The incisional biopsy of the lesion of the forearm showed epidermal ulceration with a dense dermal infiltrate of lymphocytes, plasma cells and epithelioid histiocytes, with necrotizing granuloma formation and extension into the subcutaneous fat (Figs. 2, 3, 4 and 5). Many multinucleated giant cells were present, some containing oval conidia and hyphal forms (Figs. 6 and 7). Adjacent vessels showed necrosis of the vessel walls. PAS with diastase and Gomori methenamine silver stains highlighted the conidia and branching septate hyphae, present within giant cells as well as extracellularly (Figs. 8 and 9). Careful examination revealed a few characteristic tadpole or sperm-shaped conidia at the end of conidiophores (Fig 10).
Culture on Sabouraud dextrose agar yielded a moderately rapid growth of brownish gray to dark gray (mouse gray), fluffy colonies which intensified in color with continued incubation. On light microscopy, single and small clusters of annelloconidia or "fruiting bodies" were seen on branched or simple conidiophores, the latter developing terminally or laterally from vegetative hyphae. The conidia were light brown and oval or club shaped (see sketch, Fig 11).