ABSTRACT
The first case in Thailand ofpseudosarcomatous tumor of the urinary bladder is reported. A 32-year-old female, presented with gross hematuria and dysuria. Cystoscopy showed large mass floating in the bladder and biopsy of the tumor showed to be leiomysarcoma. IVP was normal but CT scanning showed huge mass occupied the whole bladder and invasion outside the anterior wall was suspected. The bladder was explored and the tumor with part of the bladder around the tumor’s stalk was resected. A microscopic section revealed spindle cell proliferation exhibiting mitotic activity within myxoid stroma. The election microscopic finding showed myofibroblast. The final diagnosis was pseudosarcomatous fibromyxoid tumor. The patient was followed up for 5 years and no evidence of recurrence has been detected.