Ductal (endometrioid) adenocarcinoma of the prostate: a clinicopathological study of 16 cases.

Sixteen cases of ductal (endometrioid) carcinoma of the prostate are presented. The tumour presents in elderly men (age range 65-87 years) with haematuria or obstructive symptoms. Serum prostate specific antigen may be normal or raised. On cytoscopy, there is often an exophytic lesion in the region of the verumontanum. Histologically, two variants are recognized: papillary and cribriform, of which there were eight cases each. Eight cases consisted of pure ductal carcinoma and seven were mixed, containing a variable proportion of micro-acinar carcinoma. The associated micro-acinar carcinoma had a Gleason score of at least 5. One case of carcinosarcoma with a ductal epithelial component was also included. All cases displayed positive immunohistochemical staining for prostate specific antigen and prostatic acid phosphatase and but were negative for the basal cell marker MA903. The tumour responds well to orthodox micro-acinar carcinoma therapy and appears notably sensitive to hormonal manipulation. Follow-up of the mixed group is restricted to a maximum of 3 years. Of the eight pure cases, five patients are still alive with survival periods of 11, 8, 7, 3 and 1 years. Three patients died of intercurrent disease of which one patient survived 12 years, having received no treatment. This tumour, therefore, can be regarded as having a good prognosis.