Cellular pseudosarcomatous fibroepithelial stromal polyp of the renal pelvis.

Cellular pseudosarcomatous fibroepithelial stromal polyp is an underrecognized lesion described in the lower female genital tract. We here report the clinical, histological, and immunohistochemical features of a cellular pseudosarcomatous fibroepithelial stromal polyp located in the renal pelvis. A 47-year-old woman was referred with a 4-month history of left flank pain and gross hematuria.