The punch biopsy specimen demonstrated prominent necrotizing granulomatous inflammation in the dermis. Special stains, including Gomori methenamine-silver and periodic acid–Schiff stains, showed structures that were consistent with Prototheca organisms. Both single endospores and sporangia that were also consistent in size and configuration with Prototheca organisms were identified. Fite stains were negative for acid-fast bacilli, and a Gram stain was negative for bacteria. The mycobacterial culture was negative for organisms, and the bacterial tissue culture only yielded a moderate growth of E cloacae. The fungal culture was also negative, presumably because of the paucity of Prototheca organisms as visualized on Gomori methenamine-silver staining or because of overgrowth of bacteria.
Nonhealing Leg Ulceration. Arch Dermatol. 2000;136(10):1263-1268. doi: