title: Fibrous meningioma with tyrosine-rich crystals.
abstract: A 58-year-old African-American woman presented with a 6-month history of headaches. A magnetic resonance imaging scan of the head revealed a 5-cm, enhancing dura-based mass in the left parietal region. The variably cellular tumor was composed of uniform spindle cells associated with intercellular collagen and numerous radially arranged "petal-shaped" clusters of eosinophilic crystals. The tumor was diagnosed by light microscopy as a fibrous meningioma. Ultrastructural examination disclosed cells with complex interdigitating processes connected by desmosome-like cell junctions, abundant intercellular collagen fibers, and prominent, densely osmiophilic crystals featuring radiating teardrop shaped petals emanating from a central core. A positive Millon reaction showed these crystals to consist at least in part of tyrosine. By morphology, histochemistry, and ultrastructure, the crystals resembled tyrosine-rich crystals occurring in salivary gland tumors. This is the first report of a fibrous meningioma containing tyrosine-rich crystals.
authors.affiliation: Department of Pathology, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Couce
authors.forename: A
authors.initials: A
authors.lastname: Perry
authors.forename: P
authors.initials: P
authors.lastname: Webb
authors.forename: J J
authors.initials: JJ
authors.lastname: Kepes
authors.forename: B W
authors.initials: BW
authors.lastname: Scheithauer
mesh_terms: D003460:Crystallization; D003896:Desmosomes / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008279:Magnetic Resonance Imaging; D008577:Meningeal Neoplasms / Q000737:chemistry* / Q000601:surgery / Q000648:ultrastructure; D008579:Meningioma / Q000737:chemistry* / Q000601:surgery / Q000648:ultrastructure; D008875:Middle Aged; D013194:Staining and Labeling; D014443:Tyrosine / Q000032:analysis*
chemical_list: D014443:Tyrosine