Secondary involvement of the urinary bladder in non-Hodgkin's lymphoma is relatively common; however, primary malignant lymphoma of this organ is extremely rare. The most common type of primary bladder lymphoma is a low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphoma. We report here on the imaging findings of a primary bladder lymphoma with bone marrow infiltration.
Three children aged 3-11 years had ultrasonography of the urinary tract for the investigation of dysuria and haematuria. A bladder mass was seen in these 3 children. One child had computed tomography scan, cystoscopy and bladder biopsy because rhabdomyosarcoma was considered. The biopsy revealed an inflammatory process. The urine culture of the other 2 children revealed E. coli. On ultrasonography, the inflammatory mass may appear homogeneously hypoechoic or may contain moderate level echoes. The mucosal surface of the mass may be smooth or lobulated. It is important to consider an infective cause for a bladder mass in children because computed tomography, cystoscopy and biopsy may be avoided.