Bilateral pneumothorax in a patient with anaplastic thyroid carcinoma and lung metastasis during lenvatinib therapy: a case report.

The prognosis of anaplastic thyroid carcinoma (ATC) is very poor. In most patients, ATC presents with cervical lymph node metastasis, and more than 40% of patients have distant metastasis at the time of diagnosis. Lenvatinib, a multi-targeted tyrosine kinase inhibitor, is a novel drug that has antitumor effects on radioactive iodine-refractory papillary cancer and anaplastic cancer. The development of bilateral pneumothorax during targeted therapy is very rare in patients with thyroid cancer. We recently encountered a case of bilateral pneumothorax in a patient with ATC and lung metastasis during lenvatinib therapy. The patient underwent video-assisted thoracoscopic surgery (VATS) in both the lungs because the pneumothorax continued to aggravate even after the insertion of chest tubes. Clinicians need to be aware that the development of pneumothorax is a possibility during lenvatinib therapy for ATC and lung metastasis. The case is reported herein, along with a review of relevant literature.