Lenvatinib as a Promising Treatment Option for Unresectable Hürthle Cell Carcinoma: A Case Report.

Hürthle cell carcinoma (HCC) of the thyroid gland generally has a more aggressive clinical course than other differentiated thyroid cancers (DTCs), and it is associated with a higher rate of distant metastases. In this case report, we highlight the importance of tyrosine kinase inhibitors as a management strategy for unresectable DTCs. Surgical management is challenging if the cancer is locally advanced and invades major neck structures with an increased risk of recurrence. Tyrosine kinase inhibitors (TKIs) are used in the case of advanced disease, especially in unresectable, radio-iodine refractory and with metastatic status. Lenvatinib, a TKI, used as the first line of treatment, plays a key role in improving prognosis and survival rates among patients. A 37-year-old gentleman presented with a locally advanced and widely metastasized case of large Hürthle cell carcinoma encasing the left carotid sheath and the left recurrent laryngeal nerve. Fine needle aspiration cytology (FNAC) was suggestive of HCC and a positron emission tomography-computed tomography (PET-CT) scan revealed metastases to the lungs and spine. In this case, lenvatinib was used to prevent the proliferation of malignant cells and the neovascularization of the tumor. This clinically translated into a good response in a high disease burden scenario. The patient showed positive results with lenvatinib therapy with a progression-free duration of 30 months and a reduction in the size of cancer. This case report describes the use of lenvatinib for the treatment of a large unresectable locally advanced and widely metastasized case of Hürthle cell carcinoma in a young gentleman with a response profile.