Gastrointestinal Basidiobolomycosis Mimicking Crohn's Disease in a Young Adult

Gastrointestinal basidiobolomycosis (GIB) is a rare, emerging fungal infection caused by <i>Basidiobolus ranarum</i>. It primarily affects immunocompetent individuals and often presents as a mass lesion mimicking colorectal malignancy or inflammatory bowel disease. Due to its non-specific presentation and rarity, GIB is frequently misdiagnosed, leading to delayed or inappropriate management. In this article, we present a case of GIB in a young male in his 20s who presented with a four-month history of intermittent and recurrent severe abdominal pain associated with significant weight loss. Based on the information at hand, he was being treated for a suspected inflammatory bowel disease. Subsequently, he underwent a gastroscopy and colonoscopy. His colonoscopy initially reported him to have acute severe destructive colitis with a wide differential diagnosis, including inflammatory bowel disease, Bechet's disease, ischemic or pseudomembranous colitis. Based on initial suspicion, the patient was started on therapy for Crohn's disease, with which he showed mild improvement. However, he again got worse with exacerbating symptoms. His histopathology was sent to a tertiary care hospital in the United States, and he was found to have GIB. After initiation of antifungal therapy, including a combination of itraconazole and intravenous liposomal amphotericin (later changed to voriconazole), his symptoms showed remarkable improvement. This case report highlights the importance of recognizing the rare presentation of GIB in an immunocompetent adult who was initially misdiagnosed as a case of inflammatory bowel disease, emphasizing the importance of histopathological evaluation in diagnosing fungal infections. It also indicated that GIB, despite being a highly destructive colitis, can be successfully treated with antifungals without the need for invasive surgical procedures.