الفهرس 
Development of The Thyroid Gland and Its AnomaliesOnly 14 pages are availabe for public view
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Abstract
W
ith modern imaging techniques, thyroid nodules are found in up to 50% of the thyroid glands examined and 4% of the general population present with a palpable nodule.
Solitary thyroid nodule can be either:
1. Dominant nodule in multinodular goiter.
2. Thyroid cyst.
3. Focal thyroidites.
4. Neoplasms (benign & malignant).
5. Autonomous nodule.
However, only a small fraction of these lesions harbor a clinically relevant malignancy and hence criteria need to be defined for which nodules need further investigations.
Due to its high sensitivity and specificity, FNA biopsy is the procedure of choice for the exclusion of a thyroid malignancy and it should be performed after thyroid dysfunction has been excluded by measuring a TSH serum level.
While FNA biopsy results permit a definitive diagnosis in about 70% of the patients, microfollicular lesions are found in 20% presenting the physician with the choice of operating on patients with roughly about 5% risk follicular cancer.
Although the volume and progression of benign nodules can be reduced in some patients by T4 therapy, this requires, by definition, the suppression of endogenous TSH levels therapy including subclinical hyperthyroidism.
Most patients with thyroid cancer can be cured. However, both initial treatment and follow up should be individualized according to prognostic indicators and thereafter according to any evidence of disease.
Management of these patients is multidisciplinary. Primary treatment based on surgery in all cases, and on RAI in those with high risk of recurrence or death. External radiation beam therapy is given only to a few selected cases.
Follow-up relies on both non-specific methods (clinical examination, ultrasonography) and on specific methods (serum Tg determination, RAI total body scanning), their combined use permits the early detection of persistent and recurrent disease.
There are still clinical and histological difficulties in the initial diagnosis of MTC. MTC is often revealed by a non-specific nodule, pre-operatively detected by an elevated serum calcitonin level and confirmed at histology.
Physicians must always be aware of the possibility of familial forms, which present in >25% of cases. RET mutations are encountered in the three inherited forms of MEN2 and correlate more or less tightly with phenotype.
Multimodality therapy is usually required to treat ATC of these rare tumors. Current investigations hold promise for better therapies in the future.
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