[Clinicopathological and molecular genetic features of cyclin D1-negative mantle cell lymphoma]

Objective: To investigate the clinicopathological features and molecular genetics of cyclin D1-negative mantle cell lymphoma (MCL). Methods: The clinicopathological features and molecular genetics of CyclinD1-negative MCL diagnosed between January 2016 and July 2021 at the First Affiliated Hospital of Zhengzhou University were analyzed using immunohistochemistry and fluorescence in situ hybridization. Clinical information was collected and analyzed. Results: A total of five Cyclin D1-negative MCL cases from all 212 MCL patients (5/212, 2.4%)were included. There were three male and two female patients,age ranged from 59 to 70 years (median 64 years). All patients presented with nodal lesions. None of the patients had B symptoms but four had bone marrow involvement. Histopathologically, four cases were classic MCL and one case was pleomorphic variant type. All five cases were negative for Cyclin D1 but SOX-11 were positive in all cases. CD5 was positive in four cases and one case was weakly positive for CD23. CD10 and bcl-6 were negative in all cases. CCND1 translocation was identified in three cases and CCND2 translocation in one case by FISH analysis. However,CCND3 translocations were not found in the five cases. Conclusions: Cyclin D1-negative MCL are uncommon, its accurate diagnosis needs combined analysis with morphologic and immunophenotypic characteristics and genetic changes. It may be particularly difficult to distinguish from other small cell type B cell lymphomas. FISH analyses for CCND1/CCND2/CCND3 translocations and immunohistochemistry for SOX-11 are helpful to resolve such a difficult distinction.