Is there a route for metachronous inguinal lymph node in colonic cancer? A case report

As the inguinal lymph nodes do not serve as the primary route for the lymphatic drainage of the colon, inguinal metastasis from colorectal carcinomas is considered an unusual finding, especially in the 2nd year follow-up. A 76-year-old male patient, operated on for non-metastatic right colic adenocarcinoma, consulted 2 years after for a right inguinal swelling. A biopsy was performed. Unexpectedly, it showed an adenocarcinoma metastasis in favor of a colonic origin. There was no relapse of the disease. The pathological examination of the resected inguinal lymph node confirmed malignant cells from a colonic origin. As the positron emission tomography scan showed no other tumoral localizations, a multidisciplinary discussion ensued, culminating in the choice of chemotherapy for optimal pathological response. This case highlights the fact that colic drainage may encounter inguinal lymph nodes and thus inguinal groin metastasis could exceptionally have been seen in colonic carcinomas.