Paraganglia of the prostate. Location, frequency, and differentiation from prostatic adenocarcinoma.

In contrast to paraganglia of the urinary bladder, prostatic paraganglia have been largely unreported. Following the discovery of paraganglia in two separate radical prostatectomy specimens, we reviewed 100 randomly selected radical prostatectomy specimens to document the location and frequency of prostatic paraganglia. Twelve additional paraganglia were identified in eight resections, for a total of 14 paraganglia in 10 cases. Most paraganglia were located in or adjacent to lateral neurovascular bundles and, rarely, in lateral prostatic stroma. The size of paraganglia ranged from 0.1 to 1.7 mm (median 0.9 mm). Paraganglia consisted of clusters of cells in patterns that ranged from lobular to diffuse, usually with a prominent stromal vascular component. The cells contained bland oval nuclei and clear cytoplasm, which was often abundant. Occasionally, larger cells with larger nuclei were present. Immunohistochemical stains for chromogranin, neuron-specific enolase, and synaptophysin were positive; those for prostatic-specific antigen were uniformly negative. In one of our cases, histologic similarity was noted between a paraganglion and an adjacent prostatic adenocarcinoma with a "hypernephroid" pattern. Recognition of prostatic paraganglia, with appropriate immunohistochemical stains when necessary, will obviate the possibility of confusing these structures with prostatic adenocarcinoma.