Unusual radiologic features of metastatic prostatic carcinoma confirmed by immunohistochemical study.

The clinical application of an immunohistochemical technique for prostatic acid phosphatase allowed the accurate diagnosis of metastatic prostatic carcinoma in 17 patients whose condition was not recognized by either clinical or histologic observations. The cardinal manifestations in these 17 patients included supraclavicular lymphadenopathy in 7, hilar lymphadenopathy in 1, pulmonary infiltration in 2, simulating carcinoma of the rectum in 4, fracture of femur in 1, orbital tumor in 1, and brain tumor in 1. A retrospective analysis of the radiologic features of these patients showed that the unusual manifestations were due to the route of metastasis, that is, direct invasion, lymphatic, and hematogenous. Radiologic studies, even in these unusual cases, are both useful in establishing the diagnosis and helpful in delineating the mode of metastasis of prostatic carcinoma.