Citation: International Journal of Surgical Pathology. 27(1):98-101, 2019 Feb..Journal: International journal of surgical pathology.Published: ; 2019ISSN: 1066-8969.Full author list: Starr A; Kwon DH; Kallakury B.UI/PMID: 29968492.Subject(s): Adult | Antigens, CD20/an [Analysis] | *Biomarkers, Tumor/an [Analysis] | Epstein-Barr Virus Infections/co [Complications] | Herpesvirus 4, Human | Humans | Leukocyte Common Antigens/an [Analysis] | *Lymphoma, Large B-Cell, Diffuse/di [Diagnosis] | Lymphoma, Large B-Cell, Diffuse/vi [Virology] | MaleInstitution(s): MedStar Washington Hospital CenterDepartment(s): PathologyActivity type: Journal Article.Medline article type(s): Journal ArticleDigital Object Identifier: https://dx.doi.org/10.1177/1066896918784669 (Click here)ORCID: Starr, Amy https://orcid.org/0000-0001-9894-4058Kwon, Dong Hyang https://orcid.org/0000-0002-4927-9175 (Click here) | (Click here)Abbreviated citation: Int J Surg Pathol. 27(1):98-101, 2019 Feb.Abstract: Diffuse large B-cell lymphoma (DLBCL) is characterized by medium- to large-sized neoplastic cells that express a wide range of B-cell markers including CD19, CD20, CD22, and CD79a. Also, as this is a hematopoietic malignancy, there is expression of the leukocyte common antigen CD45. Lack of CD20 expression occurs in a specific rare heterogeneous subgroup of DLBCL including primary effusion lymphoma, plasmablastic lymphoma, ALK-positive large B-cell lymphoma, and large B-cell lymphoma arising in HHV8+ multicentric Castleman disease. In this article, we report a rare case of CD20- and CD45-negative Epstein-Barr virus-positive DLBCL in which the entities listed above were ruled out, thereby posing a significant diagnostic challenge. Arriving at the correct diagnosis of Epstein-Barr virus-positive DLBCL was supported by immunoreactivity for the B-cell transcription factor Oct-2 and the pan-B cell marker CD79a.