Intraluminal crystalloids in prostatic adenocarcinoma. Immunohistochemical, electron microscopic, and x-ray microanalytic studies.

Histochemical, immunohistochemical, electron microscopic, and x-ray microanalytic studies were performed on crystalloids within glandular lumina of adenocarcinomas of the prostate. In a review of light microscopic sections of 343 prostatic adenocarcinomas, unequivocal crystalloids were identified in 35 cases (10.2%). Immunohistochemical and ultrastructural studies revealed distinct differences between these crystalloids and the Bence Jones crystals of multiple myeloma: anti-kappa and anti-lamda immunostaining was negative, and the characteristic lattice-like architecture of Bence Jones crystals was not seen. Differences from corpora amylacea also were demonstrated. X-ray microanalysis did not elucidate the nature of the prostatic crystalloids, and their biochemical composition and mode of formation remain uncertain. Detection of the crystalloids in light microscopic sections nevertheless can aid in the diagnosis of prostatic adenocarcinoma, particularly when the tissue is distorted by crushing artifact, or if the tumor is so well-differentiated that it can be confused with atypical hyperplasia or inflammatory atypia. When intraluminal crystalloids are detected in prostatic glands that appear histologically benign or atypical, study of additional levels or a repeat biopsy should be undertaken.