Pseudosarcomatous fibromyxoid tumor of the prostate: A case report with immunohistochemical, electron microscopic, and DNA flow cytometric analysis

A 22-year-old man presented with symptoms of urinary obstruction and was found to have a 5-cm mass protruding from the left side of the prostate into the prostatic urethra. The lesion was partially removed by transurethral resection (TURP). The patient's symptoms recurred, so he required another TURP four months later; at latest follow-up (four years later), there was no evidence of disease. Light microscopy revealed a myxoid lesion characterized by an atypical fibroblastic proliferation associated with a prominent inflammatory component and granulation tissue-type vasculature. The lesion nearly replaced the prostatic parenchyma and invaded the bladder wall. Immunohistochemistry and electron microscopy showed a predominance of fibroblasts with occasional myofibroblasts. DNA flow cytometric analysis showed that the tumor cells had a diploid DNA content. Given these findings and the indolent clinical course, the authors think that this lesion represents a benign, reactive process consistent with a pseudosarcomatous fibromyxoid tumor, a recently described rare lesion of the genitourinary tract.