title: Immunohistochemical study for IgG4-positive plasmacytes in pituitary inflammatory lesions.
abstract: On histology, IgG4-related hypophysitis is essentially similar to lymphocytic hypophysitis besides massive IgG4-positive plasmacyte infiltration. This immunohistochemical study was performed to investigate the presence of IgG4-positive plasmacytes in 14 various inflammatory lesions. Five cases of lymphocytic hypophysitis and a case of granulomatous hypophysitis were either negative or showed only a few IgG4-postive cells. A case of hypophysitis associated with pachymeningitis and a case of pituitary invasion of lymphoma were IgG4 negative. On the other hand, some IgG4-positive cells that tended to accumulate were observed in every six cases of secondary inflammation. In conclusion, immunohistochemistry for IgG4 can be a clue for differentiating IgG4-related hypophysitis from lymphocytic hypophysitis. However, clusters of IgG4-positive plasmacytes could be observed in secondary inflammation. Diagnosing hypophysitis with small biopsy specimen still remains troublesome.
authors.affiliation: Department of Neurosurgery, Tokyo Medical University, Tokyo, Japan. nishioka@tokyo-med.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishioka
authors.forename: Makoto
authors.initials: M
authors.lastname: Shibuya
authors.forename: Jo
authors.initials: J
authors.lastname: Haraoka
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007074:Immunoglobulin G; D007150:Immunohistochemistry; D007249:Inflammation / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010900:Pituitary Diseases / Q000276:immunology* / Q000473:pathology*; D010950:Plasma Cells / Q000276:immunology / Q000473:pathology*
chemical_list: D007074:Immunoglobulin G