Anal Neuroendocrine Tumor Masquerading as External Hemorrhoids: A Case Report.

Neuroendocrine tumors in gastrointestinal (GI) tract are a rare source of GI malignancy with an estimated incidence of 2.5 - 5 per 100,000 people per year and the prevalence of 35 per 100,000. In the GI tract, they are located in decreasing order of frequency in appendix, ileum, rectum, stomach, and colon. Those found in the anal region represent just 1% of all malignancies of the anal canal. Their clinical presentation can be widely varying, sometimes being found incidentally with metastatic disease and an unknown primary source. We report a case of a 60-year-old male who presented with a 2-week history of intermittent bright red blood per rectum and anal pain. He was found to have a lesion in the perianal area which was subsequently diagnosed has a poorly differentiated large cell type neuroendocrine carcinoma (NEC) with hepatic metastasis.