Fahed Al-Soud¹, Valentina Grekos², Rishbha Dua^1,, Sharani Jayaratne², Fahreen Lalani², George Michel¹, Karthik Mohan³

Colonoscopy is the gold standard for adenoma and adenocarcinoma detection. Here we present a rare case of a patient who presented with large bowel cancer despite a negative colonoscopy, no signs or symptoms, and a negative CT scan. This patient ordered a CEA marker only because his sister was diagnosed with colon cancer; the CEA marker came back elevated. He also had a CT scan which came back negative, with the suggestion of doing a PET scan. The PET scan finally found the suspicious mass. The patient had a bowel resection with metastatic spread to the peritoneum but all surrounding lymph nodes were negative. However, an inguinal lymph node was inflamed and later biopsied which showed metastatic carcinoma suggesting an adnexal skin carcinoma or primary urothelial carcinoma. The patient denied any skin carcinoma and also followed up with a cystoscopy which came back with normal results.

colon cancer, colon adenocarcinoma, right hepatic adenocarcinoma, hepatic flexure CRC, case report