Adenoid cystic carcinoma of the prostate: a case report with immunohistochemical and in situ hybridization staining for prostate-specific antigen.

A 43-year-old man with urinary outlet obstruction was referred to our hospital. A digital rectal examination revealed an elastic hard prostate. The serum prostate-specific antigen (PSA), serum prostatic acid phosphate and gamma-seminoprotein levels were found to be within the normal range, and transrectal ultrasound sonography provided normal findings. The patient underwent a subcapsular prostatectomy under a diagnosis of benign prostatic hyperplasia. Histopathologically, the lesion was diagnosed as an adenoid cystic carcinoma of the prostate. Because a further examination revealed a pathologic extension into the urinary bladder, a radical cystoprostatectomy was performed. The expression of PSA protein and PSA mRNA was studied by means of immunohistochemistry and an in situ hybridization technique. The adenoid cystic carcinoma in the patient did not show any positive signs for PSA protein or PSA mRNA.