Dasatinib-Induced Gynecomastia: A Case Report

Gynecomastia, the abnormal enlargement of male breast tissue, is a rare side effect associated with dasatinib. This drug is used in the treatment of chronic myeloid leukemia (CML). We present a case of dasatinib-induced gynecomastia in a 52-year-old gentleman with CML who developed bilateral breast enlargement and tenderness after approximately four months of dasatinib treatment. The patient's hormonal profile was within normal limits, including testosterone, estradiol, prolactin, and follicle-stimulating hormone levels. While the exact pathophysiology remains unclear, it is postulated that dasatinib's inhibition of various kinases, including src family kinases and receptor kinases, may contribute to developing gynecomastia. The reported incidence of dasatinib-induced gynecomastia is low, and the onset of symptoms can vary widely. Management strategies for dasatinib-induced gynecomastia are not well-established, but options include androgen support, tamoxifen, or switching to an alternative tyrosine kinase inhibitor. This case report highlights the importance of monitoring patients on dasatinib therapy for developing gynecomastia and other hormonal abnormalities. Clinicians should educate the patients about the possibility of this potential adverse effect, emphasizing the need to report any symptoms indicative of low testosterone syndromes. Further research is warranted to better understand the underlying mechanisms, risk factors, and optimal management strategies for dasatinib-induced gynecomastia.