Thyroid often carcinomas, although cancer can occur in any tissue that the thyroid consists of, including cancer of C-cells and lymphomas. Cancers from other sites also rarely lodge in the thyroid. Radiation of the head and neck presents a risk factor for thyroid cancer, and cancer is more common in women than men, occurring at a rate of about 2:1. In most cases, thyroid cancer presents as a painless mass in the neck. It is very unusual for thyroid cancers to present with other symptoms, although in some cases cancer may cause hyperthyroidism. Most malignant thyroid cancers are papillary, followed by
Computed tomography of the thyroid hyperparathyroidism. Ectopic parathyroid adenoma is rare. The third and fourth pharyngeal pouches represent the embryological origin of the parathyroid tissues, and ectopic parathyroid adenoma can ultimately develop anywhere along their migration course. In a large retrospective study of patients with primary hyperparathyroidism, PA was detected in the intra-thyroid location in 0.7 % of cases. In another retrospective analysis of 202 patients with ectopic PA, intra-thyroidal location was found in 18 % of the cases. Intra-thyroid parathyroid adenomas mimic thyroid nodules in CT scans and may even show uptake on a thyroid iodine scan. Correlation with laboratory workup, including measurement of