anaplastic thyroid carcinoma

(redirected from undifferentiated thyroid carcinoma)

anaplastic thyroid carcinoma

The most aggressive of all thyroid malignancies, which accounts for only 2–5% of thyroid carcinomas but 40% of thyroid cancer-related deaths. The typical history is of a rapid increase in size of a long-standing cold thyroid nodule in an elderly patient; it is more common in iodine-deficient geographic regions and in a background of prior thyroid pathology (e.g., goitre or thyroid cancer); up to 80% have a history of well- (papillary, follicular) or poorly differentiated thyroid carcinoma. Local invasion (e.g., trachea, oesophagus) is common.

Clinical findings
Hoarse voice, cough, haemoptysis, tracheal obstruction; physical exam may reveal nodules in thyroid.

Lab
Thyroid function is usually normal.

Diagnosis
Biopsy.
 
Management
Generally palliative; 50% are inoperable at the time of diagnosis; surgery, radiation and chemotherapy are essentially useless.

Prognosis
Anaplastic carcinoma is an aggressive disease with early metastases in lung (50% of cases), bone and brain; median survival is 4­–6 months.
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Among these, there were 17,125 cases with papillary thyroid carcinoma (PTC), 253 with follicular thyroid carcinoma (FTC), 239 with medullary thyroid carcinoma (MTC), 25 with anaplastic/ undifferentiated thyroid carcinoma, and 103 with two pathologic types of thyroid carcinoma.
(5) There are three main types of thyroid carcinoma: Well-differentiated thyroid carcinoma, poorly differentiated thyroid carcinoma and undifferentiated thyroid carcinoma. The large majority of these malignancies are represented by differentiated thyroid carcinomas, such as papillary thyroid carcinoma and follicular thyroid carcinoma.
Histologically, undifferentiated thyroid carcinomas show a variety of patterns, from sheet-like, storiform, fascicular, angiomatoid, and meningothelial to solid, exhibiting extensive lymph-vascular invasion.
(16) Fortunately, only 2% to 5% of thyroid cancers are anaplastic or undifferentiated thyroid carcinoma. This lesion is associated with very poor survival, usually measured in months.
Undifferentiated Thyroid Carcinomas (UTC) are highly malignant tumours that histologically appear wholly or partially composed of undifferentiated cells that exhibit immunohistochemical or ultra-structural features indicative of epithelial differentiation.
(186-191) However, CD44v6 expression was also demonstrated in benign lesions and poorly differentiated or undifferentiated thyroid carcinomas at a lower rate of expression.

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