Basidiobolomycosis: Case series

Abstract

Basidiobolus ranarum is a fungus found in the dung of amphibians, reptiles and insectivorous bats. Basidiobolomycosis is a chronic subcutaneous infection of the trunk and limbs caused by B. ranarum. The disease is a well-known infection in the tropical areas. It usually presents with subcutaneous or gastrointestinal lesions and rarely with systemic affection. Recently, the etiologic role of B. ranarum in the gastrointestinal infections has been increasingly recognized. Here, we retrospectively reviewed the records of five patients with basidiobolomycosis, all from the same geographic region (Tohama area, Aseer province, southern region of the Kingdom of Saudi Arabia). All the cases presented with prolonged fever and other manifestations suggestive of either chronic infection (such as tuberculosis) or malignancies (such as lymphoma). The diagnosis of gastrointestinal basidiobolomycosis was established on histolological ground (granulomatous reaction, dense infiltrate of eosinophils and fungal structures). One case was diagnosed based on the histological features combined with positive tissue culture for B. ranarum. One case was treated by surgical resection of fungal masses (Case I), followed by itraconazole and amphoterecin-B therapy. The other four cases had non-resectable fungal masses and they responded very well for antifungal therapy (cases II, III, and IV received amphotericin-B and itraconazole and case V received amphotericin-B and voriconazole). Our study raises several notions. Gastrointestinal basidiobolomycosis is often misdiagnosed as cancer (lymphoma or carcinoma), tuberculosis or inflammatory bowel disease. Its recognition needs high index of suspicion and increased awareness especially in patients with chest, abdominal or neck masses and eosinophilia. The diagnosis of basidiobolomycosis can be established on histological basis in most cases. The fungal morphology and the Splendore-Hoeppli phenomenon are characteristic histological features of this condition. There are no prominent risk factors. Usually, surgery and prolonged antifungal therapy are required.