Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma of the Urinary Bladder: A Case Report of a Rare Presentation.

Primary lymphoma of the urinary bladder is extremely rare. We present the case of a 67-year-old woman diagnosed with primary extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) of the urinary bladder. The patient presented with macroscopic hematuria. Renal ultrasound revealed a solid vascularized mass, in the inferior wall of the bladder. Pelvic computed tomography (CT) and magnetic resonance imaging (MRI) confirmed the presence of a polypoid lesion on the left side of the inferior bladder wall, measuring 40x45 mm, and the MRI study with gadolinium revealed that the entire bladder wall was involved. The patient underwent transurethral resection of the bladder tumor, demonstrating a histologic extensive involvement of bladder tissue by MALT lymphoma. The patient was treated with radiotherapy (24 Gy in 12 fractions) and four cycles of rituximab. She remained without evidence of disease 12 months later.