Thyroid cancer is a thyroid neoplasm that is malignant. It can be treated with radioactive iodine or surgical resection of the thyroid gland. Chemotherapy or radiotherapy may also be used.
Thyroid cancers can be classified according to their histopathological characteristics. The following variants can be distinguished (distribution over various subtypes may show regional variation):
- Papillary thyroid cancer (75% to 85% of cases ) - often in young females - excellent prognosis
- Follicular thyroid cancer (10% to 20% of cases
- Anaplastic thyroid cancer (Less than 5% These types have a more favorable prognosis than the medullary and undifferentiated types.
- Papillary microcarcinoma is a subset of papillary thyroid cancer defined as measuring less than or equal to 1 cm. The highest incidence of papillary thyroid microcarcinoma in autopsy series was reported by Harach et al. in 1985, who found 36 of 101 consecutive autopsies were found to have an incidental microcarcinoma. Michael Pakdaman et al. report the highest incidence in a retrospective surgical series at 49.9% of 860 cases. Management strategies for incidental papillary microcarcinoma on ultrasound (and confirmed on FNAB) range from total thyroidectomy with radioactive iodine ablation to observation alone. Harach et al. suggest using the term "occult papillary tumor" to avoid giving patients distress over having cancer.It was Woolner et al. who first arbitrarily coined the term "occult papillary carcinoma" in 1960, to describe papillary carcinomas ≤ 1.5 cm in diameter.
From the 1940s to 1960s, external, low-dose radiation to the head and neck during infancy and childhood was used to treat many benign diseases.
This type of therapy has been shown to predispose persons to thyroid cancer. The younger the patient was at time of exposure, the higher the risk of developing cancer.
Another cause may be due to high-dose irradiation to the head and neck. Patients with Hodgkin lymphoma treated with mantlefield irradiation have an increased risk of developing thyroid cancer, although hypothyroidism is more likely.
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Last Updated: Sep 15, 2014