Background
The inclusion of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) in the 4th edition of the World Health Organization (WHO) classification of endocrine tumors was carried out with the aim of sparing patients with the diagnosis of this subgroup of encapsulated follicular variant of papillary thyroid carcinoma with an indolent course from overtreatment as well as a burdensome cancer diagnosis. As a result, a reduction of papillary thyroid cancer (PTC) of 10–20 % is expected, particularly in Europe and North America.
Objective
This article provides a description of the diagnostic criteria for NIFTP and the presentation of further candidates for classification as thyroid neoplasms with uncertain/low malignant potential, such as minimally invasive follicular carcinoma and medullary carcinoma without a desmoplastic stromal reaction.
Material and methods
Determination of the biological behavior of these tumor entities based on internationally published literature and relevant guidelines on thyroid tumors.
Results and conclusion
As the characteristic nuclear features of papillary carcinoma have lost their status as the only and decisive criterion for malignancy due to the definition of NIFTP, a new definition of the morphological criteria of papillary carcinoma was necessary. Furthermore, this is coupled with alterations in the cytological evaluation of fine-needle biopsies (FNB) of the thyroid. With the establishment of NIFTP, the definition of thyroid tumors with extremely low malignancy potential represents a worth striving for and welcome development for avoidance of superfluous cancer diagnoses, not only for thyroid tumors.