Clinicopathological parameters for predicting non-invasive follicular thyroid neoplasm with papillary features (NIFTP)

Is it Possible to Diagnose "Non-Invasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features" Preoperatively?

There is no accepted consensus or algorithm for the preoperative diagnosis of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) in patients with thyroid nodules. In this study, we evaluated the importance of preoperative neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in the differential diagnosis of NIFTP. Pathology preparations of 209 patients with a follicular variant of papillary thyroid carcinoma (FVPTC) diagnosed after thyroid surgery in a tertiary health center between January 2010 and January 2020 were re-evaluated. Patients were divided into NIFTP and encapsulated follicular variant papillary thyroid carcinoma (EFVPTC) to compare. Of the patients, 58 (27.7%) were NIFTP, and 151 (72.3%) were EFVPTC. There was no statistically significant difference in terms of age (p = 0.46), tumor size (p = 0.51), gender (p = 0.48), and surgical technique (p = 0.78) between the groups. The probability of the neutrophil-to-lymphocyte ratio (NLR) > 2 is more common in the EFVPTC group. It was statistically significant that the NIFTP group was 1.96 times more likely to have NLR > 2 (OR: 1.96, 95% CI: 1.06-3.63) (p < 0.05). However, there was no risk difference between the groups in terms of the platelet-to-lymphocyte ratio (PLR) (OR: 0.76, 95% CI: 0.41-1.43) (p > 0.05). The diagnosis of NIFTP should be kept in mind in the evaluation of patients whose thyroid fine-needle aspiration (FNA) biopsy results are in the intermediate group. NIFTP exhibits better prognostic findings than classic thyroid papillary cancer and EFVPTC. Therefore, preoperative diagnosis of NIFTP in line with laboratory, ultrasonography, and FNA findings will save the patient from unnecessary overtreatment.

What you see might not be what you get: Analysis of 15 prospective cases of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)

Introduction

Noninvasive follicular thyroid neoplasm with papillary-like nuclear (NIFTP) is a new entity. No previous study reported prospective cases, outlining using many quantitative and qualitative variables.

Methods

Retrospective analysis of all (15) prospective NIFTP cases diagnosed between 2017 and 2021 at our institution. Statistical quantitative analysis outlined demographic, history, ultrasound, histopathology and treatment characteristics. Qualitative analysis examined the cases, with details provided on three cases to highlight the different possible presentations and configurations.

Results

Mean age was 41.5 ± 9.91 years, 73.3% were females, and mean BMI was 29.49 ± 5.74 kg/m². About 87% patients were symptomatic; 86.6% had neck swelling. Ultrasound (US) showed multiple nodules in 71.4% of cases. Fine-needle aspiration cytology (FNAC) showed that follicular lesion of undetermined significance (42.8%) was most common, followed by benign nodule (21.3%). Using the Bethesda System for Reporting Thyroid Cytopathology, 7 cases were category III, 3 category IV, 3 category II, and 1 category I. 60% of patients underwent total thyroidectomy. All cases were diagnosed postoperatively, 2 patients had additional papillary microcarcinoma. In 3 cases, the NIFTP site in the histopathology of resected specimen was different than the US-recommended site of the FNAC.

Conclusion

We found discrepancies in the site and diagnosis of the preoperative US recommendation for the FNAC vs the postoperative histopathology of the specimen. These suggest that NIFTP might be incidentally and postoperatively diagnosed, irrespective of US or FNAC findings, hence its ‘true’ incidence might remain underestimated. As NIFTP cases higher BMI, Future research could predict preoperative diagnosis of NIFTP and explore associations with BMI.

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Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is follicular type of papillary carcinoma

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NIFTP is postoperative diagnosis. Correlation of clinical, imaging, cytological and post-operative histopathology is needed

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Site and diagnosis of suspected NIFTP on US-guided FNAC and histopathology after resection requires more research

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Preoperative diagnosis of NIFTP requires more studies. Until guidelines are available, regular follow up should be done