Publication

Background: Ulcerative colitis (UC) typically develops in the rectum and progresses proximally. Segmental UC is a rare condition that is often difficult to diagnose. We present a case of segmental UC mimicking colon cancer that developed in the transverse colon. Case presentation: An 83-year-old woman with abdominal pain visited our hospital. Total colonoscopy revealed a granular mass with stenosis in the transverse colon. Biopsy specimen showed infiltration of inflammatory cells. No mucosal inflammation was evident on the anal side of the colon and rectum. Abdominal computed tomography showed enhanced mural thicknening in the transverse colon. Enlarged regional lymph nodes were apparent. Although no malignancy was evident, cancerlike stenosis and swollen lymph nodes were identified, so colectomy with regional lymph node resection was performed. The resected specimen showed near-circumferential thicknening. Aggregated small polypoid lesions and a mucosal bridge were also revealed. Histological findings showed a wide range of crypt abscess. No cellular atypia was found. We finally diagnosed segmental UC. The patient was subsequently followed closely without treatment, and abdominal distension developed one and a half years later. Total colonoscopy showed mucosal redness and erosion in the residual transverse colon. Pharmacotherapy immediately improved symptoms. As of 10 years postoperatively, she has experienced no further recurrence. Conclusion: We encountered a rare case of segmental UC in the transverse colon. UC does not always develop from the rectum and progress towards the oral side. Early definitive diagnosis can achieve good results for treatment and the clinical course.