Richter-like Pleomorphic Mantle Cell Lymphoma Composed of Epstein-Barr Virus–Positive Hodgkin-like Cells, a Diagnostic Challenge

Abstract

Mantle cell lymphoma (MCL) is an aggressive non-Hodgkin lymphoma with distinctive clinicopathologic features including the presence of t(11;14)(q13;q32) in almost all cases. Histologically identifiable variants are well described. Most MCLs are the classic variant, although more aggressive variants including blastoid and pleomorphic exist. The pleomorphic variant is a morphologic subtype composed predominantly of large atypical lymphoid cells. This variant can arise de novo or occur in patients with previous history of MCL as result of disease progression and clonal evolution. Mantle cell lymphoma is characteristically Epstein-Barr virus (EBV) negative. Here, we present an extremely unusual case of pleomorphic MCL that arose in a 69-year-old man with a previous 10-year history of indolent chronic leukemia. This case was unusual and diagnostically challenging because the large and pleomorphic lymphoma cells were EBV positive and had Hodgkin-like morphologic features and only focal cyclin D1 expression. Fluorescence in situ hybridization studies confirmed the presence of the CCND1-IgH gene rearrangement. The disease was clinically aggressive, and the patient died 12 months after diagnosis. Epstein-Barr virus–associated MCL and large cell progressions of MCL are only rarely reported. The additional features we describe, including only focal expression of cyclin D1 and Hodgkin-like morphology, make this an even more unusual and therefore difficult to identify lymphoma. Importantly, this case raises the question as to whether MCL can have histopathologic progressions analogous to the well-established EBV-associated Hodgkin-like Richter transformations of chronic lymphocytic leukemia/small lymphocytic lymphoma.