OCCULT THYROID-CARCINOMA

Occult thyroid carcinoma, defined here as an impalpable thyroid carcin oma that is generally smaller than 1.0 cm, is a frequent finding in th e general population. Its prevalence varies according to the geographi cal location, type and intensity of the pathological examination and h istory of exposure to ionizing radiation. It is found at all age group s, but is more frequent after the age of 40 years, There is no gender difference in the frequency of occult thyroid carcinoma found at autop sy or ire surgical specimens removed fos other diseases, Most commonly , it is of the papillary type, and can Pre classified as sclerosing no n-encapsulated (SNE), non-sclerosing encapsulated (NSE) and non-sclero sing non-encapsulated (NSNE) carcinoma. NSNE may be ana early stage Th e tumor progression, although most of the sclerosing tumors remain cli nically silent throughout life, Occult thyroid carcinoma that is not m etastatic has a much better prognosis than clinically apparent thyroid carcinoma; few tumors recur and almost no one dies of cancer, However , thyroid capsular invasion and lymph node metastases may occur with o ccult thyroid carcinomas, and distant metastases which may be fatal ha ve been reported. Nodal metastases may be the presenting manifestation . Ultrasonography and scintigraphy can detect impalpable lesions, whil e fine-needle aspiration biopsy is the best way to assess their malign ant nature Age over 45, male gender; aggressive pathological variant, multicentricity, local invasion, nodal metastases, distant metastases and history of exposure to ionizing radiation favor total ablation. Ot herwise, the extent of surgery should be individualized, but generally may be less than total thyroidectomy.