title: Successful radiotherapy in a patient with primary rectal mucosa-associated lymphoid tissue lymphoma without the API2-MALT1 fusion gene: a case report and review of the literature.
abstract: Primary rectal MALT lymphoma is rare comprising less than 1% of MALT lymphomas. A 26-year-old man was referred to our hospital because of constipation and abdominal fullness. Colonoscopy revealed multiple submucosal tumors in rectum. Histopathological examination showed dense proliferation of small lymphoid cells, but lymphoepithelial lesions were not observed. The cells were CD5(-), CD10(-), CD20(+) and cyclinD1(-). The patient was diagnosed as having MALT lymphoma. The patient was negative for API2-MALT1 gene, and radiotherapy was performed and CR was achieved. With the accumulation of cases, establishment of a treatment strategy for primary rectal MALT lymphoma is expected in the future.
authors.affiliation: Department of Hematology, Comprehensive Cancer Center, International Medical Center, Saitama Medical University, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hagiwara
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Tamaru
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Kayano
authors.forename: Iturou
authors.initials: I
authors.lastname: Jin-nai
authors.forename: Masami
authors.initials: M
authors.lastname: Bessho
authors.forename: Nozomi
authors.initials: N
authors.lastname: Niitsu
mesh_terms: D000328:Adult; D006801:Humans; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics / Q000532:radiotherapy*; D008297:Male; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D012004:Rectal Neoplasms / Q000235:genetics / Q000532:radiotherapy*
chemical_list: C415943:API2-MALT1 fusion protein, human; D015514:Oncogene Proteins, Fusion