ABSTRACT
Objective: The objective of this study is to retrospectively evaluate follicular variant of papillary thyroid carcinoma (FVPTC) and reclassify encapsulated FVPTC as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) according to the criteria proposed by The Endocrine Pathology Society working group in 2015 to correlate with outcome. Materials and Methods: Retrospective review of case records of all patients diagnosed as carcinoma of thyroid between 2015 and 2016 was done for the histologic subtype. Gross and microscopic features on resected specimens of FVPTC were reviewed and subtyped as invasive and encapsulated based on capsular/vascular invasion; the encapsulated forms were further studied for size, number, follicular architecture, nuclear features, presence of psammoma bodies, stromal fibrosis, necrosis, mitoses, and lymph node status. Results: Out of the 383 patients with thyroid carcinomas in the study period, 349 were PTC which included 106 FVPTC. Thirty-three patients fulfilled the criteria to be labeled as NIFTP. Total thyroidectomy was performed in 8 patients and hemithyroidectomy in 25 patients. Lymph node dissection along with total thyroidectomy was done in 3 and completion thyroidectomy following hemithyroidectomy was done in 9. There were 29 single and 4 multiple lesions with size varying from 0.2 to 7 cm including 5 lesions measuring <1 cm. The involvement was confined to one lobe in 31 and both lobes in 2 specimens. Patients are on follow-up with no recurrence till date. Conclusion: Thyroid carcinomas currently diagnosed as FVPTC should be evaluated for criteria of NIFTP to avoid overtreatment as they have an indolent behavior.
ABSTRACT
BACKGROUND: This study was performed to analyze cytologic diagnosis of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) and its impact on the risk of malignancy (ROM) in the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). METHODS: Five thousand five hundred and forty-nine cases of thyroid fine-needle aspiration cytology (FNAC) diagnosed between 2012 and 2014 were included in this study. Diagnostic categories based on TBSRTC were compared with final surgical diagnoses, and the ROM in each category was calculated both when NIFTP was included in malignant lesions and when excluded from malignant lesions. RESULTS: Of the 5,549 thyroid FNAC cases, 1,891 cases underwent surgical resection. In final diagnosis, 1,700 cases were revealed as papillary thyroid carcinoma (PTC), and 25 cases were reclassified as NIFTP. The cytologic diagnoses of NIFTP were non-diagnostic in one, benign in five, atypia of undetermined significance (AUS) in 14, follicular neoplasm in two, and suspicious for malignancy in three cases. Collectively, NIFTP/encapsulated follicular variant of PTC (EFVPTC) were more frequently classified as benign, AUS, or follicular neoplasm and less frequently categorized as malignant compared to conventional PTCs. Exclusion of NIFTP from malignant diagnoses resulted in a slight decrease in malignancy rates in non-diagnostic, benign, AUS, follicular neoplasm, and suspicious for malignancy categories without any statistical significance. CONCLUSIONS: The decrease in the ROM was not significant when NIFTP was excluded from malignant lesions. In thyroid FNACs, NIFTP/EFVPTCs were mostly classified into indeterminate categories. Therefore, it might be feasible to separate NIFTP/EFVPTC from conventional PTC on FNAC to guide clinicians to conservative management for patients with NIFTP/EFVPTC.
Subject(s)
Humans , Biopsy, Fine-Needle , Diagnosis , Thyroid Gland , Thyroid NeoplasmsABSTRACT
Objective To analyze of the prevalence of encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) and noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) by 2017 World Health Organization ( WHO) classification of tumors of endocrine organs in Guiyang. Methods A retrospectively analysis of patients who had a thyroid surgery and confirmed thyroid cancer by pathological diagnosis in the Affiliated Hospital of Guizhou Medical University from 2009 to 2016. PTC and FVPTC by 2014 WHO classification of tumors of endocrine organs , and according to the 2017 WHO classification of tumors of endocrine organs ,the thyroid papillary carcinomas were reviewed and some had been confirmed as EFVPTC and NIFTP, with analysis of the prevalence and prognosis of NIFTP. Results Of the 1207 cases of thyroid carcinoma, 1150 cases were papillary carcinoma, the constituent ratio of thyroid carcinoma was 95.28％, the FVPTC was 72 cases, and the proportion of thyroid carcinoma was 5. 97％; the proportion of FVPTC in thyroid carcinoma decreased from 2009 to 2016 ( P <0.05). After pathological sections being reviewed, 10 cases had been confirmed as non-encapsulated infiltrative FVPTC, the ratio of thyroid cancer to thyroid cancer was 0.83％; EFVPTC was found in 62 cases, accounting for 5.14％ of thyroid carcinoma, these included 2 cases of NIFTP confirmed by the 2017 WHO classification of tumors of endocrine organs and 60 cases encapsulated invasive FVPTC, the percentage of thyroid carcinoma was 0.17％ and 4.97％. 62 cases of EFVPTC with the exception of 11 cases without further visit, while the remaining 51 cases of EFVPTC were followed up. Death, local or distant metastases were defined as adverse events. An adverse event was seen in 11 of 49 of the cases of invasive EFVPTC, including 2 died of disease; The NIFTP were alive with no evidence of disease. Conclusion The diagnosis of NIFTP according to new WHO classification of endocrine organ tumors in 2017 has little expected impact in Guiyang.