biopsy, 2) incisional open biopsy, 3) core needle biopsy, 4) needle aspiration biopsy. Excisional biopsy should be reserved for bases that are small and proven to be benign.

The accidental excision of an unsuspected sarcoma could have prognostic significance ranging from loss of limb to loss of life. Incisional open biopsy carries with it the advantage that a larger volume of tissue is removed, which may be useful for testing purposes. However, due to the high risk of wound site complications, and poor tumor sampling, this technique is usually initially deferred. The most common technique for sampling soft tissue masses in the extremities is core needle biopsy. This technique allows the surgeon to harvest cores of tissue from various sites within the mass in question and has a very low complication rate. The most common core needles for this indication are Tru-cut™ and Tenmo™. Needle aspiration is an excellent initial minimally invasive technique to help verify benign diagnoses (ganglia), and to help guide clinicians to more invasive biopsy techniques when indicated.

Papules or macules

Papules and macules are by definition less than 1cm in greatest dimension (Figure 12). Because of their small size they can often be removed entirely, or almost entirely, using a standard shave technique or saucerization. By removing the preponderance of the lesion in question for histopathologic analysis, the dermatopathologist will be far less likely to be fooled by inadequate sampling. Papules are small elevations over the skin surface which measure less than 5mm (1cm in some texts). Because these primary lesions are elevated, they are readily shaved flush using a 15 or 10 blade. As papules become small nodules, they tend to become less superficial in extent. For relatively small nodules that seem to have a component that extends deeper into the dermis, or for macules (small flat alterations in pigment), saucerization is often a preferred biopsy technique. Because saucerization uses a metal blade that is bent to form an arch, this techniqueallows the physician to “scoop out” the biopsy site. The curve of the blade allows for better control when sampling lesions that lie deep to the skin surface.

Post-Biopsy Specimen Handling

The correct handing of the biopsy specimen, after the procedure has been performed, could make the difference between obtaining a rapid diagnosis and the performance of a wasted procedure. The overwhelming majority of tissue that is sampled using biopsy techniques should be fixed in formalin (10% formaldehyde); however, exceptions exist. The exceptions are as follows: Gout: When gout is suspected, the specimen should be placed in dehydrated alcohol. Alcohol preserves the monosodium urate crystals for crystal analysis and review under polarized light. Regardless of the biopsy method, alcohol is preferred unless the sample is kept fresh in a sterile container or a slide preparation is made in the office setting. Remember formalin contains 90% water, and water dissolves monosodiumu rate crystals.

Epidermal nerve fiber density testing: Formalin fixative is an excellent preservative for routine histopathology; however, it has deleterious effects on tissue taken for epidermal nerve fiber density analysis (degenerates intra-epidermal nerves and blocks important antibody binding sites on their surface). There are two potential fixatives that can be used for this test, each typically distributed only by labs specializing in this test (see www.bakopathology.com for more information).

Aspirations: Aspiration biopsies are ideally preserved in cytologic fixative. Formalin may dull some of the fine nuclear features that aid in diagnoses. Alternatively, slide preparations may be made in the office setting when clinicians have experience in this technique. We have made important diagnoses on aspirates that were received in formalin fixative; however, clinicians should know that this fixative has some limitations.

Cultures: Samples taken for microbiologic culture are not typically considered “biopsies” in the same sense as those procedures herein discussed and would not be billed in the same manner. Such samples are mentioned here only to stress that

tissue taken for culture should be kept fresh and not contaminated. This may be done using appropriate tissue swabs, agar slants, or sterile cups. There is a roughly 3 day window within which such specimens fixashould be plated after which bacterial cultures begin to be compromised. Formalin and alcohol will preserve tissue for histopathologic analysis, but it will kill all living cells within the sample.

Most biopsies are small, either in width, depth, or both. Their small size makes them particularly susceptible to air dry artifact. Once samples that are to be analyzed histopathologically are placed in formalin fixative,they are indefinitely preserved. The case is similar with alcohol. Punch biopsies taken for epidermal nerve fiber density are unique in that they can be left in their special fixative (not formalin) for only 24 hours before the quality of the sample will begin to erode. For this reason, the specimen is typically retained within the clinical practice for 12-24 hours as it is being fixed, rinsed, and then placed in cryoprotectant for shipping.

Conclusion

In summary, there are a host of biopsy techniques within the armamentarium of today’s podiatric surgeon, each of which has its own indications. Many of the indications for these procedures are absolute and leave room for subjectivity only in unique circumstances. Once the indication has been acknowledged, the most appropriate biopsy technique should be chosen and performed. The product of most biopsies will be small ,making it necessary to quickly transfer the specimen into the correct fixasamtive. Formalin is usually the fixative of choice but exceptions do exist. Finally, although there is always an “ideal” technique for a particular indication, the fundamental principle is that “making the diagnosis trumps all else”. As physicians, we’ll virtually never do harm by doing a less than ideal procedure; however, in some instances, we will ensure harm by doing nothing at all.

Many clinicians rely exclusively on clinical acumen when determining how to manage chronic wounds. Though an ulcer’s clinical features may be fairly indicative of its etiology, in some instances, such is not the case. Even among the most characteristic‐appearing ulcerations, masqueraders do exist. Ruling out the possibility of an unsuspected neoplastic or inflammatory condition could be necessary for the successful management of chronic wounds. In this context, cutaneous biopsy techniques may be invaluable; however, their utility does not necessarily end here.

