[Prostate cancer with an unusual course]

The case of a 60 years old patient with peritoneal carcinomatosis of a tumor with small cell histology is reviewed. At presentation, biopsy of a rectal palpatory finding revealed a small cell carcinoma, infiltrating the mucosa. A laparotomy was done, which showed a grotesque peritoneal carcinomatosis of the same histology with masses retro- and infraperitoneally and in the pelvis. Clinically and histologically a probable epithelial peritoneal mesothelioma was diagnosed. The patient survived half a year only. Autopsy and post-mortem work-up demonstrated the presence of a small cell prostatic cancer, positive for both prostate specific antigen and acid phosphatase. A discussion of diagnostic procedures and differential diagnoses is given.