title: A case report with plasmablastic lymphoma of the jejunum.
abstract: Plasmablastic lymphoma (PBL) is a recently identified entity that is considered to be a type of diffuse large B-cell lymphoma with a unique immunophenotype and a predilection for the oral cavity of patients with the human immunodeficiency virus (HIV). Although its clinical features may help in the differential diagnosis, an extraoral location in a patient without HIV makes it more difficult to suspect clinically. This case report is the first to describe a patient with PBL originating from the jejunum in a 60-yr-old, HIV-seronegative man. Computed tomography of the face, chest and abdomen showed about a 9.4 x 9.0 cm mass of the proximal jejunum, multiple masses in the musculoskeletal soft tissue, and multiple lymphadenopathies. The histological examinations demonstrated a large cell lymphoma with plasmablastic differentiation. The neoplastic cells were diffusely positive for MUM1, epithelial membrane antigen and lambda light chains, and focally positive for CD79a; but negative for CD3, CD20, CD30, CD34, CD45RO, CD56, CD99, and CD117. The proliferation index by Ki-67 immunohistochemistry was approximately 70%. These findings were compatible with the diagnosis of PBL. The findings in this case suggest that PBL should be included in the differential diagnosis of a small bowel mass even in a HIV-negative patient.
authors.affiliation: Department of Internal Medicine, University of Kyunghee College of Medicine, Seoul, Korea. dramc@hanmail.net
authors.forename: Jae Myung
authors.initials: JM
authors.lastname: Cha
authors.forename: Joung Il
authors.initials: JI
authors.lastname: Lee
authors.forename: Kwang Ro
authors.initials: KR
authors.lastname: Joo
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Jung
authors.forename: Hyun Phil
authors.initials: HP
authors.lastname: Shin
authors.forename: Jae Jin
authors.initials: JJ
authors.lastname: Lee
authors.forename: Gyo Young
authors.initials: GY
authors.lastname: Kim
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D016130:Immunophenotyping; D007580:Jejunal Neoplasms / Q000276:immunology / Q000473:pathology* / Q000628:therapy; D007583:Jejunum / Q000276:immunology / Q000473:pathology*; D016400:Lymphoma, Large-Cell, Immunoblastic / Q000276:immunology / Q000473:pathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged