Noninvasive follicular thyroid neoplasm with papillary-like nuclear features

Abstract

Recently, it was proposed that some papillary thyroid carcinomas (PTC) will no longer be termed 'cancer' and are christened as 'noninvasive follicular thyroid neoplasm with papillary-like nuclear features' (NIFTP). As this is a recent definition, little information is available about NIFTP. The objective of this study was to report the frequency, ultrasonographic appearance, cytology result and long-term evolution of cases of NIFTP seen at our institution. We excluded tumours ≤1 cm. The sample consisted of 129 patients. Sixty-four patients were submitted to total thyroidectomy and 65 to lobectomy. These patients with NIFTP did not receive radioiodine. NIFTP corresponded to 15% of cases diagnosed as PTC >1 cm. An ultrasonographic appearance considered to be of low suspicion for malignancy was common in NIFTP (32.5%), whereas a highly suspicious appearance was uncommon (5%). NIFTP frequently exhibited indeterminate cytology (62%), while malignant cytology was uncommon (4%). The patients were followed up for 12-146 months (median 72 months) after surgery. None of the patients developed structural disease during follow-up. Comparing the concentrations of thyroglobulin (Tg) and anti-Tg antibodies (TgAb) obtained 6-12 months after surgery and in the last assessment, none of the patients exhibited an increase in these markers.

Does noninvasive follicular thyroid neoplasm with papillary‐like nuclear features have distinctive features on sonography?

“…Continued)There is only one other study that examined the sonographic features of NIFTP 6. In this study, cases of NIFTP on ultrasound were found to be of "low suspicion for malignancy" according to Haugen et al's American Thyroid Association pattern classifications 1,6. In their study NIFTP more commonly displayed wider-than-tall shape, smooth borders, solid type nodules and lack of calcifications, findings similar to our study.…”

“…In this study, cases of NIFTP on ultrasound were found to be of "low suspicion for malignancy" according to Haugen et al's American Thyroid Association pattern classifications 1,6. This study did not compare NIFTP to other benign or malignant entities, nor examine Doppler flow pattern or grade, findings that add more information to the literature as reported in our study(Table 3) 6. This study did not compare NIFTP to other benign or malignant entities, nor examine Doppler flow pattern or grade, findings that add more information to the literature as reported in our study(Table 3) 6.…”

“…Continued)There is only one other study that examined the sonographic features of NIFTP 6. In this study, cases of NIFTP on ultrasound were found to be of "low suspicion for malignancy" according to Haugen et al's American Thyroid Association pattern classifications 1,6.…”

“…6 To the best of our knowledge, this paper is the first study to evaluate sonographic features of NIFTP and contrast them with the sonographic features of PTC and FA. 6 To the best of our knowledge, this paper is the first study to evaluate sonographic features of NIFTP and contrast them with the sonographic features of PTC and FA.…”

Sonographic and cytologic differences of NIFTP from infiltrative or invasive encapsulated follicular variant of papillary thyroid carcinoma

“…Ultrasound [16][17][18] and cytologic studies [19][20][21][22][23][24] useful in the differentiation of NIFTP from PTC are summarized in Table I.…”