A Case of Sigmoid Colon Cancer with a Solitary Metastasis to the Left Obturator Lymph Nodes

Abstract

A 65-year-old man being treated for type 2 diabetes mellitus in the Department of Endocrinology of our hospital was found to be anemic and underwent further gastrointestinal investigations. Lower gastrointestinal endoscopy showed a type 2 tumor in the sigmoid colon, which was diagnosed by biopsy as moderately differentiated adenocarcinoma. On PET-CT, there was FDG uptake in the left obturator lymph nodes in addition to the primary lesion. Open sigmoid colectomy (D3 dissection) and left lateral lymph node dissection were performed. The pathological diagnosis was muc, pSE, ly1, v0, pN0, pM1a (LYM), pStage IV. Postoperative adjuvant chemotherapy with capecitabine plus oxaliplatin was administered for 6 months. The patient remains recurrence-free 4 years postoperatively. The lateral lymph nodes are regarded as associated with the lower rectum, urinary bladder, prostate, and uterine adnexa, and lateral lymph node metastasis of a colorectal cancer other than rectal cancer is extremely rare. An extremely rare case of a solitary metastasis of sigmoid colon cancer to the left obturator lymph nodes is reported with a brief discussion of the literature.