Diagnostic problems in differentiated carcinomas of the thyroid.

In this review article we consecutively address the following issues: differential diagnosis of follicular adenomas and minimally invasive follicular carcinomas, with a special emphasis on the hyalinizing trabecular tumours; differential diagnosis of benign and malignant papillary lesions; individualization of the variants of papillary carcinoma that carry a guarded prognosis; differential diagnosis of differentiated thyroid carcinomas exhibiting foci of other types of thyroid carcinoma, namely mucoepidermoid and poorly differentiated carcinoma; and, finally, the diagnostic problems raised by the so-called mixed medullary-follicular carcinomas.