Myopericytoma in urinary bladder: a case report.

<bold>Background: </bold>Myopericytoma is reported to occur mainly in the skin and superficial soft tissue of the extremities. In contrast, occurrence in the urinary bladder is extremely rare.<bold>Case Presentation: </bold>We describe a 75-year-old Japanese man who developed a submucosal tumor at the right trigone of his bladder that led to interference with the discharge of right ureteral calculus. No invasive growth was observed by magnetic resonance imaging. Transurethral resection was successfully performed; histopathological analysis revealed perivascular proliferation of spindle-shaped to oval-shaped, cytologically bland tumor cells with eosinophilic cytoplasm. On immunohistochemical examination, the tumor cells were positive for alpha-smooth muscle actin, desmin, CD34 and h-caldesmon.<bold>Conclusion: </bold>Cystoscopic and pathological findings were compatible with a diagnosis of myopericytoma of the urinary bladder. [ABSTRACT FROM AUTHOR]