title: Crystalloids in salivary gland pleomorphic adenomas.
abstract: Two types of crystalloids in salivary gland pleomorphic adenomas were studied by light microscopy and electron microscopy. The first type of crystalloid, the previously described tyrosine-rich crystalloid, was identified in three (1.5%) of 205 cases. The crystalloids by light microscopy assumed a radial configuration, resulting in the characteristic petal-shaped morphology. Transmission electron microscopy revealed them to be electron-dense, lobular projections without internal structure. Scanning electron microscopy demonstrated a range of morphology from rounded and intact doughnutlike structures to aggregates of irregular, loosely cohesive plates. The crystalloids were backscatter positive by backscattered electron imaging, and by x-ray microanalysis exhibited prominent calcium, phosphorus, and magnesium peaks that were not present in the adjacent tumor tissue; these three elements may be important in the formation and structure of tyrosine-rich crystalloids. The second type of crystalloid was intraductal and birefringent and was identified in 26 (12.7%) of 205 cases. In 21 of these 26 cases the crystalloids were lost on 10% formaldehyde fixation and paraffin embedding. Histochemical stains and x-ray microanalysis did not reveal a definite chemical composition, but did suggest a predominantly organic nature.
authors.affiliation: Department of Pathology, Duke University, Durham, NC 27710.
authors.forename: P A
authors.initials: PA
authors.lastname: Humphrey
authors.forename: P
authors.initials: P
authors.lastname: Ingram
authors.forename: A
authors.initials: A
authors.lastname: Tucker
authors.forename: J D
authors.initials: JD
authors.lastname: Shelburne
mesh_terms: D008949:Adenoma, Pleomorphic / Q000032:analysis / Q000648:ultrastructure*; D003460:Crystallization; D004577:Electron Probe Microanalysis; D006801:Humans; D008855:Microscopy, Electron, Scanning; D012468:Salivary Gland Neoplasms / Q000032:analysis / Q000648:ultrastructure*; D014443:Tyrosine / Q000032:analysis
chemical_list: D014443:Tyrosine