Primary papillary carcinoma of the prostate: report of a histopathologic, cytologic and electron microscopic study on one case.

An unusual type of prostatic carcinoma is described. Histopathologic examination showed a papillary and acinar appearance. Aspiration cytology showed papillary fragments and sheets of malignant cells. The ultrastructural features of this tumor were similar to those reported for prostatic carcinoma rather than endometrial carcinoma supporting a prostatic orgin for this tumor.