Histopathological Diagnostic Criteria for Non-invasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features Highlighted by Six Illustrative Cases

Open access

Abstract

Introduction. The encapsulated, non-invasive subtype of follicular variant of papillary thyroid carcinoma (FVPTC) represents approximately 10% to 20% of all thyroid cancers. Many studies over the past decade have shown that these tumors carry an indolent clinical course, with no recurrence, even in patients treated by lobectomy. Their reclassification as neoplasms with “very low malignant potential” has recently been suggested by an international group of experts and a new terminology was proposed: “non-invasive follicular thyroid neoplasm with papillary-like nuclear features” (NIFTP). However, a diagnosis of NIFTP is still challenging for many pathologists in daily practice. Presentation of case series. By presenting six illustrative cases of NIFTP, this article aims to highlight the diagnostic criteria and the burden difficulties when dealing with NIFTP cases. Characteristic histological features, inclusion and exclusion criteria for NIFTP, as well as sampling guidelines and differential diagnosis challenges are all discussed. Conclusions. The diagnosis of NIFTP is not straightforward and requires meeting strict inclusion and exclusion criteria. Total sampling of the tumor capsule in these cases is mandatory in order to exclude invasion (capsular and/or vascular). A diagnosis of NIFTP promotes a less-aggressive patient management that is, no need for completion thyroidectomy or radioactive iodine therapy.

1. Davies L, Welch HG - Current thyroid cancer trends in the United States. JAMA Otolaryngol Head Neck Surg. 2014;140(4):317-322.

2. Liu J, Singh B, Tallini G et al. - Follicular variant of papillary thyroid carcinoma: a clinicopathologic study of a problematic entity. Cancer. 2006;107:1255-1264.

3. Howitt BE, Jia Y, Sholl LM, Barletta JA - Molecular alterations in partiallyencapsulated or well-circumscribed follicular variant of papillary thyroid carcinoma. Thyroid. 2013;23(10):1256-1262.

4. Rivera M, Tuttle RM, Patel S, Shaha A, Shah JP, Ghossein RA - Encapsulated papillary thyroid carcinoma: a clinico-pathologic study of 106 cases with emphasis on its morphologic subtypes (histologic growth pattern). Thyroid. 2009;19(2):119-127.

5. Rivera M, Ricarte-Filho J, Knauf J et al. - Molecular genotyping of papillary thyroid carcinoma follicular variant according to its histological subtypes (encapsulated vs infiltrative) reveals distinct BRAF and RAS mutation patterns. Mod Pathol. 2010;23(9):1191-1200.

6. Vivero M, Kraft S, Barletta JA - Risk stratification of follicular variant of papillary thyroid carcinoma. Thyroid. 2013;23(3):273-279.

7. Ganly I, Wang L, Tuttle RM et al. - Invasion rather than nuclear features correlates with outcome in encapsulated follicular tumors: further evidence for the reclassification of the encapsulated papillary thyroid carcinoma follicular variant. Hum Pathol. 2015;46(5):657-664.

8. Burningham AR, Krishnan J, Davidson BJ, Ringel MD, Burman KD - Papillary and follicular variant of papillary carcinoma of the thyroid: Initial presentation and response to therapy. Otolaryngol Head Neck Surg. 2005;132(6):840-844.

9. Rosario PW, Penna GC, Calsolari MR - Noninvasive encapsulated follicular variant of papillary thyroid carcinoma: is lobectomy sufficient for tumours >/=1 cm? Clin Endocrinol (Oxf). 2014;81(4):630-632.

10. Thompson LD - Ninety-four cases of encapsulated follicular variant of papillary thyroid carcinoma: A name change to Noninvasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features would help prevent overtreatment. Mod Pathol. 2016;29(7):698-707.

11. Nikiforov YE, Seethala RR, Tallini G et al. - Nomenclature Revision for Encapsulated Follicular Variant of Papillary Thyroid Carcinoma: A Paradigm Shift to Reduce Overtreatment of Indolent Tumors. JAMA Oncol. 2016;2(8):1023-1029.

12. Nikiforov Y, Randolph G, Ghossein R, Tallini G, Kakudo K, Thompson LDR, LiVolsi V, Tuttle RM, Papotti M - Non-invasive follicular thyroid neoplasm with papillary-like nuclear features, in Lloyd RV, Osamura RY, Klopper JP, Rosai J (eds): WHO classification of tumors of endocrine organs. International Agency for Research on Cancer. Lyon, 2017, pg 78-80.

13. Lloyd RV, Asa SL, LiVolsi VA et al. - The evolving diagnosis of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Hum Pathol. 2018;74:1-4.

14. Jung CK, Little MP, Lubin JH et al. - The increase in thyroid cancer incidence during the last four decades is accompanied by a high frequency of BRAF mutations and a sharp increase in RAS mutations. J Clin Endocrinol Metab. 2014;99(2):E276-E285.

15. Hung YP, Barletta JA - A user’s guide to non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Histopathology. 2018;72:53-69.

16. Kakudo K, El-Naggar AK, Hodak SP et al. - Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) in thyroid tumor classification. Pathol Int. 2018; 68(6):327-333.

17. Seethala RR, Baloch ZW, Barletta JA et al. - Noninvasive follicular thyroid neoplasm with papillary-like nuclear features: a review for pathologists. Mod Pathol. 2018;31:39-55.

Acta Medica Marisiensis

The Journal of The University of Medicine and Pharmacy of Targu-Mures

Journal Information

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 24 24 22
PDF Downloads 17 17 14