[A CASE OF PRIMARY MUCOSA-ASSOCIATED LYMPHOID TISSUE (MALT) LYMPHOMA OF THE URINARY BLADDER].

A 68-year-old female presented with macroscopic hematuria. Cystoscopy revealed a wide-based submucosal mass. Computed tomography revealed a 3.5 × 2.5-cm solitary mass situated from the trigone to the left lateral bladder wall and the left hydroureter and hydronephrosis. T2-weighted magnetic resonance imaging (MRI) revealed low intensity, and diffusion-weighed MRI showed increased diffusion without invasion. The bladder tumor was immediately resected transurethrally. Histological diagnosis of the tissue obtained by transurethral resection was extranodal marginal zone B cell lymphoma of MALT. Positron emission tomography-CT showed no lesions other than the bladder tumor. The patient was diagnosed with stage-IE lymphoma of the bladder (Ann Arbor classification). Radiotherapy was performed at the bladder and pelvis (30 Gy) with six courses of rituximab (375 mg/m²). No local or distant recurrence after a 48-month follow-up was noted.