Isolated Rectal Polypoid Lesion as the Initial Presentation of Crohn's Disease

Crohn's disease can present with atypical and isolated manifestations, contributing to diagnostic delays. We describe a 45-year-old woman undergoing routine colorectal cancer screening who was found to have a 30–40 mm rectal polypoid lesion and a persistent perianal abscess later identified as a fistula. Endoscopic appearance suggested segmental disease, and histopathology revealed granulomatous chronic colitis. Infectious etiologies were excluded. This case highlights an unusual presentation of Crohn's disease and emphasizes the importance of considering inflammatory bowel disease in persistent perianal disease to prevent misdiagnosis and treatment delays.