Ultrasonographic and Cytological Diagnostic Difficulties of Follicular-Variant Papillary Thyroid Carcinoma

Objective: The Nuclear properties of both follicular-variant papillary thyroid carcinoma and conventional variant of papillary thyroid carcinoma are the same, but some diagnostic difficulties exist with the follicular variant. In the present study, we aimed to define the reasons for this diagnostic difficulty and raise awareness of this problem once more. Materials and Methods: In our study, we retrospectively reviewed the ultrasonographic findings and fine-needle aspiration biopsies of 104 patients whose histopathology had been surgically proven as being either the conventional or follicular-variant papillary thyroid carcinoma in a hospital between January 2012 and December 2018. Results: A highly suspicious sonographic pattern occurred in 56% of the conventional type, whereas only 21% of the follicular variant resulted in a suspicious sonographic pattern. The fine-needle aspiration biopsy of the conventional papillary carcinoma was consistent with malignancy or was suspected of malignancy in 80% of the cases, whereas this percentage was 58% for the follicular variant. Conclusion: Thus, the follicular-variant of papillary thyroid carcinoma has a higher correlation to benign sonographic features and a higher rate of false negative results via cytological examination in comparison to the conventional variant. Radiologists, pathologists, and clinicians must be aware of this situation and demonstrate care in the evaluation of nodules that appear benign.