Abstract
A 78-year-old woman was admitted to our hospital with tarry stools. Endoscopic examination of the small intestine by oral single-balloon enteroscopy revealed irregular ulcerated lesions with bleeding at the proximal ileum. The patient underwent exploratory laparotomy with resection of a segment of the small intestine as well as the regional mesenteric lymph nodes. Histopathological examination of the surgical specimen revealed transmural infiltrates of centrocyte-like lymphoma cells with a marginal zone distribution. The lymphoma cells had a CD5-, CD10-, CD19+, CD20+, CD21+, CD22+weak, and CD23- immunophenotype, and expressed α/λ-type immunoglobulins. The karyotype was 46,XX,t(11;18)(q21;q21)/47,idem,+der(11)t(11;18)(q21;q21), and fluorescence in situ hybridization on the interphase nuclei confirmed the BIRC3-MALT1 fusion. The presence of IgA-λ-type monoclonal proteins in the serum and BIRC3-MALT1-positive cells with plasma cell morphology in the bone marrow indicated that the lymphoma was a disseminated disease. The patient was treated with 6 doses of rituximab; however, her serum IgA levels remained high. The centrocyte-like cytomorphology of lymphoma cells with marginal zone distribution and the presence of t(11;18)(q21;q21)/BIRC3-MALT1 fulfilled the diagnostic criteria of extranodal marginal zone lymphoma of the MALT type. The incidence of this type of lymphoma developing in the small intestine may increase with the introduction of balloon-assisted enteroscopy.
