title: Pituicytoma: characterization of a unique neoplasm by histology, immunohistochemistry, ultrastructure, and array-based comparative genomic hybridization.
abstract: The pituicytoma is a rare neoplasm whose histogenesis is debated partly because of the diversity of tissue types present in the sellar region. In this article we illustrate the characteristic histologic, immunohistologic, and ultrastructural features of this unique neoplasm. Furthermore, we use array-based comparative genomic hybridization to demonstrate a unique pattern of genomic copy number aberrations in pituicytomas. Tumors were composed of bipolar, spindle cells that were immunopositive for S100, vimentin, and Bcl-2 and immunonegative for synaptophysin, chromogranin, and glial fibrillary acidic protein. Ultrastructural analysis was remarkable for absence of secretory granules. Array comparative genomic hybridization demonstrated genomic copy number imbalances, including losses on chromosome arms 1p, 14q, and 22q and gains on 5p. This pattern of genetic changes only partially overlaps with the genomic alterations reported in pituitary adenomas. In summary, our data suggest that pituicytomas are a unique subset of tumors of the sellar region.
authors.affiliation: Neuropathology Unit, University of California-San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143-0102, USA. joanna.phillips@ucsf.edu
authors.forename: Joanna J
authors.initials: JJ
authors.lastname: Phillips
authors.forename: Anjan
authors.initials: A
authors.lastname: Misra
authors.forename: Burt G
authors.initials: BG
authors.lastname: Feuerstein
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kunwar
authors.forename: Tarik
authors.initials: T
authors.lastname: Tihan
mesh_terms: D002874:Chromosome Mapping; D055028:Comparative Genomic Hybridization; D005260:Female; D018628:Gene Dosage; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D035583:Rare Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D022142:Secretory Vesicles / Q000648:ultrastructure