Cyclin D1-negative mantle cell lymphomas (MCL) are not well characterized, in part due to the difficulties in their recognition. SOX11 has been recently identified as a reliable biomarker of MCL, also expressed in the cyclin D1-negative variant. We investigated 40 lymphomas with MCL morphology and immunophenotype, negative for cyclin D1 expression/t(11;14)(q13;q32) but SOX11-positive. These tumors presented clinically with generalized lymphadenopathy, advanced stage, and had a poor outcome (5-year overall survival 48%). Chromosomal rearrangements of the CCND2 locus were detected in 55% of the cases, with an IG gene as partner in 18/22 cases, in particular with light chains (10 IGK@, 5 IGL@). No mutations in the phosphorylation motifs of CCND1, CCND2 and CCND3 were detected. The global genomic profile and the high complexity of the 32 cyclin D1-negative SOX11-positive MCL analyzed by copy number arrays were similar to the conventional cyclin D1/SOX11-positive MCL. 17p deletions and high Ki67 expression conferred a significantly worse outcome to the patients. This comprehensive characterization of a large series of cyclin D1-negative MCL indicates that these tumors are clinically and biologically similar to the conventional cyclin D1-positive MCL and provides a basis for the proper identification and clinical management of these patients.