Metastatic prostatic carcinoma to supradiaphragmatic lymph nodes. A clinicopathologic and immunohistochemical study.

We identified 26 cases of metastatic prostatic carcinoma in supradiaphragmatic lymph nodes from 1972-1987. All involved nodes (15 supraclavicular, eight cervical, two axillary, and one mediastinal) were taken from the left side. Of those cases with available data, serum acid phosphatase was normal in five of 21 (24%). Seven of 20 (35%) had no evidence of bone metastases. Rectal examination was normal in eight of 19 cases (42%). While seven cases had a history of prostate cancer, the rest presented with enlarged nodes alone or with simultaneous urinary obstructive symptoms. Eighteen patients died following node biopsy (mean 19.8 months, range 1-46 months). Twenty-two of 26 metastases were high grade and often were not histologically suggestive of prostate carcinoma. In general, immunohistochemical staining for prostate-specific acid phosphatase (PSAP) was more intense than for prostate-specific antigen (PSA), in contrast to several other reports using these antisera. Metastatic prostate carcinoma should be ruled out by using immunoperoxidase for PSA and PSAP in all men over 45 presenting with carcinoma of unknown primary origin in left-sided supradiaphragmatic lymph nodes, even in the absence of bony disease, elevated serum acid phosphatase (SAP), abnormal rectal examination, and a histologic picture suggesting prostate carcinoma.