Oclussive bowel obstruction caused by an Unusually Late Case of Metachronous Colorectal Cancer After 22 Years

Abstract

Introduction: Metachronous colorectal cancer (CRC) refers to a new primary colorectal malignancy developing at least six months after the initial diagnosis and treatment of a primary CRC. While most cases occur within the first 5 years postoperatively, delayed presentations beyond a decade are rare and poorly characterized.

Case Presentation: We report the case of a 62-year-old male with a history of transverse colon cancer resected in 2003 and treated with adjuvant chemotherapy. In 2025, after experiencing multiple episodes of bowel obstruction and initially refusing surgery at another clinic, he presented to our surgical department with diffuse abdominal pain, nausea, vomiting, altered bowel habits, and bloating. Imaging revealed a thickened segment of the descending colon with near-complete luminal narrowing and upstream distension. Surgery confirmed two synchronous tumors: (A) a low-grade adenocarcinoma of the descending colon infiltrating to the subserosa without nodal metastasis (pT3N0R0) and loss of MSH-6 expression; and (B) a mucinous adenocarcinoma of the rectum infiltrating the muscularis propria without nodal metastasis (pT2N0R0) and also with loss of MSH-6 expression. The patient underwent total colectomy with ileorectal anastomosis and segmental jejunal resection. Postoperative recovery was favorable.

Conclusions: This case highlights the possibility of extremely delayed metachronous CRC, occurring over two decades after initial treatment. It underscores the importance of individualized long-term surveillance strategies and the role of colonoscopy in detecting asymptomatic lesions. Recognition of atypical recurrence patterns is essential for timely diagnosis and intervention.

Keywords: Metachronous colorectal cancer; colonoscopy surveillance; delayed recurrence; total colectomy; colorectal neoplasia.