title: Methotrexate-associated EBV-positive vasculitis in the skin: a report of two cases simulating rheumatoid vasculitis.
abstract: Rheumatoid vasculitis (RV) is one of the most serious extra-articular complications of rheumatoid arthritis (RA), generally treated with a high dose of immunosuppressive drugs. Recently, we encountered two cases of ulcerative vasculitis in methotrexate (MTX)-prescribed RA patients, which simulated RV; however, Epstein-Barr virus (EBV)-encoded RNA in situ hybridization on their skin biopsies revealed many EBV-positive lymphocytes (over 50 cells/high-power field) within the vessel walls and perivascular stroma, which led us to the diagnosis of EBV-related vasculitis instead of RV. Subsequently, both ulcers regressed after the discontinuation of MTX and no recurrence was noted during the follow-up period. To prevent unnecessary treatment, EBV-positive vasculitis should be added in the differential diagnosis of lymphocytic vasculitis observed in MTX-administered RA patients.
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Fujimoto
authors.affiliation: Department of Dermatology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Yo
authors.initials: Y
authors.lastname: Kaku
authors.affiliation: Department of Rheumatology and Clinical Immunology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Yamakawa
authors.affiliation: Department of Rheumatology and Clinical Immunology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kawabata
authors.affiliation: Department of Rheumatology and Clinical Immunology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ohmura
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Itsuko
authors.initials: I
authors.lastname: Koyanagi
authors.affiliation: Department of Rheumatology and Clinical Immunology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Tsuneyo
authors.initials: T
authors.lastname: Mimori
authors.affiliation: Department of Dermatology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kabashima
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Haga
keywords: Epstein-Barr virus (EBV); methotrexate (MTX); rheumatoid vasculitis; skin