Infiltrating, Quasi-Cancerous Rectal Lesions: Unique Manifestation of Visceral Basidiobolus ranarum

The case records of four children presenting with rectal involvement by the fungus Basidiobolus ranarum, were retrospectively analyzed for clinical presentation, hematological and radiological investigations, the procurement of histopathological material for diagnosis and the findings thereof, the treatment of these patients and the follow-up.

The four children presented with non-specific symptoms of fever, loss of weight and appetite, constipation and bleeding per rectum. One presented with excoriation and ulceration of the perineum and perianal skin. Examination generally unremarkable, however, showed the rectum extensively involved by a lesion which narrowed the lumen. Hematological investigations showed leukocytosis with eosinophilia and raised levels of acute phase reactants like ESR, platelets, and C-reactive proteins. Ultrasonogram (USG) and CT scan confirmed the lesion to be involving all layers of the rectum and compromising the rectal lumen. The right colon was also involved in one patient. One underwent a colonoscopy and biopsy which proved inconclusive. All four underwent a Tru-cut biopsy which was diagnostic. Histopathologically the disease was based in Basidiobolus ranarum, a fungus which is emerging as a cause of visceral abdominal involvement.

Lesions involving the rectum, and appearing to be neoplastic may be caused by the fungus Basidiobolus ranarum. The symptomatology and presentation may be non-specific. High levels of eosinophils in the blood, a raised ESR, and C-reactive protein may be useful pointers to the diagnosis. USG and CT scans localize the lesions and also provide a guide for biopsies. The characteristic histopathological findings are diagnostic and based on these, treatment with Itroconazole / Voriconazole is beneficial.