A Practical Approach to Diagnosis of B-Cell Lymphomas With Diffuse Large Cell Morphology.

CONTEXT.—: Large B-cell lymphomas represent the most common non-Hodgkin lymphomas and often present as extranodal masses with advanced stage similar to metastatic tumors. Without proper intraoperative, microscopic, immunophenotypic, and cytogenetic evaluation they may be mistaken for other hematopoietic or even nonhematopoietic tumors. Also, diffuse large B-cell lymphomas often have clinical, morphologic, immunophenotypic, and cytogenetic clinical features that are similar to those of other less common B-cell lymphomas. Furthermore, classification of these neoplasms is continually becoming more refined. OBJECTIVE.—: To provide a rational, methodic approach to the evaluation of large B-cell lymphomas for community practice pathologists who provide general pathology services. DATA SOURCES.—: This review incorporates guidelines detailed in the 2017 update to the World Health Organization's Classification of Tumours of Haematopoietic and Lymphoid Tissues in addition to other recent peer-reviewed publications. CONCLUSIONS.—: Many large B-cell neoplasms respond favorably to current treatments, but these cases also require accurate and timely diagnoses. We propose a process following a brief checklist that focuses on diffuse large B-cell lymphoma, the most common entity, and rules out other similar lymphomas in a stepwise fashion.