Suspicious for follicular neoplasm or follicular neoplasm? The dilemma of a pathologist and a surgeon.

Abstract

Cytological material obtained from Fine Needle Aspiration Biopsy (FNAB) does not permit us to distinguish between follicular carcinomas, adenomas, and hyperplastic nodules. The limitations of the method are: lack of possibility to assess the presence of tumour capsule, eventual capsular invasion, and angioinvasion. An unequivocal conclusion of whether what we have to deal with is a neoplastic or benign lesion is possible only after histopathological examination. The aim of the study was to confirm justification for using the term "Suspicious for Follicular Neoplasm" (SFN) in cytological diagnostics of thyroid carcinoma. Three hundred and fifty-two primary SFN FNAB diagnoses (diagnostic category IV [DC IV] - according to Bethesda System) obtained from 2010 to 2015 in the Institute of Oncology in Gliwice were analysed, and their correlation with histopathological diagnoses was verified. In the Institute of Oncology in Gliwice, 352 primary SFN diagnoses (diagnostic category IV [DC IV] - according to Bethesda System) were established. Surgical treatment was undertaken after first FNAB in six cases, giving confirmation of a neoplasm in five cases, one of which was a follicular carcinoma. Second FNAB performed in 90 patients confirmed DC IV diagnosis in 53 cases. Third FNAB concerned 26 patients, providing another 14 diagnoses of DC IV. 26 out of 352 patients were subjected to surgery, and then histopathological examination confirmed a neoplasm in 19 cases (which comprises 73%), five of which were carcinomas. High positive predictive value PPV = 73% of SFN diagnosis justifies undertaking surgical treatment in any case of this diagnosis.