Primary bladder mucosa-associated lymphoid tissue lymphoma: A case report and literature review.

Introduction: Primary bladder mucosa-associated lymphoid tissue (MALT) lymphoma is a rare tumor. To date, the PubMed database contains only 39 English articles covering 63 cases of primary bladder MALT lymphoma. Herein, we report a case of this disease and review the current literature.
Patient Concerns: A 77-year-old woman presented with frequent urination, urinary urgency, and dysuria for 3 years. In the past 3 years, the patient's symptoms recurred and progressively worsened, and she was admitted to the hospital.
Diagnosis: A histopathological examination revealed the bladder mass as a tumor with high proliferation of atypical B-lymphocytes. Immunohistochemistry showed positive results for CD20, PAX-5, Ki-67, BCL-2, and CD21 and negative results for CD10, MUM1, TDT, and cyclin D1. These data supported the diagnosis of primary bladder MALT lymphoma.
Interventions: A transurethral resection of bladder tumor was performed to treat the disease.
Outcomes: The patient was alive and healthy at the 15-month follow-up.
Conclusion: Primary bladder MALT lymphoma is a rare disease and can be easily missed or misdiagnosed before achieving a histological confirmation. Surgery may be the best choice for both diagnosis and treatment.