Gastrointestinal basidiobolomycosis: an unusual fungal infection mimicking colon cancer.

CONTEXT: -Basidiobolomycosis is a rare disease caused by the fungus Basidiobolus ranarum, an environmental saprophyte found worldwide. Patients with B ranarum infection may present with subcutaneous, gastrointestinal, or systemic lesions. Gastrointestinal basidiobolomycosis poses diagnostic difficulties, as its clinical presentation is nonspecific, with no identifiable risk factors. OBJECTIVE: -To discuss and compare the clinical features and histopathologic findings and other ancillary techniques that could be helpful in identifying gastrointestinal basidiobolomycosis. DESIGN: -We report 3 cases of gastrointestinal basidiobolomycosis and describe the clinical and morphologic findings while emphasizing the importance of identifying this unusual entity on endoscopic biopsies, thus avoiding unnecessary major surgeries. Fungal cultures were also performed, which are of diagnostic significance. Our first patient was lost to follow-up; however, patients 2 and 3 were followed up for 4 and 2 years, respectively. RESULTS: -In all 3 cases, patients presented with a clinical profile suggestive of malignancy. None of the patients gave any specific history. There was widespread abdominal disease with peritoneal involvement and colonic masses. Colonoscopic biopsy specimens showed nonspecific inflammation in 1 case; however, they showed only granulomatous inflammation in a second case and granulomas associated with fungal hyphae in a third. Typical morphology included hyphae, irregularly branched, thin-walled, occasionally septated and surrounded by a thick eosinophilic cuff (Splendore-Hoeppli phenomenon). CONCLUSION: -Gastrointestinal basidiobolomycosis can be detected on small endoscopic biopsy. The unequivocal diagnosis requires microbiologic cultivation of the fungus obtained from tissues. The prognosis for this disease is usually favorable as seen in 3 of our cases; however, cases with fatal outcome are on record.