Noninvasive Follicular Neoplasm of Thyroid With Papillary Like Nuclear Features: A Redefined Indolent Neoplasm of the Thyroid Gland

Follicular variant of papillary thyroid carcinoma (FVPC) represents approximately 30% of all papillary thyroid carcinomas and includes encapsulated, both invasive and noninvasive forms (E-FVPC), and infiltrative FVPCs with different biological behaviors and molecular profiles. The E-FVPC exhibits very low regional recurrence and metastatic potential with a biological behavior similar to that of follicular adenomas. In 2015, a panel of endocrine pathologists, endocrinologists, surgeons, and patient advocates recommended the revision of the diagnostic terminology for cases of noninvasive E-FVPC to rename them as “noninvasive follicular thyroid neoplasm with papillary-like nuclear features.” This revised term was defined by a specific set of morphological features characterized by a noninvasive follicular patterned neoplasm with nuclear features of papillary thyroid carcinoma, scant nuclear pseudoinclusions, and lack of papillary structures and psammoma bodies. The downgrading of noninvasive follicular thyroid neoplasms with papillary-like nuclear features to “not cancer” influences not only the histologic diagnosis but also the preoperative fine-needle aspiration diagnosis and the associated malignancy risk of various diagnostic categories used in the reporting of thyroid fine-needle aspiration specimens. The case presented here with follow-up discussion highlights the pathologic features, potential controversies, and management of patients with this diagnosis.
Source: Pathology Case Reviews - Category: Pathology Tags: Case Reviews Source Type: research