Misdiagnosis as diffuse large B-cell lymphoma: clinicopathological analyses of 431 patients

Objective To analyze the cases that are easily misdiagnosed as diffuse large B-cell lymphoma (DLBCL), and to explore the diagnosis, differential diagnosis and clinicopathological features of DLBCL. Methods The clinicopathological data of 431 cases preliminarily diagnosed as DLBCL in the Department of Pathology, School of Basic Medical Science, Peking University from October 2016 to December 2017 were retrospectively analyzed. Further immunohistochemical staining and molecular biological tests were performed if necessary. Results The diagnostic accuracy rate of DLBCL was 88.86% (383/431). Misdiagnosis mainly occurred in follicular lymphoma (36 cases, 8.35%), high-grade B-cell lymphoma (HGBL) with gene rearrangement of c-myc and bcl-2 or bcl-6 (4 cases, 0.93%), atypical lymphoid tissue hyperplasia (3 cases, 0.70%), mantle cell lymphoma (3 cases, 0.70%), classic Hodgkin lymphoma (CHL) (1 case, 0.23%) and composite lymphoma (DLBCL and CHL) (1 case, 0.23%). Except the poor quality of sections, the lack of immunohistochemical markers, the poor knowledge of the diagnosis of DLBCL and high-grade FL as well as HGBL were the main reasons of misdiagnosis. Conclusions The diagnosis and differential diagnosis of DLBCL is based on morphology, and it needs to combine with the corresponding immunohistological markers and molecular biological detection when necessary. The recognition of clinical and pathological features of various types of misdiagnosed lymphomas should be strengthened. Key words: Lymphoma, large B-cell, diffuse; Lymphoma, follicular; High-grade B-cell lymphoma; Misdiagnosis; Differential diagnosis