How to define follicular thyroid carcinoma?

Abstract

The appropriate diagnosis of follicular thyroid carcinoma (FTC) still depends on its histological discrimination from follicular adenoma (including the distinction of benign from malignant oncocytic variants), papillary thyroid carcinoma (particularly from the follicular variants) and poorly differentiated thyroid carcinoma. The use of immunohistochemical markers contributed only marginally to better defining FTC. The introduction of the micro array technique, however, may offer the possibility of getting a better insight into the natural history, as well as predicting the clinical course, of a given thyroid nodule. This review attempts to recapitulate common standards in the diagnosis of FTC, to summarise current molecular data available to distinguish FTC from other benign and malignant tumours and, finally, to outline future perspectives to define FTC on its specific genetic features.

A molecular expression signature distinguishing follicular lesions in thyroid carcinoma using preamplification RT-PCR in archival samples

“…3 Because papillary structures may occasionally be found in follicular adenoma and follicular thyroid carcinoma, the diagnosis of papillary thyroid carcinoma ultimately depends on its nuclear features, that is ground glass appearance, irregularity of nuclear contours, grooves and pseudo-inclusions. 4 The diagnosis of papillary thyroid carcinoma does not simply depend on the presence of these nuclear features but the extent to which they are present in 'a significant proportion of the neoplasm'. 3 The lack of appreciation of the diagnostic features of a papillary thyroid carcinoma, particularly in encapsulated tumours, may either lead to the misdiagnosis of a follicular thyroid carcinoma or that of a benign follicular adenoma.…”

“…3 The lack of appreciation of the diagnostic features of a papillary thyroid carcinoma, particularly in encapsulated tumours, may either lead to the misdiagnosis of a follicular thyroid carcinoma or that of a benign follicular adenoma. 4 The follicular variant of papillary thyroid carcinoma is found in 9-22.5% of patients with a papillary thyroid carcinoma. 1 Follicular variant of papillary thyroid carcinoma is composed predominantly by follicles, which are lined by cells that have the nuclear features of papillary thyroid carcinoma.…”

Ectopic Thyroid Presenting as a Submandibular Mass

“…Parameters to differentiate between primary benign and malignant neoplasia of ectopic thyroid tissue are the same as used in primary tumors. To diagnose thyroid follicular carcinoma, vascular invasion and/or capsular rupture should be identified [17]. To differentiate from thyroid papillary carcinoma, nuclear characteristics should be excluded (ground-grass appearance, irregularity of nuclear contours, grooves, pseudoinclusions) [17].…”

Expression of ARE-binding proteins AUF1 and HuR in follicular adenoma and carcinoma of thyroid gland

“…Papillary thyroid carcinoma (PTC) which is the most frequent diagnosed type of thyroid cancer is relatively easy to discriminate by employment of FNA biopsy. However in case of follicular thyroid carcinoma (FTC), follicular variant of papillary thyroid carcinoma (FVTC), and follicular thyroid adenoma (FA) definitive distinction of FA from FVTC, low-grade or well-differentiated FTC may be difficult or even impossible [16,17,18].…”