Cutaneous cryptococcosis erroneously diagnosed as Histoplasma capsulatum infection.

A 31-year-old patient with stage 4 HIV/AIds presented with recurrent painful skin ulcers for more than 8 months. These would start as subcutaneous skin nodules, later becoming fluctuant and suppurating and then healing spontaneously (Fig. 1). The patient had lesions on the left wrist, left posterior thigh, right axilla, right posterior calf and right upper eyelid. He had also been diagnosed with extrapulmonary tuberculosis and had been on highly active antiretroviral therapy (HAART) for 8 months and antituberculosis medication (continuation phase). After initial poor adherence to both groups of drugs, compliance had improved. The Cd4 count at baseline was 16 cells/µl and the latest result was 80 cells/µl. Histological analysis of a biopsy specimen taken from the right upper eyelid lesion showed granulation tissue with some acute inflammation. Fungal spores were seen in the exudates and stains revealed 'capsule-deficient' fungi that were first thought to be Histoplasma, and were reported as such. Two pus swabs were sent for bacterial, fungal and mycobacterial culture. Gram stains revealed moderate numbers of (or ++) pus cells and the presence of fungal elements. Cryptococcus neoformans, which was sensitive to fluconazole, was isolated from both pus swabs and the biopsy specimen. A mixture of Gram-negatives and Gram-positives were thought to be colonisers. Ziehl-Neelsen stain and mycobacterial culture were negative. A diagnosis of disseminated cryptococcosis was made and treatment with fluconazole was commenced. Clinicians pointed out the discrepancy between the two reports. Another section was therefore stained with mucicarmine 1, 2 and the diagnosis was revised to C. neoformans infection (Fig. 2). The possibility of coinfection was ruled out by means of extended fungal culture, and the lesions responded clinically to fluconazole. Discussion Cryptococcal infection, usually presenting as meningoencephalitis, is being diagnosed more frequently in sub-saharan Africa because of the HIV/AIds pandemic. 3 However, presentations may vary and include skin lesions, lung infections and infections of other organs. CLINICAL IMAGES Fig. 1. Lesions at presentation: (left) granulomatous raised ulcers on the elbow; (right) spontaneously healing ulcer on the left side of the neck. Fig. 2. Mucicarmine-stained histology section showing a group of Cryp-tococcus cells with a dark-staining capsule against a brighter background (black arrow). Note the variation in size of the yeast cells and the difference in capsular thickness (seen with cutaneous cryptococcosis). G A Chipungu obtained his MB BS from University of Malawi's College of Medicine where he is employed as an assistant lecturer. He …