Schwannoma of the seminal vesicle in a patient with rectal cancer

Introduction: Schwannomas are benign tumors arising from the cells responsible for producing the myelin sheath surrounding peripheral nerve cells. Presentation of case: A patient presented with intermittent bloody stools and diarrhea. Following a work-up, including colonoscopy, computed tomography (CT) scan, and endorectal ultrasound and biopsy, he was found to have a clinical T3N1 rectal adenocarcinoma. The CT scan also showed an incidental mass in the right seminal vesicle that on biopsy was consistent with a benign stromal nodule. After neoadjuvant chemoradiation, a low anterior resection (LAR) and concomitant resection of the right seminal vesicle was performed. Pathologic evaluation of the right seminal vesicle revealed a benign schwannoma. Discussion: This unusual case of a solitary schwannoma of the seminal vesicle in a patient with a locally advanced rectal adenocarcinoma illustrates the difficulty in diagnosing these rare lesions because of their generally asymptomatic nature.