SMZL : Genetic Features
Splenic Marginal Zone Lymphoma (SMZL) - Genetic Features: Loss of heterozygosity related to del 7q32 is found in about 40% of SMZL cases and it appears to be an adverse prognostic indicator. These patients show more frequent tumor progression. Gain of 3q has been reported in 10-20% of cases. Deletion of 17p13, the site of TP53, is seen in 3-17% of cases and is associated with adverse outcome. Immunoglobulin heavy-chain variable region (IgVH) shows somatic mutations in about 50% of cases.
Next-generation sequencing data on SMZL has shown somatic mutations in NOTCH2 and related genes involved in marginal zone differentiation. About 20% of cases show recurrent mutations in KLF2 - a transcription factor involved in B-cell differentiation.
The image shows diffuse involvement of the red pulp in SMZL. There is infiltration of cords as well as sinuses by neoplastic cells - both marginal zone cells with pale cytoplasm as well as rare centroblasts or immunoblasts.