An analysis of trends of incidence and cytohistological correlation of papillary carcinoma of the thyroid gland with evaluation of discordant cases.

BACKGROUND: The role of fine-needle aspiration cytology (FNAC) in thyroid nodules has been well-studied but there is a paucity of studies solely involving papillary thyroid carcinoma (PTC). The diagnostic criteria for PTC are established but still there is a worrisome possibility of false positive and false-negative results, which can have a serious impact on patient care. This article correlates the cytological and histological diagnosis of PTC with an eventual aim of analyzing the cause of false positive and false negative results in order to prevent misdiagnosis. An increase in the incidence of PTC in the younger population has been noted.

AIMS: To analyze the epidemiological trends and cytohistological correlation of PTC and evaluate the discordant cases and pitfalls of FNAC.

MATERIALS AND METHODS: Seventy-two cases who had undergone both FNAC and histopathological examination (HPE) of the thyroid gland were selected. Age and sex distribution as well as cytohistological correlation were done for all the cases.

RESULTS: Cytohistological correlation was 81.94%. False positives were 5.56% and the false negative rate was 13.2%. Sensitivity was 86.7% and the positive predictive value was 93.6%. The peak age was 31-40 years among females and 41-60 years among males. Seven of our patients were <20 years of age (10%).

CONCLUSION: FNAC is an indispensible tool for the early diagnosis of PTC. However, certain conditions of the thyroid gland can cause diagnostic dilemma. Awareness of pathologists regarding these pitfalls can prevent misdiagnosis and provide better patient care. Increasing the incidence of PTC with a more striking increase in the younger population makes early diagnosis all the more important owing to better prognosis in this age group.