Study of variants of papillary carcinoma of Thyroid with a special emphasis on NIFTP (Non-invasive Follicular Thyroid Neoplasm with Papillary like nuclear features)

Rapid advances have taken place in the classification of papillary thyroid neoplasms with reclassification and addition of new variants. One such change is the addition of a new entity called NIFTP (Non-invasive Follicular Thyroid Neoplasm with Papillary like nuclear features). So called recognising its non-malignant potential. The present study is a retrospective observational cohort study on thyroidectomy specimens collected between Jan 2018 to June 2021 focussing on variants of papillary carcinoma with special emphasis on recognising NIFTP – which has got good prognosis and is considered non-malignant. Out of the 40 cases of papillary neoplasms 36 were PTC and 4 were NIFTP. Among the PTC cases 27 were classic PTC, 4 were FVPTC (Follicular Variant of Papillary Thyroid Carcinoma) 3 were papillary microcarcinoma, 1 was Warthin like Variant of PTC and 1 was Encapsulated PTC. The Study concludes that special vigilance is required in strictly adhering to the criteria proposed by new 2017 WHO classification of Papillary tumours. Recognising NIFTP as it is a non-malignant entity should be given due importance.

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HBME1 and CK19 in Non-Invasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features (NIFTP) vs Other Follicular Patterned Thyroid Lesions.

10.21203/rs.3.rs-268209/v1 ◽

2021 ◽

Author(s):

Qandeel Sadiq ◽

Radhika Sekhri ◽

Daniel Dibaba ◽

Qi Zhao ◽

Shweta Agarwal

Keyword(s):

Papillary Thyroid Carcinoma ◽

Thyroid Carcinoma ◽

Follicular Adenoma ◽

Thyroid Neoplasms ◽

University Hospital ◽

Thyroid Neoplasm ◽

Papillary Thyroid ◽

Non Invasive ◽

Significant Difference ◽

Nuclear Features

Abstract Background: Thyroid neoplasms with follicular architecture can have overlapping morphologic features and pose diagnostic confusion amongst pathologists. Various immunohistochemical stains have been investigated as potential diagnostic markers for PTC; amongst which HBME1 and CK19 have gained popularity. Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) poses similar diagnostic challenges with interobserver variability and is often misdiagnosed as adenomatoid nodule or follicular adenoma. This study aims to evaluate expression of HBME1 and CK19 in NIFTPs in comparison to other well differentiated thyroid neoplasms and benign mimickers. Method: 73 thyroid cases diagnosed over a period of 3 years at Methodist University Hospital, Memphis, TN were included in this study: 9 NIFTP, 18 papillary thyroid carcinoma (PTC), 11 follicular variant of papillary thyroid carcinoma, invasive (I-FVPTC), 24 follicular adenomas (FA), and 11 multinodular goiters/ adenomatoid nodules (MNG). A tissue microarray (TMA) was constructed and HBME1 and CK19 IHC was performed.Results: HBME1 was expressed in 77.8% NIFTPs, 88.9% PTC, 81.8% I-FVPTC, 16.7 % FA, and 18.2% MNGs. CK19 expression was seen in 66.7% NIFTPs, 83.3% PTC, 81.8% I-FVPTC, 33.3% FA and 45.4% MNGs. Difference in expression of HBME1 and CK19 was statistically significant for NIFTP vs FA (qualitative; p<0.05) and NIFTP vs MNG (p<0.05). No statistically significant difference was found for HBME1 in NIFTP vs PTC (conventional and FVPTC), p>/= 0.2. Sensitivity of HBME1 and CK19 for NIFTP were 78% and 67%, ~88% each for PTC, and 89% and 100% for FVPTC respectively, while specificity of HBME1 and CK19 for NIFTP were 53% each, ~62% each for PTC and ~55% each for FVPTC. Conclusion: Our study indicated that HBME1 and CK19 are valuable markers in differentiating NIFTPs from morphologic mimics like follicular adenoma and adenomatoid nodules/ multinodular goiter. While HBME1 and CK19 are both sensitive in diagnosing lesions with PTC like nuclear features, CK19 stains a higher number of benign lesions in comparison to HBME1. No increase in sensitivity or specificity in diagnosis of NIFTP, PTC or FVPTC was noted on combining the two antibodies.

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HBME1 and CK19 expression in non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) vs other follicular patterned thyroid lesions

World Journal of Surgical Oncology ◽

10.1186/s12957-021-02258-7 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Qandeel Sadiq ◽

Radhika Sekhri ◽

Daniel T. Dibaba ◽

Qi Zhao ◽

Shweta Agarwal

Keyword(s):

Papillary Thyroid Carcinoma ◽

Thyroid Carcinoma ◽

Follicular Adenoma ◽

Thyroid Neoplasms ◽

University Hospital ◽

Thyroid Neoplasm ◽

Papillary Thyroid ◽

Non Invasive ◽

Significant Difference ◽

Nuclear Features

Abstract Background Thyroid neoplasms with follicular architecture can have overlapping morphologic features and pose diagnostic confusion among pathologists. Various immunohistochemical stains have been investigated as potential diagnostic markers for PTC, among which HBME1 and CK19 have gained popularity. Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) poses similar diagnostic challenges with interobserver variability and is often misdiagnosed as adenomatoid nodule or follicular adenoma. This study aims to evaluate expression of HBME1 and CK19 in NIFTPs in comparison to other well-differentiated thyroid neoplasms and benign mimickers. Method Seventy-three thyroid cases diagnosed over a period of 3 years at Methodist University Hospital, Memphis, TN, USA, were included in this study: 9 NIFTP; 18 papillary thyroid carcinoma (PTC); 11 follicular variant of papillary thyroid carcinoma, invasive (I-FVPTC); 24 follicular adenomas (FA); and 11 multinodular goiters/adenomatoid nodules (MNG). A tissue microarray (TMA) was constructed and HBME1 and CK19 immunohistochemistry was performed. Results 77.8% of NIFTPs, 88.9% of PTCs, 81.8% of I-FVPTCs, 16.7% of FAs, and 18.2% of MNGs showed HBME-1 expression. 66.7% of NIFTPs, 83.3% of PTCs, 81.8% of I-FVPTCs, 33.3% of FAs, and 45.4% of MNGs expressed CK19. Difference in expression of HBME1 and CK19 was statistically significant for NIFTP vs FA (qualitative; p < 0.05) and NIFTP vs MNG (p < 0.05). No statistically significant difference was found for HBME1 in NIFTP vs PTC (conventional and FVPTC), p ≥ 0.2. Sensitivity of HBME1 and CK19 for NIFTP were 78% and 67%, ~ 88% each for PTC, and 89% and 100% for FVPTC, respectively, while specificity of HBME1 and CK19 for NIFTP were 53% each, ~ 62% each for PTC, and ~55% each for FVPTC. Conclusion Our study indicated that HBME1 and CK19 are valuable markers in differentiating NIFTPs from morphologic mimics like follicular adenoma and adenomatoid nodules/multinodular goiter. While HBME1 and CK19 are both sensitive in diagnosing lesions with PTC-like nuclear features, CK19 stains a higher number of benign lesions in comparison to HBME1. No increase in sensitivity or specificity in diagnosis of NIFTP, PTC, or FVPTC was noted on combining the two antibodies.

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