[Thyrotoxicosis induced by immune checkpoint inhibitor therapy for unresectable hepatocellular carcinoma:a case report].

A 65-year-old woman was diagnosed with hepatocellular carcinoma (HCC) in February 20XX-1. Following three cycles of transarterial chemoembolization (TACE) for recurrent HCC, combination therapy with atezolizumab and bevacizumab (Atezo+Beva) was initiated in February Y, 20XX. Eight days after treatment initiation (Y+8), the patient developed a fever and generalized malaise. By day 14 (Y+14), her symptoms worsened, prompting a visit to her primary physician, where a fever of 39°C was recorded. However, no hypoxemia was observed, and she was sent home. The following day (Y+15), she developed dyspnea and hypoxemia (SpO₂ in the 80% range), and chest computed tomography (CT) revealed a hilar central alveolar infiltration. She was subsequently admitted to her previous hospital. Comprehensive evaluation led to a diagnosis of congestive heart failure associated with thyrotoxicosis. According to the IMbrave150 study, thyroid dysfunction occurs in 13.4% of patients receiving Atezo+Beva therapy;however, cases classified as Common Terminology Criteria for Adverse Events Grade 3 or higher, requiring hospitalization, are extremely rare, with an incidence of only 0.3%.