Reversible follicular lymphoid hyperplasia related with dasatinib: first case report from Turkey

Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder characterized by the presence of a cytogenetic abnormality, the Philadelphia (Ph) chromosome. BCR-ABL tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of chronic myeloid leukemia (CML). Patients who respond to treatment achieve a near-normal life expectancy. In this case report, we present the first case from Turkey of reversible follicular lymphoid hyperplasia (FLH) related to the use of a second-generation TKI, dasatinib. A peripheral blood specimen was evaluated by double-fusion fluorescence in situ hybridization (FISH) for cytogenetics and by quantitative RT-PCR (qPCR) for BCR-ABL1 mRNA transcripts. The cervical lymph node biopsy tissue was embedded in paraffin and sectioned following routine methods after fixation in neutral buffered formalin. Immunohistochemical staining was applied for further evaluation. A 64-year-old male CML patient with complete cytogenetic response (CCyR) and major molecular response (MMR) presented with lymphadenopathies accompanied by mild lymphocytosis following 3 months of dasatinib treatment. The patient was diagnosed with FLH. After termination of dasatinib, the lymphadenopathies regressed during follow-up. FLH should be considered a rare side effect of dasatinib. A watch and wait strategy following dasatinib treatment termination would be suitable.