Venotoclax associated hypothyroidism in a patient with acute myeloid leukemia

Introduction Venetoclax is a selective inhibitor of BCL2. While its combination with hypomethylating agents (HMAs) is associated with manageable side effects, thyroid dysfunction has not been previously reported. Case Report We present the case of a 62-year-old female with relapsed/refractory AML who was treated with azacitidine and venetoclax. Within a month, she developed hypothyroidism with elevated TSH (42.86 µIU/mL) and low FT4 (0.34 ng/dL). Baseline thyroid function tests were normal. Management & Outcome Ultrasonography showed a diffusely enlarged thyroid gland, and thyroid autoantibodies were negative, ruling out autoimmune thyroiditis.Thyroid hormone replacement therapy was initiated, normalizing thyroid function, while venetoclax was continued due to its efficacy. Discussion This case highlights a rare, non-autoimmune thyroid dysfunction associated with venetoclax. The absence of autoantibodies suggests a mechanism unrelated to autoimmunity, emphasizing the need for thyroid monitoring during venetoclax therapy.