THYROID CANCER
Definition
Thyroid cancer is a disease in which the thyroid cells become abnormal, grow uncontrollably, and form tumors. Thyroid cancers are grouped into four types, based on how the cell appears under the microscope. If left untreated, the cancer can spread to other parts of the body.

SUBCLINICAL THYROID DISEASE
Subclinical thyroid dysfunction is defined as an abnormal serum thyroid-stimulating hormone level (reference range: 0.45 to 4.50 [micro]U per mL) and free thyroxine and triiodothyronine levels within their reference ranges.

SCREENING FOR THYROID DISEASE
LF, a 50-year-old woman, requests a "thyroid blood test." You review the symptoms of hypothyroidism and hyperthyroidism with her and find that she has none of them. She still is concerned because "a doctor on television said all women should have this test."

THYROID FUNCTION TESTS
Definition
Thyroid function tests are blood tests used to evaluate how effectively the thyroid gland is working. These tests include the thyroid-stimulating hormone test (TSH), the thyroxine test (T4), the triiodothyronine test (T3), the thyroxine-binding globulin test (TBG), the triiodothyronine resin uptake test (T3RU), and the long-acting thyroid stimulator test (LATS).

PAPILLARY THYROID CARCINOMA
Papillary thyroid carcinoma is the most common type of thyroid malignancy. The minor occurs largely in adults, usually those between the ages of 20 and 50 years; the female-to-male ratio is 4:1. Papillary thyroid carcinoma is also the most common pediatric thyroid malignancy.

THYROID DISEASE IN CHILDREN
During embryogenesis, epithelial cells on the pharyngeal floor thicken to form a diverticulum. This diverticulum elongates, and the primordial thyroid cells migrate caudally until they fuse with the ventral aspect of the fourth pharyngeal pouch, at about the fourth gestational week

THYROID ULTRASOUND
Definition
Thyroid ultrasound is an imaging technique used for diagnosing suspected thyroid disease. It uses harmless, high frequency sound waves to form an image. The sound waves are reflected by thyroid tissue to form a picture of internal structures. It is not invasive and involves no radiation.

BLACK THYROID - PATHOLOGY CLINIC
A finding of a black thyroid gland (figure 1) is unusual and disconcerting. Among the possible causes of black thyroid are minocycline-induced pigmentation, hemochromatosis, ochronosis, mucoviscidosis, ceroid storage disease, bruising, and hemorrhage. In addition, medullary thyroid carcinomas have been reported to produce melanin in rare cases.