title: Plasmacytic differentiation in MALT lymphomas following treatment with rituximab.
abstract: Mucosa-associated lymphoid tissue (MALT) lymphomas are B cell neoplasms which commonly affect the gastrointestinal (GI) tract. Gastrointestinal MALT lymphomas rarely show plasmacytic differentiation (PCD), and limited data on the potential influence of the anti-CD20 antibody rituximab (R) on PCD exist in the current literature. We have retrospectively analyzed patients with GI MALT lymphomas treated with R-containing regimens because restaging is routinely performed by repeated biopsies with pathohistological response assessment. Twenty-one patients with GI MALT lymphoma were identified to have undergone R-containing therapy. In 19 patients, the lymphoma originated in the stomach, while the colon was the primarily affected organ in two cases. Four patients received R monotherapy and 17 combinations of R with various chemotherapeutic agents. Only two patients with gastric MALT lymphoma had PCD before initiation of therapy. In 7 of 19 patients (37%) without PCD at diagnosis, restaging revealed PCD after or while on treatment with R-containing regimens. Out of these seven patients, only one patient had a complete response as opposed to 10/12 without PCD. These data suggest that R or R-containing treatment regimens may not optimally eradicate the plasma cell component and thus lead to PCD in patients with GI MALT lymphoma. In view of this, rebiopsy and histological re-assessment appear mandatory in patients failing/relapsing after R-containing regimens.
authors.affiliation: Division of Oncology, Department of Internal Medicine I, Comprehensive Cancer Center of the Medical University Vienna-General Hospital, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Marlene
authors.initials: M
authors.lastname: Troch
authors.affiliation: Division of Oncology, Department of Internal Medicine I, Comprehensive Cancer Center of the Medical University Vienna-General Hospital, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Barbara
authors.initials: B
authors.lastname: Kiesewetter
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine III, Comprehensive Cancer Center of the Medical University Vienna-General Hospital, Vienna, Austria.
authors.forename: Werner
authors.initials: W
authors.lastname: Dolak
authors.affiliation: Division of Haematology and Hemostaseology, Department of Internal Medicine I, Comprehensive Cancer Center of the Medical University Vienna-General Hospital, Vienna, Austria.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Jaeger
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine III, Comprehensive Cancer Center of the Medical University Vienna-General Hospital, Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Püspök
authors.affiliation: Division of Pathology, Department of Internal Medicine III, Comprehensive Cancer Center of the Medical University Vienna-General Hospital, Vienna, Austria.
authors.forename: Leonhard
authors.initials: L
authors.lastname: Müllauer
authors.affiliation: Division of Pathology, Department of Internal Medicine III, Comprehensive Cancer Center of the Medical University Vienna-General Hospital, Vienna, Austria.|Department of Pathology, Wilheminenspital, Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Chott
authors.affiliation: Division of Oncology, Department of Internal Medicine I, Comprehensive Cancer Center of the Medical University Vienna-General Hospital, Waehringer Guertel 18-20, 1090, Vienna, Austria. markus.raderer@meduniwien.ac.at.
authors.forename: Markus
authors.initials: M
authors.lastname: Raderer
mesh_terms: D000368:Aged; D058846:Antibodies, Monoclonal, Murine-Derived / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016130:Immunophenotyping; D018442:Lymphoma, B-Cell, Marginal Zone / Q000175:diagnosis* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010950:Plasma Cells / Q000378:metabolism / Q000473:pathology*; D012189:Retrospective Studies; D000069283:Rituximab
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents; D000069283:Rituximab