Primary malignant lymphoma of the urinary bladder: A case report

Primary malignant lymphoma of the bladder is rare and only 19 cases have been reported in Japan. We present an additional case and discuss the diagnosis and clinical problems. A 73-year-old woman was admitted with gross hematuria. Cystoscopy revealed smooth fungating pigmented masses on the posterior and lateral bladder wall. Microscopic examination showed a diffuse infiltrate of middle-sized cells with ellipsoid-shaped nuclei. Immunohistochemical markers showed a strong positive reaction with LCA, CD19, CD22, LN-3 Pan B and MB-1, which indicated a lymphoma of B-cell origin. The tumor was classified as a malignant lymphoma, diffuse B-cell type (kappa-monotype) intermediate type, medium type. Considering the peripheral blood picture, a diagnosis of primary malignant lymphoma of the bladder could be made. This patient received a course of telecobalt radiotherapy to the whole pelvis with a total dose of 40 Gy. Ultrasound scanning revealed that the thick layer of the low echoic lesion had become thin. Moreover, computerized tomography revealed that the thickness of the bladder wall had clearly recovered. Subsequent transurethral biopsy confirmed complete remission of the tumor cells and displacement of the bladder mucosa with granulomatous tissue. The patient remains well 24 months after her initial presentation.