Ascending colon cancer with synchronous external iliac and inguinal lymph node metastases but without regional lymph node metastasis: a case report and brief literature review.

Lymph node metastasis to the iliac or inguinal region of colon cancer is extremely rare. We experienced a case of ascending colon cancer with synchronous isolated right external iliac and inguinal lymph node metastases but without any regional lymph node metastasis. An 83-year-old woman was admitted to our hospital due to anemia. Colonoscopy and computed tomography revealed an ascending colon cancer and also right external iliac and inguinal lymph node swelling. Further examination by F-deoxyglucose positron emission tomography strongly suggested that these lymph nodes were metastatic. Right hemicolectomy with lymph node dissection along the superior mesenteric artery, and right external iliac and inguinal lymph node dissection were performed. Histological examination revealed that both lymph nodes were metastasized from colon cancer, and there was no evidence of regional lymph node metastasis. The patient has shown no sign of recurrence at 27 months after surgery.