title: CD20-positive primary gastric T-cell lymphoma poorly responding to initial treatment with rituximab plus CHOP, and a literature review.
abstract: There have been rare reported cases of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) that co-expressed CD20. A 44-year-old Japanese male was initially misdiagnosed as CD20-positive diffuse large B-cell lymphoma with a background of reactive CD3-positive T-cells in the stomach. After four cycles of R-CHOP [rituximab plus cyclophosphamide (CY), doxorubicin, vincristine, and prednisolone (PSL)], total gastrectomy with regional lymph node dissection was performed due to the poor response to R-CHOP. A final diagnosis of CD20-positive primary gastric PTCL-NOS was made based on the immunohistochemical, flow cytometric, and molecular genetic findings. In the present case, CD20 immunostaining for T-cell lymphoma cells in tumor tissue varied; in a large part, these were strong to weak-positive, and in some parts, absent. We additionally reviewed the literature focusing on CD20-positive PTCL-NOS treated with rituximab. The administration of rituximab has been performed as an initial treatment in 11 cases, including the case reported here. The response was good in cases with high expression of CD20, while it was poor in cases with variable intensity in CD20 staining, which is consistent with our experience in the present case. The efficacy of rituximab may be associated with intensity of CD20 expression in T cells and its homogeneity in the tumor tissue.
authors.affiliation: Department of Hematology, Asahikawa City Hospital, 1-65, Kinseicho-1, Asahikawa, 070-8610, Japan. y_kakinoki@city.asahikawa.hokkaido.jp.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Kakinoki
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Hashiguchi
authors.affiliation: Department of Hematology, Asahikawa City Hospital, 1-65, Kinseicho-1, Asahikawa, 070-8610, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishio
authors.affiliation: Department of Hematology, Asahikawa City Hospital, 1-65, Kinseicho-1, Asahikawa, 070-8610, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Chiba
authors.affiliation: Department of Pathology, School of Medicine, Kurume University, Kurume, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Niino
authors.affiliation: Department of Pathology, School of Medicine, Kurume University, Kurume, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Ohshima
mesh_terms: D000328:Adult; D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage; D018951:Antigens, CD20 / Q000032:analysis*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use*; D003520:Cyclophosphamide / Q000008:administration & dosage; D004317:Doxorubicin / Q000008:administration & dosage; D005743:Gastrectomy; D006801:Humans; D008197:Lymph Node Excision; D016399:Lymphoma, T-Cell / Q000175:diagnosis / Q000276:immunology / Q000628:therapy*; D008297:Male; D011241:Prednisone / Q000008:administration & dosage; D000069283:Rituximab / Q000627:therapeutic use*; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000276:immunology / Q000628:therapy*; D013601:T-Lymphocytes / Q000276:immunology; D017211:Treatment Failure; D016896:Treatment Outcome; D014750:Vincristine / Q000008:administration & dosage
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D018951:Antigens, CD20; C571759:R-CHOP protocol; D000069283:Rituximab; D014750:Vincristine; D004317:Doxorubicin; D003520:Cyclophosphamide; D011241:Prednisone
keywords: CD20; Peripheral T-cell lymphoma; Primary gastric lymphoma; Rituximab