Mycetoma-like chromoblastomycosis: a diagnostic dilemma

Mycetoma and chromoblastomycosis are subcutaneous fungal infections caused by pigmented fungi, common in the tropics and subtropics. Here we report a pregnant woman who presented with a swelling around the ankle joint which was clinically diagnosed as a case of mycetoma; however, further investigations revealed it to be a case of chromoblastomycosis.

24 year old primigravida presented with an indurated swelling around the ankle joint with multiple nodules and sinuses draining serosanguinous discharge. There was no improvement with antibiotic therapy or surgical debridement. Patient was investigated in detail including radiographs, KOH smear, pus culture and biopsy for histopathology and fungal culture.

o grains were identified from the discharge and KOH smear was negative for fungal elements. Pus culture revealed no bacterial growth. On the other hand, histopathology and fungal culture confirmed it to be a case of chromoblastomycosis caused by Fonsecaea pedrosoi. Treatment was initiated with terbinafine 250 mg daily, and patient showed excellent response within 6 months of therapy.

This unusual mycetoma-like presentation of chromoblastomycosis has not been previously reported in literature and may be attributed to the altered immune status in pregnancy. This should alert the clinician about the need to be vigilant of the atypical presentations of well-known dermatological conditions, especially in special situations like pregnancy.