Contributor: Gordon K. Klintworth
The most common type of carcinoma in the thyroid gland  [carcinoma - thyroid gland] is a papillary carcinoma.  The tumor accounts for ~70% of thyroid carcinomas and it occurs primarily in iodine-deficient regions of the world. External radiation is another known etiological factor.  The tumor may occur in young individuals and presents with a visible or palpable nodule or as metastases in the regional lymph nodes in the neck following invasion of the lymphatic vessels. The neoplastic epithelium is present on the surface of papillae and psammoma bodies are common and are found in ~ 50% of cases. Papillary thyroid carcinoma has a relatively benign behavior. This tumor is uniquely associated with the ret/PTC oncogene.