Signet ring cell carcinoma of a pulled-through sigmoid colon mimicking a primary invasive bladder tumor: case report and review of the literature.

Primary signet ring cell carcinoma of the urinary bladder and colon are rare disease entities that are aggressive, difficult to manage, and portend a poor prognosis. We present a case report of a 25-year-old man born with an imperforate anus who developed signet ring cell carcinoma of the pulled-through sigmoid colon that mimicked a primary invasive bladder tumor. Despite radical surgery and adjuvant radiation, the patient died of his disease 7 months after surgery.