title: Multicentric Castleman Disease With Tubulointerstitial Nephritis Mimicking IgG4-related Disease: Two Case Reports.
abstract: Multicentric Castleman disease is a benign lymphoproliferative disorder with heterogenous clinical symptoms and involves systemic organs in addition to lymph nodes. Elevated serum IgG4 levels and IgG4-positive plasma cell (IgG4+PC) infiltrates have been reported in lymph nodes, lung and skin in some multicentric Castleman disease cases, resembling IgG4-related disease (IgG4-RD) histologically. However, no report has been available regarding IgG4+PC infiltration in the kidneys of multicentric Castleman disease. Here, we report 2 cases of multicentric Castleman disease complicated by IgG4-related disease (IgG4-RD) histologically. However, there has been no report published on PC-rich tubulointerstitial nephritis, lymphadenopathy, with numerous IgG4+PC infiltration, and elevated serum IgG4 levels, mimicking IgG4-RD. The blood examinations revealed systemic inflammation and elevated C-reactive protein and interleukin-6 levels. Corticosteroid therapy was partially effective in both cases, and combination therapy of corticosteroid and tocilizumab was needed in both cases. Moreover, after triple therapy with corticosteroid, rituximab and cyclophosphamide were used in 1 case to tame the severe inflammation. The present cases suggest that if continuously elevated serum C-reactive protein levels and partial corticosteroid responsiveness are encountered, multicentric Castleman disease should be considered rather than IgG4-RD as a differential diagnosis even if serum IgG4 is elevated and IgG4+PCs infiltrate systemic organs.
authors.affiliation: *Department of Internal Medicine, Division of Rheumatology †Department of Internal Medicine, Division of Cardiology ‡Department of Human Pathology, Kanazawa University Graduate School of Medicine, Kanazawa §Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Zoshima
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yamada
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hara
authors.forename: Ichiro
authors.initials: I
authors.lastname: Mizushima
authors.forename: Masakazu
authors.initials: M
authors.lastname: Yamagishi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Harada
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Sato
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kawano
mesh_terms: D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis*; D005871:Castleman Disease / Q000150:complications / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007074:Immunoglobulin G; D008232:Lymphoproliferative Disorders / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009395:Nephritis, Interstitial / Q000209:etiology*; D010950:Plasma Cells / Q000473:pathology
chemical_list: D007074:Immunoglobulin G