There are three common clinical settings in which a biopsy may be used in the management of a chronic wound. Clinicians may use histopathology to 1) confirm a clinically suspected diagnosis at the outset of care, to 2) rule out a mimic in cases where a wound is showing recalcitrance or unusual progression, to 3) assess for an underlying predisposing condition independent of the ulceration, or to 4) assess for compounding feature, such as an excessive bacterial burden.

Because the clinical presentation of cutaneous  ulcerations may be virtually pathognomonic of a particular etiology, the first of these scenarios should not always give rise to a biopsy; however, in some instances, confirmation is warranted. In a minority of cases, the clinical manifestations that surround an ulceration are entirely nonspecific and a biopsy is indicated prior to the initiation of medical care.

For wounds that appear characteristic of a particular etiology, biopsies are usually not initially necessary; however, as a rule of thumb, biopsies should be considered for all ulcers that cannot be readily explained or fail to show improvement after 2 months of treatment. In instances such as this, biopsies are being used to verify that the implemented therapeutic regimen is appropriate.

Delays in the diagnosis of some mimics may be medicolegally treacherous. For instance, malignant melanoma, particularly amelanotic variants, may create ulcers that are virtually identical to non‐neoplastic ulcers. Delays in this diagnosis may have serious implications with regard to the affected patient’s outcome. Simply stated, the failure to reassess ones differential diagnosis in cases where ulcerations show unusual clinical behavior, or recalcitrance, may be a direct cause of increased morbidity.

An additional clinical setting where a biopsy might prove useful in the management of chronic wounds, involves patients with suspected neuropathy as a predisposing condition. With a 3mm punch biopsy of skin, taken for 10 cm above the lateral malleolus, physicians may qualify and quantify the presence of small fiber neuropathy.

Degenerative changes among the intra‐epidermal nerves, further may be predictive of the future onset of small fiber neuropathy. Though this examination uses a simple 3mm punch of skin, there are differences in the handling of biopsies taken for this purpose. Most important among these differences are that punches taken for epidermal nerve fiber density testing require a specialized fixative that must be requested from the lab, and care must be taken to avoid crushing the surface epithelium when removing the tissue from the biopsy site.

Formalin fixative renders the biopsies useless for small fiber analysis. In most instances, the biopsy technique of choice for verifying the cause of an ulceration, assessing for neoplastic and non‐neoplastic mimics, and characterizing predisposing conditions, is a punch biopsy. In the initial two settings, a central and peripheral 3mm punch is usually

Needle aspiration biopsy is amongst the most underutilized diagnostic procedures of those available.

This technique may be effectively used to rule out high‐grade malignancies when faced with nonspecific subcutaneous masses, in particular, those masses that resemble ganglion cysts.

I once had three different medico‐legal cases under consultative review at one time, all of which were centered on patients who had non‐specific ganglion‐like masses.

In each instance, the patient actually harbored a high‐grade sarcoma, and in each case, they were followed into their grave by their clinician with the errant diagnosis of “ganglion”.

It is not overtly surprising that neoplasms masquerading as ganglion cysts may fool clinicians. For instance, roughly 70% of all the soft tissue masses in the foot are ganglia.

This may lull clinicians into complacency, believing that all hoof sounds are derived from horses, and that zebras don’t exist. In 1999, Scully et al. of Duke University summarized their experience with synovial sarcoma primary to the foot.

In their series of 14 cases, 8 patients were followed for extended periods of time with the incorrect diagnosis of ganglion cyst. In our series of 401 pedal soft tissue tumors assembled at Memorial Sloan‐Kettering Cancer Center we had 8 synovial sarcomas. Amongst these 8 cases, 2 patients saw their diagnosis dramatically delayed because of the errant diagnosis of “ganglion”.

Needle aspiration differs somewhat from most other biopsy techniques in that it provides the pathologist with cells and tiny tissue fragments to review, rather than large pieces of tissue. In other words, pathologists are not able to review a lesions overall architecture and pattern of growth. Instead, they must extrapolate the necessary diagnostic data from the appearance of individual cells.

Because the material at the pathologists’ disposal may be somewhat limited, cytopathology can be somewhat less specific than histopathology. In this vein, the pathology reports derived from aspiration specimens typically provide basic, though highly significant information such as: “malignant cells not identified”, “atypical cells identified”, or “malignant cells identified”.

Though vague in comparison to the diagnoses rendered after histopathologic analysis, these techniques may provide invaluable information in the management of patients with non‐specific subcutaneous masses, by ruling out the presence of high‐grade malignancies.

The purpose of needle aspiration biopsy is to harvest cells and small pieces of tissue from lesions in question.

To accomplish this, clinicians should use large (18 gauge) needles, and syringes that will produce high vacuum pressure (10cc or larger).

An anesthetic wheal may be raised at the needle entry site. The needle is placed in the mass percutaneously, and the plunger is drawn back to create a vacuum, which is maintained through the procedure.

The needle is partially withdrawn, and then redirected into each quadrant while maintaining the vacuum.

Once each quadrant has been sampled, the vacuum is released, and the needle is removed. If fluid is obtained, it may be put directly into fixative. If no aspirate is apparent, fixative should be drawn up into the syringe, and then the collective contents is returned to the specimen jar.