Gastrointestinal basidiobolomycosis - Morphologic findings in a cluster ofsix cases

We describe the histopathologic features of 6 cases of gastrointestinal bas idiobolomycosis examined at 4 Phoenix, AZ area hospitals during the last 4 years. Resected stomach and intestinal specimens were characterized by mark ed mural thickening with fibrosis, prominent tissue eosinophil infiltration and palisading granulomatous inflammation around pale fungal hyphae. In 2 cases, there was colonic perforation. Basidiobolus ranarum hyphae (associat ed with spore-like spherules in 4 cases) were identified within tissue sect ions; the irregularly branched, thin-waited, occasionally septated hyphae w ere typically surrounded by a thick eosinophilic cuff (Splendore-Hoeppli ph enomenon). Although the histologic features of B ranarum are well described in the skirt and subcutaneous tissue, gastrointestinal involvement has pre sented considerable diagnostic difficulty. Before the occurrence of this cl uster of cases, intra-abdominal B ranarum infection has been reported only rarely.