Anaplastic Thyroid Carcinoma

Epidemiology and Etiology:

· Older

· Mean age 65 y

· Concurrent or past thyroid disease (80%)

· History of thyroid lesions:

· Multinodular goiter (50%)

· Differentiated CA (20%)

· Concurrent differentiated thyroid tumour (20-30%)

· Papillary CA often

Common sites:

·

Gross features:

·

Histologic features:

· Highly anaplastic cells

· Large, pleomorphic giant cells maybe

· Occasional osteoclast-like multinucleate giant cells

· Spindle cells maybe

· Mixed spindle and giant cells maybe

· Small cells similar to small cell CA maybe

· Extension into surrounding tissues frequently

· Lymphovascular invasion frequently

·

Immunophenotype:

Marker:	Sensitivity:	Specificity:
Thyroglobulin (neg)
Cytokeratin	Majority

Molecular features:

· P53 loss

Other features:

· Aggressive

· Mortality rate approaching 100%

· Metastatic at diagnosis usually

· Rapidly enlarging

· Compressive symptoms

References:

· Kumar V, Fausto N, Abbas A. Robbins & Cotran Pathologic Basis of Disease, Seventh Edition. 7th ed. Saunders; 2004.