Diagnostic Challenges in Pediatric Basidiobolomycosis: A Case of Retroperitoneal Mass and Multisystem Complications

Introduction: Gastrointestinal basidiobolomycosis (GIB) is a rare fungal infection caused by Basidiobolus ranarum, often misdiagnosed as inflammatory bowel disease (IBD) or malignancy. This misidentification frequently results in diagnostic delays and severe complications, including hydronephrosis and thrombosis. Case Presentation: An 11-year-old boy presented with abdominal pain and significant weight loss, accompanied by a retroperitoneal mass causing bilateral hydronephrosis and venous thrombosis. Histopathological evaluation confirmed basidiobolomycosis. Due to adhesions, surgery was not feasible, but antifungal therapy with voriconazole and amphotericin B led to clinical improvement, with plans for extended follow-up. Conclusions: The nonspecific symptoms of GIB and its similarity to other conditions highlight the critical role of histopathological examination in diagnosis. Faster diagnosis and antifungal therapy are crucial for preventing potential complications. This case underscores the necessity for a high index of suspicion for GIB in children presenting with unexplained abdominal symptoms and abdominal mass. Timely diagnosis and tailored management can significantly enhance outcomes.