Spontaneous pneumothorax is rarely associated with cancer. We describe a 73 year old man who presented with recurrent tumor in the right neck, mediastinal lymphadenopathy and bilateral pulmonary nodules after thyroidectomy. He was treated with lenvatinib and presented with bilateral pneumothoraces. Anaplastic thyroid cancer is an aggressive subtype of thyroid cancer that has limited response to cytotoxic chemotherapy and poor prognosis. Recent reports show that targeted therapy with a multiple receptor tyrosine kinase inhibitor, lenvatinib, may have improvement in progression-free survival, but rarely pneumothorax has been reported in those with lung metastases. Various mechanisms have been postulated, but necrosis of pulmonary lesions and/or subpleural micrometastases leading to bilateral pleural defects likely resulted in the development of pneumothoraces for our patient.