• immunohistochemistry;
  • prostate;
  • stromal sarcoma

We report a case of a 65-year-old man with rare prostatic stromal sarcoma in which suprapubital radical prostatectomy was performed, but neither chemotherapy nor radiation therapy were administered before or after the operation. The well-circumscribed tumor, measuring 5 cm in diameter, showed a homogeneous white grayish cut surface with a hard consistency. Histopathologically, the tumor consisted mainly of medium-sized rounded cells with a sarcomatous and epithelioid appearance intermingled with collagen fiber. Hyalinized foci were also noted in the tumor. Immunohistochemistry revealed that the tumor cells were diffusely positive for vimentin and focally positive for progesterone receptor and CD34, but not for EMA, cytokeratin or estrogen receptor. No recurrence or distant metastasis of the tumor has occurred in 8 years of follow up. The tumor was diagnosed as prostatic stromal sarcoma (PSS) showing epithelioid differentiation and of a progesterone-dependent nature. Possible favorable nature of the PSS might be expected after complete resection.