Annular atrophic plaque over the arm.

Sir,

A 60-year-old male farmer, a resident of eastern Uttar Pradesh, India presented with a complaint of gradually increasing skin lesion over his right arm of six months duration. He had a history of blunt trauma over that site, 3 months prior to the onset of the lesion. The lesion initially started as a skin-colored papule, which gradually progressed to the present size. There was no significant past medical history and the patient had not taken any prior topical or systemic treatment. His examination revealed a single erythematous annular plaque measuring 6 × 5 cm over flexor aspect of his right forearm. The plaque had well-defined, irregular margins with atrophy and hair loss in the centre without any evidence of black dots on its surface [Figure 1]. Diascopy was negative for apple jelly nodules. The sensory, motor, neural, and systemic examination were not contributory. Skin biopsy was performed with borderline tuberculoid leprosy, lupus vulgaris, and subcutaneous mycosis as differential diagnoses. Histopathological examination from infiltrated margin of plaque showed hyperkeratosis and irregular acanthosis. The reticular dermis had numerous microabscesses and a granulomatous infiltrate. A fair number of brown, rounds, thick-walled fungal spores were seen in the microabscesses and within the giant cells of neutrophilic granulomas [Figure 2]. In view of these biopsy findings a diagnosis of chromoblastomycosis was concluded. Fungal culture on Sabouraud media was performed on two occasions; however it did not yield any growth and further identification of the causative agent could not be performed due to financial constraints. His hematological, biochemical, and serological examination for Human Immunodeficiency Virus (1 and 2) did not yield any abnormality. The patient was treated with tablet terbinafine 250 mg twice daily for 3 months with complete resolution of the lesion and no recurrence at two year follow up [Figure 3]. The patient did not consent for a post-treatment histopathological examination.

Figure 1

Erythematous annular plaque measuring 6 × 5 cm over flexor aspect of right forearm with well-defined irregular margins, atrophy, and hair loss in the center

Figure 2

Histopathological examination (hematoxylin and eosin staining) showing hyperkeratosis, irregular acanthosis, and numerous microabscesses and granulomatous infiltrate in reticular dermis (H and E, ×100). Brown, round, thick-walled structures (sclerotic/medlar bodies) seen in the microabscesses and within the giant cells of neutrophilic granulomas in inset. (H and E, ×200)

Figure 3

Complete resolution of lesion after 3 months of treatment

Chromoblastomycosis is a chronic granulomatous fungal infection affecting skin and subcutaneous tissue.[12] Majority of cases are from tropical and subtropical regions. In India, it is mainly reported from sub-Himalayan belt, eastern and western coastal regions.[23] Most of the affected patients are agriculturist males (70%) of age between 30 and 50 years.[1] The lesions are commonly seen over lower extremities, with a history of preceding trauma with vegetating matter, leading to inoculation of dematiaceous moulds in tissue. It can occur in both immunocompetent and immunocompromised individuals (renal, pancreatic transplant patients, patients receiving corticosteroids/cyclosporine, diabetics).[1] The most common agent is Fonsecaea pedrosoi. Other less common ones include Fonsecaea compacta, Phialophora verrucosa, Cladphialophora carrionii, and Rhinocladiella aquaspersa.[1] Clinical presentation is variable and the lesions are classified into five different types: Nodular, plaque, tumoral, cicatricial, and verrucous.[2] Out of these nodular, tumoral, and verrucous types are more frequent than the cicatricial and plaque-type.[2] However, ulceronodular or nodular lesions in sporotrichoid fashion and rarely fistulous lesion may be seen.[12] Cicatricial type is characterized by non-elevated lesions that enlarge by peripheral extension, atrophic scarring with central healing and annular, arciform, or serpiginous outline.[2] Cutaneous lesion in our patient also had similar features. The important differential diagnoses include subcutaneous mycoses, bacterial infections (leprosy, nocardiosis), mycobacterial infections (tuberculosis verrucosa cutis, lupus vulgaris), and parasitic infections (leishmaniasis and rhinosporidiosis). It should also be differentiated from noninfectious diseases such as planoepithelial carcinoma, psoriasis, sarcoidosis, or lupus erythematous.[2345] The diagnosis of chromoblastomycosis is done with the help of microscopy, culture, histopathology/cytological, and molecular techniques.[1234] Direct microscopic examination of skin scraping/crust with 10% KOH, especially calcofluor and other fluorochromes stains demonstrate thick-walled round fungal sclerotic bodies. The confirmation of diagnosis and further speciation can be done by culture on Sabouraud's dextrose agar containing antimicrobials incubated at 25°C, which produces colony of melanized fungus over 2–4 weeks.[123] On histopathology, pseudoepitheliomatous hyperplasia, intraepidermal microabscesses, and lichenoid granulomatous inflammation are seen throughout dermis. The inflammatory infiltrate comprises of lymphocytes, plasma cells, histiocytes, eosinophils, and giant cells. Fungal elements are seen as pigmented sclerotic bodies with vertical and horizontal cross walls (5–12 µm) known as medlar or copper penny bodies, diagnostic of chromoblastomycosis,[123] as seen in our case also. Fontana–Masson stain specific to melanin is also helpful in visualization of fungal elements in tissue specimens. Enzyme linked immunosorbent assay for detection of F. pedrosoi and Cladophialophora carrionii have limited usefulness due to low sensitivity and specificity. Molecular techniques using ribosomal RNA polymerase chain reaction have been used in speciation and identification of new species and research purposes.[1] The treatment requires an individualized approach. The various treatment modalities used are medical, surgical excision/debridement, and physical destructive modalities. The firstline drugs are triazoles, allylamines, potassium iodide, amphotericin B, photodynamic therapy, and imiquimod.[123] Combination therapy using itraconazole (200–400 mg) and terbinafine (500–1000 mg) has been used synergistically for 3–6 months with good success. Newer antifungals such as posaconazole and voriconazole are also being used. Cryotherapy, thermal therapy, and surgical excision can be combined with medical modalities.[123] Patient should be kept under follow up to detect any recurrence or failure of treatment. Thus our case represents an uncommon morphological presentation of chromoblastomycosis and importance of an astute histopathology examination to clinch the diagnosis in culture-negative and resource-constrained scenarios.

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