Metachronous common iliac lymph node metastasis after rectosigmoid colon cancer resection: A case report

Introduction and importance: Metastases to common iliac lymph nodes from cancer of the rectosigmoid are extremely rare. We report a patient with a right common iliac lymph node metastasis after rectosigmoid cancer resection. Case presentation: The patient is a 57-year-old woman diagnosed with rectosigmoid cancer (Stage IIIc) who underwent laparoscopic resection followed by 8 courses of adjuvant chemotherapy with capecitabine. Sixteen months after resection, an intra-abdominal mass and a left lung nodule were found on computed tomography scans, which were suspected to be recurrences. Exploratory laparoscopy showed that the abdominal lesion was an enlarged common iliac lymph node, which was completely excised. No other intraabdominal recurrences were found. Subsequently, a left upper lobe lung metastasis was resected thoracoscopically. However, multiple lung metastases developed four months after the lung resection, and systemic therapy was begun. Clinical discussion: A lower incidence of lateral lymph node metastases from cancer in the rectosigmoid has been reported. Direct lymphatic pathways from the sigmoid colon or rectosigmoid to lateral lymph nodes have been suspected, which may be associated with the poor prognosis in this patient. Conclusion: A metachronous metastasis to a common iliac lymph node from primary rectosigmoid cancer is reported. Common iliac lymph node metastases from rectosigmoid cancer might have more malignant potential, and should be treated in the same manner as peri-aortic lymph node metastases.