Pathophysiology of IgG4-related hypophysitis: an analysis of 7 patients

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 163-194-Pituitary Disorders & Case Reports
Basic/Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-163
Hironori Bando*1, Genzo Iguchi1, Hidenori Fukuoka1, Masaaki Taniguchi2, Masaaki Yamamoto1, Kentaro Suda1, Hitoshi Nishizawa1, Michiko Takahashi1, Eiji Kohmura2 and Yutaka Takahashi1
1Kobe University Graduate School of Medicine, Kobe, Japan, 2Kobe University Graduate School of Medicine
IgG4-related disease is an emerging systemic autoimmune disease characterized by involving a wide range of organs including hypophysitis (e.g.(1)) . Although, Leporati et al. has recently proposed criteria for the diagnosis of IgG4-related hypophysitis based on the literature review of 11 cases (pituitary histopathology in 2 cases)  (e.g.(2)) , the detailed pathophysiology has not fully clarified because of a limited numbers of the cases. Here we demonstrate 7 cases of IgG4-related hypophysitis and performed a clinical pathological analysis.

To detect IgG4-related hypophysitis, we screened 44 patients, those with pituitary tumors had been excluded, who presented with hypopituitarism (PH)/ central diabetes insipidus (DI). IgG4-related hypophysitis was diagnosed according to the following criteria; (1) serum IgG4 concentration³a135mg/dl, and/or (2) co-existing other organ involvement observed in IgG4-related disease and/or (3) infiltration of a substantial number of IgG4-positive plasma cells in the obtained tissues.

Totally, 7 cases (3 males and 4 females) were diagnosed as IgG4-related hypophysitis. The mean age at the time of onset of hypophysitis was 61.8±8.8 years. The mean serum IgG4 concentration was 191.1±78.3 mg/dL. 4, 2, and 1 cases showed PH+DI, DI, PH, respectively. These pituitary dysfunctions did not improve after corticosteroid administration. 6 cases showed swelling of pituitary and/or pituitary stalk, and 1 case showed empty sella. 4 cases demonstrated an involvement of other organs including Mikulicz's disease, autoimmune pancreatitis, interstitial pneumonitis, orbital psuedotumor, and hypertrophic pachymeningitis. 2 cases developed hypophysitis during the tapering of glucocorticoid therapy for the other organ lesions.

We performed a histopathological analysis of the pituitary in 3 cases and of the other involved organs in 3 cases and confirmed the infiltrate of IgG4-positive plasma cells in these lesions. Intriguingly, we found a unique ‘storiform fibrosis’ in the HE staining of the pituitary tissue, which has been reported in IgG4-related pancreatitis (e.g.(3)) but not in hypophysitis previously in all 3 cases.

In conclusion, IgG4-related hypophysitis manifests various organ involvement and clinical course. The ‘storiform fibrosis’ in the pituitary pathology may be a useful marker for the diagnosis.

(1) Stone JH et al., NEJM 2012; 366: 539. (2) Leporati P et al., JCEM 2011; 96, 1971. (3) Deshpande V et al., Mod Pathol 2012 ; 25, 1181

Nothing to Disclose: HB, GI, HF, MT, MY, KS, HN, MT, EK, YT

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

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