The (11;14)(q13;q32) translocation in multiple myeloma - A morphologic andimmunohistochemical study

We identified 24 cases of multiple myeloma with the t(11:14)(q13;q32). In 2 2 cases, the t(11;14)(q13;q32) was part of a complex karyotype, and in 2 ca ses it was an isolated abnormality. All patients had clinical and laborator y features consistent with multiple myeloma. The median degree of plasma ce ll involvement in the bone marrow was 60%, and in 10 cases, the plasma cell s had a lymphoplasmacytoid appearance. Of the 24 cases, 21 had intermediate or high proliferative rates based on labeling index studies. Immunohistoch emical studies performed on all bone marrow biopsy specimens showed strong cyclin D1 nuclear positivity in 19 cases. There also was strong cyclin D1 n uclear positivity found in 6 of 30 additional cases without the t(11;14)(q1 3;q32) demonstrated by routine cytogenetics. The t(11;14)(q13;q32) in multi ple myeloma results in over-expression of the cyclin D1 protein, which can be demonstrated by immunohistochemical stain. The cyclin D1 stain results i n the additional cases of multiple myeloma suggest that the t(11;14)(q13;q3 2) may be more common than previously thought and may be missed by routine cytogenetics, particularly if the proliferative rate is low.