INTRALUMINAL CRYSTALLOIDS IN BREAST-CARCINOMA - IMMUNOHISTOCHEMICAL, ULTRASTRUCTURAL, AND ENERGY-DISPERSIVE X-RAY ELEMENT ANALYSIS IN 4 CASES

Objective.-lntraluminal crystalloids have been described in the prosta te, salivary gland, and ovary, but have not yet been reported in the b reast. We report four cases of breast carcinoma in which these crystal loids were found in ducts with intraductal carcinoma or atypical hyper plasia. The presence of intraluminal crystalloids may be a useful adju nct in making a diagnosis of carcinoma or may be a feature to look for as a marker for the presence of carcinoma. Design.-Four cases of brea st carcinoma containing intraluminal crystalloids were identified amon g 6900 surgical breast specimens between January 1990 and June 1995 at M. D. Anderson Cancer Center, Houston, Tex. Those sections with cryst alloids identified by hematoxylin-eosin stain were stained with period ic acid-Schiff, Alcian blue, and mucicarmine stains. Immunohistochemic al and ultrastructural studies and energy-dispersive x-ray analysis we re also performed on these sections. Results.-The intraluminal crystal loids were eosinophilic, varied in shape and size, and did not exhibit birefringence under polarized light. Immunohistochemically, the cryst alloids were negative for keratin, muscle-specific actin, and kappa an d lambda light chains, but the surfaces stained positively for epithel ial membrane antigen. By electron microscopy, the crystalloids had no limiting membrane and were composed of an electron-dense material with no discernible periodicity. By energy-dispersive x-ray element analys is, the crystalloids had no mineral content; however, sulfur was found , indicating a protein content.Conclusions.-The pathogenesis and const ituents of these intraluminal crystalloids remain to be determined. In asmuch as intraluminal crystalloids have not been found in normal duct s or acini, or in ductal hyperplasia without atypia, their presence ma y serve as a marker for breast carcinoma.