Crystalloids of prostatic carcinoma: relationship to Bence-Jones crystals.

Previously undemonstrated protein crystalloid structures were found to occur in the malignant acini of prostatic carcinomas in 23% of cases systematically reviewed. Histochemically and immunohistochemically, they appear closely related, if not identical, to Bence-Jones crystals. Thus, the prostatic carcinoma cell is the first neoplastic cell besides those of the lymphocytic-plasmacytic series shown to produce such crystalline structures. Like the proteolytic splitting of amyloid from Bence-Jones proteins, it is postulated that prostatic epithelium may enzymatically split corpora amylacea from a Bence-Jones-like protein which it synthesizes. It is further postulated that malignant prostatic cells may lack the necessary enzymatic machinery to accomplish this with resultant accumulation of crystalloids within their acini. Prostatic crystalloids were never found in benign glands with rare exceptions and then were limited to benign appearing glands adjacent to carcinoma. The presence of such crystalloids in microscopic sections of prostate may be of diagnostic aid in determining the presence of malignancy or of a premalignant state.