Benign Prostatic Hyperplasia Mimicking a Symptomatic Rectal Submucosal Tumor

We report the case of a 56-year-old man with a prostatic mass that extended into the rectal mucosa. He experienced constipation and anal bleeding for 6 months. He underwent surgical ablation for an approximately 5-cm, benign, subepithelial cystic mass in the rectum, which was adjacent to a 5-cm solid mass located on the prostatic gland seen on computed tomography and magnetic resonance imaging (MRI) of the pelvis. One year after the surgery, the patient had recurrent anal bleeding with difficulty defecating. The pelvic MRI scan showed a solid mass with heterogeneous enhancement that was compressing the rectum. The sigmoidoscopic exam showed a 4-cm mass protruding through the anterior rectal mucosa 7-cm above the anal verge. Ultra-low anterior resection with ileostomy and prostatectomy was performed for curative resection of the mass with extension into the rectum. However, the pathologic report showed massive benign prostatic hyperplasia involving the rectum, but not penetrating into the rectal mucosa. The patient did not complain of any symptoms including constipation and anal bleeding, until 18 months after the surgical resection. This is the first reported case of benign prostatic hyperplasia mimicking a rectal submucosal tumor in a patient presenting with anal bleeding and constipation.