Study of various nuclear features of papillary thyroid carcinoma in other thyroid lesions

Introduction: Papillary thyroid carcinoma is the only thyroid malignancy that is diagnosed on the basis of its nuclear characteristics, regardless of cytoplasmic features, growth patterns or immunohistochemistry. Although nuclear features have become hallmark for the diagnosis, they are neither constant nor specific. They can be seen in other tumours and non-tumours condition of thyroid. With the aim to know the frequency of various nuclear features of papillary thyroid carcinoma in other thyroid lesions and also to find out which of the various nuclear features are most diagnostic of papillary thyroid carcinoma, this study was done. Materials and Methods: The present study was conducted on Fine needle aspiration cytology of thyroid lesions where corresponding histopathological diagnosis was available, from 2010 to 2016. All cytology smears of were reviewed by two investigators who were blinded with respect to the final histopathological diagnosis. Results: 155 cases were included in the study; category 2 was the most common constituting 76%, followed by category 6 which was 35%. Frequency of various nuclear features of papillary carcinoma in other thyroid categories varied from 10% to 33%. Conclusion: Frequency of various nuclear features of papillary carcinoma in other thyroid categories varied from 10% to 33% and Intranuclear cytoplasmic inclusions are the most diagnostic nuclear features of papillary carcinoma.