LAUSR

INTRODUCTION Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is a newly defined entity and accepted as a tumor precursor. OBJECTIVES We aimed to examine the features of the subjects diagnosed with follicular variant papillary thyroid carcinoma (FVPTC), which are classified as NIFPT in the recent classification. This study compares clinical, radiological, histopathological, and molecular features of NIFTP and FVPTC. PATIENTS AND METHODS 247 patients with FVPTC were retrospectively examined and pathology specimens were reviewed.  Results: Subjects were divided into 2 groups (NIFTP group: 107 patients; FVPTC group: 140 patients). There was a significant difference in terms of the percentage of pathologic nodules with irregular borders detected in preoperative neck ultrasonography (NIFTP group: 6.5%, FVPTC group: 15.7%, P = 0.02). Central lymph node dissection specimens of 50 patients in NIFTP group showed normal findings, while 4 of 70 patients (5.7%) in FVPTC group were found to have lymph node metastasis (P = 0.14). In addition, multivariable analysis (binary logistic regression) showed that follicular variant papillary thyroid cancer was positively associated only with irregular border and extrathyroidal extension (P = 0.02, P <0.001, respectively). CONCLUSIONS We suggest that patients diagnosed with NIFTP according to new classification may be considered as low-risk patients and margin characteristics of nodule detected in preoperative ultrasonography may be helpful in differential diagnosis.