title: Composite cutaneous lymphoma in a patient with rheumatoid arthritis treated with methotrexate.
abstract: Patients with rheumatoid arthritis, whether treated or not with immunosuppressive agents including methotrexate, have an increased risk of lymphoproliferative disorders. Termed "iatrogenic immunodeficiency-associated lymphoproliferative disorders" in the 2008 World Health Organization classification of lymphoid neoplasms, they include Hodgkin and non-Hodgkin lymphomas. Composite lymphomas are rare, particularly in skin, with none reported in immunodeficiency states. We report the case of a 67 year-old woman with a long history of rheumatoid arthritis, on methotrexate treatment, who developed multiple skin lesions exhibiting a malignant infiltrate displaying both B- and T-cell phenotypes and dual clonal gene rearrangement by polymerase chain reaction, consistent with a cutaneous composite lymphoma. The patient received chemotherapy including rituximab with partial response, but the T-cell component recurred. To the best of our knowledge, this is the first case report of a cutaneous composite lymphoma in a patient with an iatrogenic immunodeficiency representing a dual challenge, diagnostic for the pathologist and therapeutic for the hematologist.
authors.affiliation: Department of Pathology, McGill University and McGill University Health Center, Quebec, Canada.
authors.forename: Hassan
authors.initials: H
authors.lastname: Huwait
authors.forename: Beatrice
authors.initials: B
authors.lastname: Wang
authors.forename: Chaim
authors.initials: C
authors.lastname: Shustik
authors.forename: René P
authors.initials: RP
authors.lastname: Michel
mesh_terms: D000368:Aged; D018501:Antirheumatic Agents / Q000009:adverse effects*; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000188:drug therapy / Q000473:pathology*; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D015322:Gene Rearrangement, B-Lymphocyte / Q000235:genetics; D015329:Gene Rearrangement, T-Lymphocyte / Q000235:genetics; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor / Q000235:genetics; D006801:Humans; D016393:Lymphoma, B-Cell / Q000139:chemically induced / Q000235:genetics / Q000473:pathology*; D016410:Lymphoma, T-Cell, Cutaneous / Q000139:chemically induced / Q000235:genetics / Q000473:pathology*; D008727:Methotrexate / Q000009:adverse effects*; D009378:Neoplasms, Multiple Primary / Q000139:chemically induced / Q000235:genetics / Q000473:pathology*; D012878:Skin Neoplasms / Q000139:chemically induced / Q000235:genetics / Q000473:pathology*
chemical_list: D018501:Antirheumatic Agents; D004273:DNA, Neoplasm; D008727:Methotrexate