SkIndia Quiz 7: Giant erythematous plaque on the arm of an elderly woman.

A 55-year-old lady presented with an asymptomatic, gradually expanding patch over her left arm of over 5 years duration. She had occasional itching over the patch but offered no systemic complaints. Several years ago while handling firewood, a thorn had pricked her at the same site. Topical betamethasone and salicylic acid ointment applications would flatten the plaque temporarily with rebound upon stoppage. Various antifungal medications were also prescribed without relief.

On examination, the patient had a giant plaque over the posterior aspect of left arm measuring 10 × 5 cm with central clearing, crusting, and erythema on the periphery and an indurated margin [Figure 1]. The plaque was non-tender and sensations were intact. There was no similar or significant cutaneous finding elsewhere on her body. There was no regional lymphadenopathy. Except for an elevated ESR of 70 mm/h, baseline blood investigations and chest radiograph were normal. Mantoux test and KOH mount for fungus were negative. Histopathology revealed hyperkeratosis, irregular acanthosis, intra- and sub epidermal microabscesses, and small granulomas in the upper dermis composed of macrophages, epithelioid cells, and multinucleated giant cells [Figures 2 and 3].

Figure 1

Giant erythematous plaque with central clearing over the posterior aspect of the left arm with crusting and erythema on the periphery and indurated border

Figure 2

Intraepidermal and subepidermal microabscesses with macrophages, epithelioid cells, and multinucleate giant cells (H and E, ×40)

Figure 3

“Copper pennies” or Medlar bodies - fungal spores appearing as dark brown, thick walled, spherical bodies lying in a cluster of three at the centre (H and E, ×100)

ANSWER

Chromoblastomycosis

DISCUSSION

Chromoblastomycosis (chromomycosis) is often caused by one of five closely related species Phialophora verrucosa, Fonsecaea pedrosoi, Fonsecaea compacta, Exophiala jeanselmei, Exophiala spinifera, Rhinocladiella aquaspersa, and Clodosporium carrion.[1] It is a subcutaneous mycosis that might seriously evolve into secondary infection, lymphedema, elephantiasis, and occasionally squamous cell carcinoma. Lymphatic and hematogenous dissemination and brain metastases have rarely been observed.[2]

The disease is often contracted via direct inoculation usually after a thorn prick or trauma from wood splinters, etc.[3] It is very important to diagnose the disease at an early stage in view of its chronic evolutional course, recrudescent nature, potential association with squamous cell carcinoma, work incapacity, and poor quality of life.[4] A characteristic histopathological finding is the presence of fungal spores within giant cells and abscesses that appear as dark brown, thick walled, ovoid, or spherical bodies lying singly or in clusters, called “copper pennies” or Medlar bodies.[5]

Various treatments have been reported including surgical excision, cryotherapy, local heat application, itraconazole (200-400 mg/day for 6 to 12 months) and terbinafine (500mg/ day for 6 to 12 months). In refractory cases, these modalities may be combined. Other drugs with varied response are flucytosine, thiabendazole, and amphotericin B.[3] High cost of therapy, unavailability, toxicity, drug resistance, and relapse of infection are some of the limitations of treatment.[3]

This patient responded to itraconazole 400 mg/day for 8 months which was well tolerated. Liver enzymes and other blood parameters were monitored during the course of therapy. A high index of suspicion needs to be entertained whenever a chronic and expanding scaly annular plaque with central clearing presents to the clinician, especially with a history of local trauma and poor response to topical keratolytic therapy with or without steroids.