Clonal analysis helps to differentiate aberrant thyroid tissue from thyroid carcinoma.

A rare case of multiple aberrant of thyroid tissues in the tongue and lymph nodes of the bilateral neck was studied by immunohistochemistry and molecular clonal analysis to determine whether these tissues represent aberrant ectopic thyroid or metastases of a thyroid carcinoma. The thyroid tissues in the tongue and lymph nodes were all of polyclonal origins, consistent with ectopic thyroid in the tongue and bilateral cervical lymph nodes, rather than malignant thyroid tissues. This case shows that molecular clonal analysis can be used to distinguish aberrant thyroid from metastases of thyroid carcinoma.