The term fetal Adenoma is used for

Adenomas of the thyroid are typically discrete, solitary masses, derived from follicular epithelium, and hence they are also known as follicular adenomas. Clinically, follicular adenomas can be difficult to distinguish from dominant nodules of follicular hyperplasia or from the less common follicular carcinomas. In general, follicular adeno- mas are not forerunners to carcinomas; neveheless, shared genetic alterations suppo the possibility that at least of subset of follicular carcinomas arises in preexisting adeno- mas (see later). Although the vast majority of adenomas are nonfunctional, a small subset produces thyroid hor- mones and causes clinically apparent thyrotoxicosis. Hormone production in functional adenomas (