Mucinous cystic neoplasm in submucosa of the bladder

A 48-year-old man, with a history of advanced gastric cancer, underwent computed tomography (CT) for a postoperative 5 year follow-up. The CT scan showed a small bladder tumor. Pelvic magnetic resonance imaging and cystoscopy were performed consecutively, which revealed a small, ovoid and well-demarcated submucosal tumor at the anterior bladder, but without mucosal abnormality. The patient underwent a mass enucleation, which was 2×1.5×1cm in size, and light-pinkish, multi-lobulated and encapsulated. On the cut section, it was revealed to be a unilocular cyst, filled with brownish mucoid material. A histological examination showed focal stratified mucinous epithelium, without cellular atypia, which was admixed with mucinous pool formation. There was no evidence of a metastatic tumor or a tumor of urachal origin. Thus, it was diagnosed as a primary mucinous cystic neoplasm in the submucosa of the bladder, as initially thought, which has never been reported in the literature.