Checkpoint Inhibitor-Induced Raynaud's Phenomenon, Hypothyroidism, and Pneumonitis in Head and Neck Cancer: A Case Report.

The inhibition of the checkpoint receptor-ligand system has become a therapeutic target in the treatment of solid malignancies in immuno-oncology. Increased attention has been given to immune-related adverse events (irAEs) associated with the use of checkpoint inhibitors. Multiple irAEs may occur in a single patient. Here, we report a unique case in which Raynaud's syndrome was associated with two other autoimmune complications, hypothyroidism and pneumonitis. The patient was a 48-year-old Caucasian man whose complaints started with a sore throat. Ultrasound and CT revealed left cervical lymph node enlargement. Aspiration cytology showed infiltrating human papillomavirus (HPV)-positive squamous cell cancer. As the outcome of surgery was uncertain, neoadjuvant chemotherapy and irradiation were successfully applied. Later, CT revealed tumor relapse. Nivolumab therapy was initiated, and a total of 21 cycles were administered to the patient. Three months after the initiation of nivolumab, new-onset Raynaud's phenomenon (RP) developed. No systemic connective tissue disease could be identified. RP improved following oral pentoxifylline treatment. Later, hypothyroidism and pneumonitis developed, both of which were easily controlled. Eventually, significant tumor progression occurred despite nivolumab treatment, and Cetuximab was administered; however, the patient died. It has been established that if two or more irAEs develop in the same patient, one of these irAEs is more likely to be autoimmune rheumatic in nature. It is very important to detect these side effects in time; physicians must be familiar with their appropriate treatment because all side effects may be essential to the patient's survival.