ABSTRACT
Follicular carcinoma (FTC) is a relatively uncommon type of differentiated thyroid carcinoma. Guidelines have often dealt with FTC and papillary thyroid cancer as a single disease. Over the last decade, however, a better understanding of these two types of thyroid cancer indicates that they cannot be analysed together.
Neither ultrasonography nor fine-needle aspiration cytology can provide a clear distinction between FTC and follicular adenoma. New molecular diagnostic techniques may be used to identify a subpopulation of follicular neoplasms with a low probability of being malignant.
Diagnostic surgery—usually hemithyroidectomy- is recommended for most thyroid follicular lesions without a certain preoperative diagnosis. If FTC is diagnosed most—perhaps not all- patients will require a completion thyroidectomy.
While widely invasive FTC usually does not pose diagnostic or therapeutic doubts, consensus on the diagnosis of non-invasive follicular lesions is still lacking.
Prognosis of FTC is mostly dependent on local invasion and distant metastasis that, in turn, correlate with tumor size.
Declaration of interest
M. Renard received a research grant and took part in the CITHY study sponsored by Diaxonhit (France). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.