Department of Pathology and Urology, College of Medicine, Hallym University, Seoul, Korea.
Inflammatory pseudotumor of the urinary bladder is a proliferative spindle cell lesion that microscopically may suggest a sarcoma but that are benign without a recent history of an operation. The first such case was reported by Roth, in 1980, and thereafter about seven more cases were reported in medical literatures. We reported a case of inflammatory pseudotumor of the urinary bladder mimicking leiomyosarcoma. Patient was a 36-year-old woman with complaint of painless total and gross hematuria for 3 weeks.
Partial cystectomy specimen showed a well-demarcated nodular mass of yellow white color, involving the submucosal and muscular layers. Microscopic examination revealed proliferating bundles of spindle cells interspersed with infiltration of many inflammatory cells including eosinophils. Spindle cells were positive for vimentin on immunohistochemistry and corresponding to myofibroblasts on the electron microscopic examination.