Cytogenetic Findings in Blastoid Mantle Cell Lymphoma

A subset of mantle cell lymphoma (MCL) tumors has blastoid morphology, and a number of morphologic variants of blastoid MCL have been described in the literature. In this report, we document the cytogenetic findings in 27 cases of blastoid MCL. Conventional cytogenetic analyses were performed on bone marrow aspirates involved by MCL from 27 patients. There were 14 men and 13 women with a median age of 63 years (range, 40-79 years). Diagnostic tissue biopsy and bone marrow specimens were reviewed, and cases were divided into 2 morphologic groups: classic (12 cases) and pleomorphic (15 cases), as defined in the World Health Organization classification. All tumors had an immunophenotype compatible with MCL, were positive for cyclin D1, and carried the t(11;14). Twenty-four cases had complex karyotypes with 3 or more chromosomal abnormalities in addition to the t(11;14). In classic blastoid MCL, abnormalities of chromosomes 13, 18, and 8 were most common. In pleomorphic blastoid MCL, abnormalities of chromosomes 13, 17, and 3 were most frequent. Chromosome 22 abnormalities were detected exclusively in the pleomorphic group. Tumors in which the neoplastic cells showed prominent nucleoli had a significantly higher frequency of chromosome 17 abnormalities (P = 0.03). We conclude that blastoid MCL tumors often show complex cytogenetic aberrations. Some abnormalities correlate with morphologic features, suggesting that morphologic variants of blastoid MCL may arise via different molecular pathways.