Follicular morphological characteristics may be associated with invasion in follicular thyroid neoplasms with papillary-like nuclear features.

Research paper by Nuray N Can, Mehmet M Celik, Yavuz Atakan YA Sezer, Filiz F Ozyilmaz, Semra S Ayturk, Ebru E Tastekin, Necdet N Sut, Hakan H Gurkan, Funda F Ustun, Buket Yilmaz BY Bulbul, Sibel S Guldiken, Fulya Oz FO Puyan

Indexed on: 30 Apr '17Published on: 30 Apr '17Published in: Bosnian journal of basic medical sciences / Udruzenje basicnih mediciniskih znanosti = Association of Basic Medical Sciences


The newly proposed nomenclature and diagnostic criteria for encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC), the noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), could improve the consistency and accuracy of diagnosing this entity. Diagnosis of NIFTP requires evaluation of the complete tumor border or capsule. The presence of tumor invasion in follicular thyroid neoplasms with papillary-like nuclear features has been recently discussed by many authors. In this study, we examined the predictive value and association of follicular morphological characteristics with the tumor invasion. In addition, we analyzed the association between tumor encapsulation and molecular profile in EFVPTC/NIFTP cases. A total of 106 cases of FVPTC were included in the study. The tumors were grouped based on presence of tumor capsule and characteristics of tumor border, as 1) completely encapsulated tumors, 2) encapsulated tumors with invasion, 3) infiltrative tumors without capsule. Clinicopathological features, histomorphological features [nuclear criteria, minor diagnostic features, follicles oriented perpendicularly to tumor border/capsule (FOPBC)] and molecular alterations in BRAF, NRAS, and KRAS genes were evaluated. FOPBC were significantly more frequently seen in encapsulated tumors with invasion (p = 0.008). The nuclear features were not associated with the presence of encapsulation and characteristics of tumor border. BRAF mutation was more frequent in infiltrative tumors, while an NRAS mutation was more frequent in encapsulated tumors, but the results were not statistically significant (p = 0.917). In conclusion, FOPBC histomorphological feature may be associated with tumor invasion in EFVPTC/NIFTP. Additionally, BRAF/KRAS/NRAS mutation analysis may prevent inadequate treatment in these patients.

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