A study submitted to Research Square has revealed that even though uveal metastases (UM) originating from thyroid neoplasms are relatively rare, they might still threaten the eyesight of every patient with thyroid cancer. The study suggested that physicians should be alert and consider the possibility of UM if patients report ocular symptoms, a neck mass, or a prior history of thyroid malignancies.
Thyroid cancer is the most common type of endocrine tumor, and its incidence has increased 3 fold worldwide over the past 40 years. In 2021, approximately 43,800 new cases were reported in the United States, with a higher prevalence in women than men. The mean age at diagnosis is typically around 40 years old, suggesting that the younger population is affected mainly by TC compared to other types of cancers.
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Primary thyroid cancers are categorized into 4 types, including well-differentiated epithelial thyroid cancers (papillary thyroid cancers (PTC) and follicular thyroid cancers (FTC) ), poorly differentiated epithelial thyroid cancers, medullary thyroid cancers (MTC), and rare types such as sarcomas and lymphomas. PTC and FTC account for 95% of thyroid cancer cases, with PTC being the most common type, with regional lymph node metastasis occurring in 30% to 40% of cases and distant metastases occurring in 1% to 4% of patients.
The lungs and bones are the most common sites for distant metastases with rare intraocular involvement. However, up to 10% of individuals with metastatic cancers may develop uveal metastases. Several diagnostic techniques, such as ultrasonography, enhanced depth imaging, optical coherence tomography, fluorescein angiography, multicolor imaging, and indocyanine green angiography, are used to examine specific features of choroidal melanoma.
The case report analyzed Web of Science, Medline, and Scopus databases for cases reporting uveal metastasis originating from a thyroid neoplasm. The research team searched and screened articles published in any language from the beginning until November 2022. The quality of the included studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Case Reports.
Study results identified 46 cases, with the mean age of patients at the time of UM diagnosis being 56.5 years. Of the 46 cases, 16 cases (34.78%) were reported in the elderly patients, while the male patients accounted for 26 (56.52%) cases. Additionally, 16 cases occurred in the right eye, 19 in the left, and 11 in both eyes. Among all cases, 39 (84.78%) had choroidal involvement. The most frequently reported type of thyroid cancer among patients was papillary carcinoma (16/46), followed by follicular (15/46) and medullary (10/46) carcinomas of the thyroid.
“In our study, 84% of patients had choroidal involvement, the most commonly involved part, followed by the iris and ciliary body. Our findings are similar to previous studies,” the authors highlighted. The authors acknowledged several limitations in the study, including the small population and incomplete reporting in multiple cases.
Reference
Abdollahi M, Nateghian H, Fazlinejad N, et al. Uveal metastasis arising from thyroid neoplasms: a systemic review of case reports. Research Square. Published online February 23, 2023. doi: 10.21203/rs.3.rs-2294147/v1
