The cytomorphologic diagnosis of mantle cell lymphoma (MCL) can be difficult and requires ancillary studies for accurate subclassification. More than 95% of MCLs are known to carry the t(11;14) chromosomal translocation. However, traditional cytogenetic studies on cytologic material can be both difficult technically and time consuming. Interphase fluorescence in situ hybridization (FISH) can be a powerful tool for detecting chromosomal changes in individual tumor cells. The authors evaluated the utility of interphase FISH for the rapid detection of t(11;14) in archival cytologic material.
The cytopathology data bases at two institutions were searched for patients with well characterized MCL (biopsy, immunophenotyping). Ten patients with MCL (8 fine-needle aspiration samples and 2 body cavity fluid samples) were identified. The area of interest on the cytology slides was marked and hybridized with two-color, locus-specific identifier DNA probes. A dual-fusion probe signal was used to detect the juxtaposition of the immunoglobulin heavy-chain (IgH) (14q32) locus with cyclin D1 (CCND1) gene sequences (11q13). Samples with tumor cell nuclei that showed at least one yellow fusion signal in addition one green signal (IgH) and one orange signal (CCND1) were interpreted as positive. Positive and negative controls were used.
The t(11;14) translocation was detected by FISH in 10 of 10 patients (100%) with MCL.
The cytomorphology of small-to-intermediate cell lymphomas, including MCL, follicular lymphoma, and marginal zone/mucosa-associated lymphoid tissue lymphoma, can show overlapping cytomorphologic features with one another as well as with reactive lymphoid proliferations. In selected samples in which specific classification is not possible or when confirmation is required on a small sample size, molecular analysis and cytogenetics may be helpful in arriving at an unambiguous cytodiagnosis and subclassification. Distinction of MCL from other lymphomas is important, because the clinical course is aggressive, and response to conventional chemotherapy is poor. This study showed that the detection of t(11;14) by FISH can be performed rapidly and easily on archival cytologic material for the molecular diagnosis of MCL.