Breaking the Mold: A Rare Case of Invasive Colonic Aspergillosis Causing Toxic Megacolon and Perforation in a Patient Without Classic Immunosuppression

Invasive gastrointestinal aspergillosis is rare and typically occurs in immunocompromised hosts. We present a case of a 24-year-old man with intermittent corticosteroid use presenting with diarrhea and abdominal pain found to have toxic megacolon on imaging. He developed colonic necrosis and perforation requiring emergent colectomy. Histopathology revealed invasive Aspergillus with transmural necrosis. His course was complicated by septic shock, acute kidney injury requiring dialysis, and pulmonary candidiasis. Primary colonic aspergillosis in immunocompetent patients is exceedingly uncommon. This case highlights the importance of early consideration of invasive fungal infection and prompt antifungal treatment in a patient with fulminant colitis unresponsive to standard therapy.