Large thigh and buttock muscle metastases as the initial manifestation of follicular thyroid cancer.

Follicular thyroid carcinoma (FTC) is the second most common thyroid malignancy after papillary thyroid carcinoma (PTC). It has a greater tendency than PTC to metastasize to distant organs such as the lung and bone. FTC metastasis to skeletal muscle is extremely rare. Here, we report a 65-year-old woman with large thigh and buttock muscle metastases as the first manifestation of FTC.