The background of the study. Most thyroid nodules are benign, but a few are cancers. Among the latter, most are thyroid cancers, but a few are cancers that have spread from of other organs. This study determined the characteristics and outcome in patients with nonthyroid cancers that had spread to the thyroid gland.
How the study was done and the results of the study. From 1985 to 2002, 1016 patients were operated on for malignant tumors of the thyroid at a single hospital in the United Kingdom. Fifteen patients (1.5 percent) had tumors that originated in other tissues. The initial sign of thyroid disease was a neck mass in 11 patients and difficulty swallowing in 2; the thyroid disease was detected by radiologic study in 1 patient and by surgery in 1.
The interval between the diagnosis of the primary tumor and the thyroid tumor ranged from 0 to 15 years; in five patients the thyroid tumor was the first manifestation of tumor. The primary tumor was a kidney cancer in four patients; one patient each had breast cancer, melanoma, lung cancer, colon cancer, cancer of the arm, uterine cancer, bladder cancer, cancer of unknown primary site, leiomyosarcoma, liposarcoma, and paraganglioma.
In nine patients, thyroid surgery revealed the nonthyroid cancer. Four of these patients had cancer in other organs, but were operated on because they had a large thyroid mass. Among the other patients, five had cancer elsewhere when they presented with the thyroid mass. Ten patients died 3 to 45 months after presenting with the thyroid tumor, and the remaining five were alive 3 to 84 months after thyroid surgery and chemotherapy.
The conclusions of the study. In a few patients who have a thyroid nodule the nodule is a tumor that originated in another organ.
The original article. Wood K, Vini L, Harmer C. Metastases to the thyroid gland: the Royal Marsden experience. Eur J Surg Oncol 2004;30:583-8.