A case of spindle cell carcinoma of the tongue metastasized to the thyroid gland

Spindle cell carcinoma is a rare malignant tumour that shows biphasic proliferation of squamous cell carcinoma components and sarcomatoid components of spindle-shaped cells in the same tissue. In addition, cases that a malignant tumour of the head and neck region metastasizes to the thyroid gland are extremely rare. We report an extremely rare case that spindle cell carcinoma of the tongue metastasized to the thyroid gland. A 59-year-old female presented with a polypoid mass in the right margin of the tongue. Based on histopathological diagnosis of spindle cell carcinoma of clinical staging II, a partial glossectomy was performed. Thyroid mass appeared at 5 months after the surgery. She was diagnosis with thyroid gland cancer and a total thyroidectomy was performed. A histopathological diagnosis revealed thyroid gland metastasis. However, a thyroid tumour recurred in the neck at 4 months after the thyroid surgery. The tumour was untreatable, and the patient expired 13 months after the primary resection.