Mantle cell lymphoma (MCL) is a mature B-cell neoplasm composed of monomorphic small to medium-sized atypical lymphocytes arising from naïve mantle zone B-cells, with a generally aggressive and incurable clinical course. The t(11;14)(q13;q32) between [email protected] and CCND1 is present in almost all cases of MCL. Secondary cytogenetic abnormalities are common, and have been associated in some cases with clinical progression. Variant and cryptic t(11;14) translocations have been reported as well. Herein, we present the case of an 80-year old woman with classical MCL, and a cryptic t(11;14) translocation detected by fluorescence in situ hybridization (FISH), and not by conventional cytogenetics. FISH on previously G-banded metaphases showed a cryptic [email protected] fusion signal on a derivative chromosome 10, and another fusion signal on one of the abnormal copies of chromosome 11. Cases such as this highlight the importance of FISH studies as part of an algorithmic and multidisciplinary approach to diagnosis.