Can cytology and the Thyroid Imaging, Reporting, and Data System (TI-RADS) identify noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) before surgery?

INTRODUCTION: In 2017, the American College of Radiology (ACR) created the Thyroid Imaging, Reporting, and Data System (TI-RADS) to select thyroid nodules for fine-needle aspiration (FNA). The objective of this study is to find out whether ACR TI-RADS is useful in triaging thyroid follicular cells with papillary-like nuclear features obtained by FNA to determine the extent of surgery. MATERIAL AND METHODS: The grayscale ultrasound of 76 noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), 41 encapsulated (E), and 79 infiltrative (I) follicular variant (FV) of papillary thyroid carcinoma (PTC) were reviewed and assigned TI-RADS points and then suspicion levels. RESULTS: Of the 39 tumors with high suspicion level, 32 were IFVPTC, and seven were EFVPTC. Of the 137 tumors with moderate suspicion level, 47 were IFVPTC, 34 were EFVPTC, and 56 were NIFTP. Of the 19 tumors with mild suspicion level, all were NIFTP. The only tumor with no suspicion was an NIFTP. IFVPTC had a significantly higher suspicion level than EFVPTC and NIFTP (P < 0.0001). The difference in suspicion level between EFVPTC and NIFTP is not statistically significant. None of the cases of NIFTP in the study had a high suspicion level. CONCLUSIONS: The study demonstrates that cytology interpreted in the context of ACR TI-RADS suspicion levels can separate NIFTP from many IFVPTC and a few EFVPTC with overt invasion. PTC could be diagnosed in cytology if cells with papillary-like nuclear features derived from TR5 nodules. The nodules with TR4 or less that yield similar cells require surgical pathology to diagnose FVPTC with microscopic capsular or vascular invasions.

Pathologic basis of the sonographic differences between thyroid cancer and noninvasive follicular thyroid neoplasm with papillary-like nuclear features.

Ultrasonography is pivotal in triage thyroid biopsy in the era after the identification of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). This pictorial essay illustrates the pathologic basis of the sonographic features that distinguish NIFTP from thyroid cancers. In this study, we present the correlations of ultrasonography to ×1 histopathology to assess shape and margin characteristics. Markedly hypoechoic nodules correlate to microfollicular/solid nodules, while isoechoic/hyperechoic thyroid nodules correlate to normofollicular/macrofollicular nodules. The ultrasound findings of NIFTP and minimally invasive encapsulated thyroid cancers are similar. Both are well-circumscribed, oval-to-round nodules with regular margins. Blurred or microlobulated margins indicate infiltrating tumors, while lobulated margins are characteristic of expansile tumors. Overtly invasive encapsulated tumors are characterized by oval-to-round nodules with irregular or lobulated margins. The ultrasound findings for infiltrative thyroid cancers show at least one of the following malignant features: marked hypoechoicity, taller-than-wide shape, microcalcifications, and blurred or microlobulated margins.

Sonographic and cytologic differences of NIFTP from infiltrative or invasive encapsulated follicular variant of papillary thyroid carcinoma: A Review of 179 Cases.

We reclassified 179 cases of the follicular variant (FV) of papillary thyroid carcinoma (PTC) into 72 (40.2%) noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), 37 (20.7%) encapsulated FVPTC with invasion (EFVPTC), and 70 (39.1%) infiltrative FVPTC (IFVPTC) without a capsule. In the NIFTP group, 5.6% cytology were hypercellular and the remainder low to moderate cellularity. PTC nuclei were absent in 18%, focally present in 37.5%, and diffusely present in 44.4%. In the EFVPTC group, 8.1% cytology were hypercellular and the reminder low to moderate cellularity. PTC nuclei were absent in 24.3%, focally present in 29.7% and diffusely present in 45.9%. In IFVPTC group, 24.3% cytology were hypercellular and the reminder low to moderate cellularity. PTC nuclei were diffusely present in 88.6% and focally present in 11.4%. The ultrasound findings for NIFTP and minimally invasive EFVPTC typically demonstrated a circumscribed oval/round nodule with a hypoechoic rim, and the Doppler was mostly hypervascular. The ultrasound findings for overtly invasive EFVPTC typically showed a round/oval nodule with irregular margins and the Doppler was mostly hypervascular. The ultrasound findings for IFVPTC group showed at least one of the malignant gray-scale features: markedly hypoechoic, taller-than-wide, microcalcifications or blurred margins. The Doppler in this group was mostly avascular. An algorithm is proposed to triage thyroid FNA based on different scenarios of the sampled cells, interpreted in the context of ultrasound features with histology outcomes. Five composite ultrasound-cytology-histology figures illustrate NIFTP, IFVPTC, and IFVPTC with intratumoral fibrosis, microfollicular EFVPTC and normofollicular EFVPTC. Diagn. Cytopathol. 2017;45:533-541. © 2017 Wiley Periodicals, Inc.

Most Thyroid Cancers Detected by Sonography Lack Intranodular Vascularity on Color Doppler Imaging: Review of the Literature and Sonographic-Pathologic Correlations for 698 Thyroid Neoplasms.

OBJECTIVES: This study investigated the controversy of whether hypervascularity on color Doppler sonography correlates with thyroid malignancy by reviewing the literature and sonographic-pathologic correlation. METHODS: Over a 20-year period, 698 thyroid nodules had color Doppler and histopathologic data. Intranodular vascularity was graded 0 to 3+, and histopathologic findings were recorded. RESULTS: The data were collected from 698 patients (557 women and 141 men) with a mean age of 48 years (range, 16-87 years). Of the 698 neoplasms, 425 were malignant (mean size, 1.7 cm; range, 0.4-9 cm; 150 ≤1 cm), and 273 were benign. The carcinomas included 391 papillary, 12 Hürthle cell, 9 medullary, 6 follicular, 5 poorly differentiated, and 2 anaplastic. The grading of intranodular vascularity was 0 in 63.3%, 1+ in 12.9%, 2+ in 6.6%, and 3+ in 17.4%. Among thyroid carcinomas, follicular carcinoma and the encapsulated subtype of the follicular variant of papillary carcinoma had significantly higher intranodular vascularity than the rest (P < .0001). Benign neoplasms included 226 follicular adenoma/adenomatoid nodules (mean size, 3.2 cm; range, 1.2-8.0 cm), 42 Hürthle cell adenoma/adenomatoid nodules (mean size, 2.6 cm; range, 0.8-5.5 cm), and 5 hyalinizing trabecular adenomas (mean size, 2.4 cm; range, 0.6-6.0 cm; 4 ≤1 cm). The grading of intranodular vascularity was 0 in 6.9%, 1+ in 12.1%, 2+ in 2.6%, and 3+ in 78.4%. Intranodular hypervascularity was associated with adenoma/adenomatoid thyroid nodules, whereas a lack of vascularity was related to thyroid carcinomas (P < .0001). CONCLUSIONS: Most sonographically detected thyroid cancers lack intranodular vascularity, and most hypervascular thyroid nodules are adenoma/adenomatoid nodules, the encapsulated subtype of the follicular variant of papillary carcinoma, or follicular carcinomas.