Diagnostic significance of various cytomorphological features and their quantification for the diagnosis of papillary carcinoma thyroid on fine needle aspiration cytology

Abstract

Introduction: The relative reliability of the morphological features for making a diagnosis of PTC when considered independently is debatable. Quantification of morphological features has been attempted to improve the diagnostic efficacy of FNA thyroid, but universal acceptance is lacking. Aim: This study was aimed to analyze the independent diagnostic significance of the four common morphological features-Nuclear grooves (NG), Intra-nuclear cytoplasmic inclusions (INCI), Papillary Fragments and Metaplastic Cytoplasm, in thyroid swellings using a quantitative approach. Materials and Methods: Retrospective study including thyroid FNA cases with corresponding histopathological report was analyzed. Eighty six cases had at least one of the four morphological features mentioned. The cases with NG were categorized into three groups: >/= 20%; 10-19% and Results: The sensitivity, specificity, PPV and NPV of NG for PTC in the category of ? 20% was 53.3%, 98.2%, 94.1% and 79.7% respectively and the same in the category of > 10% were 66.7%, 75%, 58.8% and 80.8% respectively. Specificity and sensitivity of ‘Frequent’ INCI were 100% and 36.67% respectively. Conclusion: Typical morphological features of PTC can be seen in non-malignant conditions as well. Occurrence of NG >20% and INCI >5% are highly specific for the diagnosis of PTC. Cases with NG between 10-19% should be considered as ‘suspicious for malignancy’ and pathologist should cautiously look for other morphological features. Keywords: Papillary carcinoma thyroid (PTC), FNAC, Cytology, Morphology, Quantification.