• Satoshi Ikeda, Akimasa Sekine, Tomohisa Baba, Koji Okudela, Tae Iwasawa, Fumikazu Sakai, Kenji Notohara, Kenichi Ohashi, Tamiko Takemura, and Takashi Ogura.
• Department of Respiratory Medicine, Kanagawa Cardiovascular and Respiratory Center, Yokohama, Japan.
• Histopathology. 2017 Jan 1; 70 (2): 242-252.

AimsThere have been few reports on immunoglobulin-G4 (IgG4)-related interstitial pneumonia (IP), and its clinical features remain unclear. The objective of this study was to assess whether IP with marked IgG4-positive plasma cell infiltration without extrathoracic lesions of IgG4-related disease (RD) should be diagnosed as a subtype of IgG4-RD or a separate entity.Methods And ResultsAll consecutive patients with surgical lung biopsy-proven idiopathic IP with an IgG4/IgG-positive cell ratio of >40% and >50 IgG4+ plasma cells in a high-power field without extrathoracic lesions of IgG4-RD were reviewed retrospectively. Five patients were enrolled into this study. All patients were male with a history of smoking. Four patients met the comprehensive diagnostic criteria for IgG4-RD. The remaining patient lacked data related to the serum IgG4 level. Histologically, a non-specific IP pattern was observed in all patients. The key morphological features of IgG4-RD, such as storiform fibrosis and obliterative phlebitis with lymphoplasmacytic infiltration in a loose background texture, were absent in every patient. In contrast, venule obstruction by densely packed lymphoplasmacytic infiltration was observed in two patients. Marked scarring and remodelling of the lung were also noted, which is not seen typically in IgG4-RD. A favourable response to corticosteroid monotherapy was observed in all patients; however, two patients developed lung cancer during the course of observation.ConclusionsIP with marked IgG4-positive plasma cell infiltration without extrathoracic lesions of IgG4-RD had different pathological features from those of IgG4-RD, and it is appropriate to regard this as a separate entity.© 2016 John Wiley & Sons Ltd.

16 keywords...

hide…