[A Case of Primary Schwannoma of the Urinary Bladder]

A 68-year-old woman presented with a bladder tumor. She was asymptomatic, and the tumor was incidentally detected with radiological imaging performed during treatment of cervical cancer. Magnetic resonance imaging and computed tomography revealed a solitary submucosal tumor located in the anterior wall of the urinary bladder, with homogeneous contrast enhancement. Cystoscopy showed a submucosal tumor covered by normal mucosa. A paraganglioma was considered in the differential diagnosis, but symptoms suggesting hypercatecholaminemia were not apparent. Moreover, she did not have a family history or symptoms associated with neurofibromatosis-1 (NF-1). She underwent partial cystectomy with a preliminary diagnosis of submucosal bladder tumor. Histopathological diagnosis confirmed a schwannoma arising from the bladder wall. She was followed up without intravesical recurrence or metastases for 6 months. In the literature, only 12 cases of bladder schwannoma have been reported. There was no reported family history or symptoms associated with NF-1 in any of the cases. Although the number of cases is limited, literature review showed a favorable prognosis for bladder schwannoma with local tumor resection in patients without NF-1.