Ultrasonographic Findings and Prognosis of Metastases to the Thyroid Gland.

Metastases to the thyroid gland (MTT) are uncommon in clinical practice. The ultrasound (US) features are easily confused with primary thyroid malignancy, Hashimoto's thyroiditis, and other thyroid diseases. Therefore, this study aimed to assess the role of US and analysis of prognosis of MTT. A total of 45 patients with MTT in the database between July 2009 and February 2022 at the Fujian Cancer Hospital were reviewed. US examinations were performed only on 20 patients, who were finally included in our study. Among the 20 patients, nine were male, and eleven were female. According to US characteristics, metastases to the thyroid gland were divided into nodular and diffuse types (17 and 3 cases, respectively). Three lesions (17.6%) had circumscribed margins, and 14 (82.4%) were uncircumscribed. Three lesions (17.6%) were regular in shape, and 14 (82.4%) were irregular. Nine metastases (52.9%) were a taller-than-wide shape, and eight (47.1%) were not a taller-than-wide shape. Ten lesions (58.8%) had rich vascularity, and seven (41.2%) had absence/not rich vascularity. The mean overall survival (OS) from the time of MTT diagnosis was 22 months (95% confidence interval: 5.95-38.05). The 1-, 3-, and 5-year OS after metastasis was 68.1%, 25.5%, and 17%, respectively. The prognosis of MTT was poor, which is closely related to the characteristics of the primary tumor and metastatic disease. The US findings and US-guided core needle biopsy may be useful in diagnosing MTT in patients with a history of the malignant tumors.