Sorafenib-induced Thyroiditis in FMS-like Tyrosine Kinase 3-internal Tandem Duplication-mutated Acute Myeloid Leukemia

Correspondence To the Editor: Sorafenib is a novel, orally available inhibitor of multiple kinases. It has been used in relapsed and refractory FMS‑like tyrosine kinase (FLT)‑3‑positive acute myeloid leukemia (AML) in recent years with favorable outcomes. Thyroiditis and hypothyroidism as side effects have been reported in treatment on renal cell cancer. [1] Here, we report a case of FLT3‑internal tandem duplication (ITD)‑positive AML, who developed subacute thyroiditis during treatment with sorafenib. Thyroiditis was controlled with sorafenib withdrawal and the use of dexamethasone. No thyroid dysfunction was detected under follow‑up. Our experience shows that close monitoring of thyroid function is necessary in AML patients under sorafenib treatment. A 35‑year‑old female was diagnosed with FLT3‑ITD‑positive AML (AML‑5b). Routine blood examinations revealed white blood cell (WBC) count 104.9 × 10 9 /L, hemoglobin 46 g/L, platelet count 180 × 10 9 /L, and blast cells 50%. She was a hepatitis B virus (HBV) carrier with HBV‑DNA copies less than the minimum detection level (reference range: 0–1000 U/ml). Lamivudine was administered. She received induction chemotherapy as intra‑arterial (idarubicin 8 mg/m 2 on days 1–3 and cytarabine 100 mg/m 2 on days 1–5). On day 7 after induction chemotherapy, the bone marrow smear was rechecked. Bone marrow pro plus pre‑monocytes were 5% and minimal residual disease (MRD) was 0.27%. However, at 27 days after chemotherapy, a bone marrow examination showed that pro plus pre‑monocytes were 66%. She received the second cycle of chemotherapy with a dose‑reduced AAE (aclarubicin 20 mg, days 1–3; cytarabine 100 mg/m 2 , days 1–5; and etoposide 100 mg, days 1–3) plus sorafenib (400 mg bid, orally). The chemotherapy dose was reduced because the patient developed gastric hemorrhage. One month later, a routine bone marrow examination showed low myeloproliferation, 10% pro plus pre‑monocyte cells, and 1.79% MRD. On day 37 of sorafenib therapy, the patient felt a neck mass with pain and fever. She felt pain in the region of the thyroid, especially during swallowing with a pain scale score at 5; the neck mass enlarged quickly during the 1 st week; and her temperature was as high as 39°C. She stopped taking sorafenib by herself 2 days after neck pain was happened. was below the detection limit. Neck computed tomography (CT) with intravenous (iv) contrast showed thickening of both sides of the pharynx oralis and enlargement of both sides of the thyroid gland with unequal density [Figure 1a and 1b]. …