CD5-positive, cyclinD1-negative mantle cell lymphoma with a translocation involving the CCND2 gene and the IGL locus.

Distinguishing mantle cell lymphoma (MCL), from low-grade B-cell lymphoma is important because MCL is clinically more aggressive and is treated differently. Though most MCL overexpress cyclinD1 (CCND1) and have a t(11;14)(q13;q32), MCL that are negative for CCND1 exist. Some have translocations involving cyclinD2 (CCND2) and either the immunoglobulin heavy chain or kappa light chain locus. We present a CD5-positive, CCND1-negative B-cell lymphoma with a novel translocation involving CCND2 and the immunoglobulin lambda (IGL) gene. A 64-year-old male underwent resection of a polypoid mass of the ileum. Histology showed atypical, medium-sized lymphoid cells positive for CD20, CD5, CD43, and CCND2 by immunohistochemistry, and negative for CCND1, CCND3, and p27. Fluorescence in situ hybridization was negative for CCND1 abnormalities, but demonstrated a CCND2/IGL fusion. Clinical workup revealed stage IV disease. Current diagnostic criteria are insufficient for subclassifying this case, highlighting the need for additional studies on CCND2-translocated B-cell lymphomas to guide therapy appropriately.