title: Langerhans cell histiocytosis of the skull on cytologic squash preparations.
abstract: We present a case in which a primary cytodiagnosis of Langerhans cell histiocytosis (LCH) of the skull was made using squash preparations. The patient, a 25-year-old male, presented with raised intracranial pressure and decreased visual acuity. Magnetic resonance imaging revealed a large skull lesion with osteolytic features in the left frontal bone. The patient underwent surgical resection by the extended basal frontal epidural approach. The squash preparation smears were cellular and demonstrated a mixed population of small, mature lymphocytes, eosinophils, and a high histiocytes content. The histiocytes occurred as isolated or loosely cohesive and clustered. They possessed abundant cytoplasm with rounded cell shape and had characteristic nuclear features, composed of fine chromatin and delicate nuclear membranes. The cytologic features of these histiocytes were consistent with Langerhans cells (LCs). A final impression of LCH of the skull was rendered. Subsequent histopathology confirmed the diagnosis. LCs reacted with both S-100 protein and CD1a immunohistochemically. The demonstration of Birbeck granules on electron microscopic study was also noted. Whenever squash preparation yields a mixed population of mature lymphocytes, eosinophils, and histiocytes, the cytologists should be aware of and consider LCH as a diagnostic possibility.
authors.affiliation: Department of Pathology, Saiseikai Shiga Hospital, Imperial Gift Foundation Inc, Ritto, Shiga, Japan. tkkobaya@msn.com
authors.forename: Tadao K
authors.initials: TK
authors.lastname: Kobayashi
authors.forename: Masami
authors.initials: M
authors.lastname: Ueda
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nishino
authors.forename: Masamichi
authors.initials: M
authors.lastname: Bamba
authors.forename: Tadashi
authors.initials: T
authors.lastname: Echigo
authors.forename: Hideki
authors.initials: H
authors.lastname: Oka
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hino
authors.forename: Ikuko
authors.initials: I
authors.lastname: Fuse
authors.forename: Masato
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Katsumori
authors.forename: Chiyuki
authors.initials: C
authors.lastname: Kaneko
mesh_terms: D000328:Adult; D005624:Frontal Bone / Q000000981:diagnostic imaging; D006644:Histiocytes / Q000473:pathology / Q000648:ultrastructure; D006646:Histiocytosis, Langerhans-Cell / Q000175:diagnosis* / Q000473:pathology*; D006801:Humans; D008297:Male; D012886:Skull / Q000473:pathology*; D014057:Tomography, X-Ray Computed