Abstract: This article reports a case of a 52-year-old female who presented with a progressively enlarging left neck mass and had an 8-year history of targeted therapy for malignant small intestinal gastrointestinal stromal tumor (GIST).Imaging studies revealed a left thyroid lobe nodule suspicious for malignancy.The patient underwent left thyroid lobectomy with isthmusectomy and central lymph node dissection.Postoperative pathology,confirmed by immunohistochemical analysis,established the diagnosis of metastatic GIST to the thyroid.This case highlights the importance of comprehensive differential diagnosis between primary and metastatic thyroid tumors in patients with a history of malignancy,underscoring the need for careful therapeutic decision-making.

Key words: small intestinal gastrointestinal stromal tumor; thyroid gland; metastasis