Thyroid Cancer With Cutaneous Metastases.

Objectives: Thyroid carcinoma with cutaneous metastases is a rare clinical finding. Cutaneous metastases from thyroid carcinoma have been associated with a poor prognosis, but these data are limited to case reports. The exact mechanism of cutaneous metastases from thyroid carcinoma is not clear. Our study aims to report the demographic, clinical, and histologic findings of patients with cutaneous metastases from thyroid carcinoma. Methods: A review was conducted using the Medline/PubMed, Cochrane, and Scopus databases to review literature from inception to May 2023. Data extracted included patient age at diagnosis of cutaneous metastases, patient sex, thyroid carcinoma histotype, location of metastases, the time interval between diagnoses of thyroid carcinoma and cutaneous metastases, and overall survival (OS) from the time of cutaneous metastases. Results: One hundred thirty-six patients were identified and 75 were female. The most common types of thyroid carcinoma with cutaneous metastases were papillary (47.79%), followed by follicular (30.15%), and medullary (11.03%). In addition, 11 cases of anaplastic carcinoma, 2 cases of oncocytic carcinoma, and 2 cases of poorly differentiated thyroid carcinoma were reported. The average age at diagnosis of cutaneous metastases was 63.13 years, and the average time interval between the diagnoses of primary thyroid carcinoma and cutaneous metastases was 48.27 months. The most common location of metastases was the scalp (n = 48). Other common locations included the neck, chest, and face. The OS after diagnosis of metastases was only available in 34 patients with an average of 13.07 months. Of these 34 cases, 10 were medullary, 10 were papillary, 9 were anaplastic, and 5 had follicular carcinoma. Conclusions: This study represents an up-to-date review of the cases of thyroid carcinoma with cutaneous metastases. While cutaneous metastasis remains a rare finding, one needs a high index of suspicion, and their presence portends a poor prognosis.