| Autor: |
Paniza ACJ; Division of Genetics, Department of Morphology and Genetics, Genetic Bases of Thyroid Tumors Laboratory, Universidade Federal de São Paulo, São Paulo, Brazil., Mendes TB; Division of Genetics, Department of Morphology and Genetics, Genetic Bases of Thyroid Tumors Laboratory, Universidade Federal de São Paulo, São Paulo, Brazil., Viana MDB; Division of Genetics, Department of Morphology and Genetics, Genetic Bases of Thyroid Tumors Laboratory, Universidade Federal de São Paulo, São Paulo, Brazil., Thomaz DMD; Division of Genetics, Department of Morphology and Genetics, Genetic Bases of Thyroid Tumors Laboratory, Universidade Federal de São Paulo, São Paulo, Brazil., Chiappini PBO; Department of Pathology, Hospital Heliópolis, São Paulo, Brazil., Colozza-Gama GA; Division of Genetics, Department of Morphology and Genetics, Genetic Bases of Thyroid Tumors Laboratory, Universidade Federal de São Paulo, São Paulo, Brazil., Lindsey SC; Division of Endocrinology, Department of Medicine, Laboratory of Molecular and Translational Endocrinology, Universidade Federal de São Paulo, São Paulo, Brazil., de Carvalho MB; Department of Head and Neck Surgery and Otorhinolaryngology, Hospital Heliópolis, São Paulo, Brazil., Alves VAF; Department of Pathology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil., Curioni O; Department of Head and Neck Surgery and Otorhinolaryngology, Hospital Heliópolis, São Paulo, Brazil., Bastos AU; Division of Genetics, Department of Morphology and Genetics, Genetic Bases of Thyroid Tumors Laboratory, Universidade Federal de São Paulo, São Paulo, Brazil.; Department of Microbiology, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil., Cerutti JM; Division of Genetics, Department of Morphology and Genetics, Genetic Bases of Thyroid Tumors Laboratory, Universidade Federal de São Paulo, São Paulo, Brazil. |
| Abstrakt: |
The recent reclassification of a follicular variant of papillary thyroid carcinoma (FVPTC), subset as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), aims to avoid overtreatment of patients with an indolent lesion. The diagnosis of NIFTP has recently been revisited using more rigid criteria. This study presents histological and molecular findings and a long clinical follow-up of 94 FVPTC, 40 cases of follicular adenoma (FTA) and 22 cases of follicular carcinoma (FTC) that were classified before the advent of the NIFTP reclassification. All slides were reviewed using these rigid criteria and analysis of numerous sections of paraffin blocks and reclassified as 7 NIFTPs, 2 EFVPTCs, 29 infiltrative FVPTC (IFVPTCs), 57 invasive EFVPTC (I-EFVPTCs), 39 FTAs and 22 FTCs. Remarkably, EFVPTC and NIFTP patients were all free of disease at the end of follow-up and showed no BRAF mutation. Only one NIFTP sample harbored mutations, an NRAS Q61R. PAX8/PPARG fusion was found in I-EFVPTCs and FTC. Although additional studies are needed to identify a specific molecular profile to aid in the diagnosis of lesions with borderline morphological characteristics, we confirmed that the BRAF V600E mutation is an important tool to exclude the diagnosis of NIFTP. We also show that rigorous histopathological criteria should be strongly followed to avoid missing lesions in which more aggressive behavior is present, mainly via the analysis of capsule or vascular invasion and the presence of papillary structures. |
