Risk of malignancy in different diagnostic categories of The Bethesda System of Reporting Thyroid Cytopathology differ in Indian population: A tertiary care center experience.

  • BACKGROUND: The Bethesda system of reporting thyroid cytopathology (TBSRTC) in now a widely used and most robust thyroid cytology classification scheme with pre determined implied malignancy risk in each diagnostic category. Cancers are known to show racial, geographic and genetic variability. Prior knowledge of malignancy risk helps surgeons and clinicians plan the patient management in a better way. This study was undertaken to evaluate the diagnostic utility of Bethesda system of reporting thyroid cytopathology with analysis of risk of neoplasia (RON) and risk of malignancy (ROM) in each diagnostic category in Indian patients with thyroid nodule.  

    METHOD: A retrospective cohort study, including patients with palpable thyroid swelling who underwent fine needle aspiration. Histological specimens were also reviewed when available.

    RESULTS: Of these 517 aspirates 4.4% smears were non-diagnostic. The majority of the lesions (68.8%) fall under benign category. Histopathological correlation was available in 230 cases. The ROM for non diagnostic, benign, atypia of undetermined significance/ follicular lesion of undetermined significance (AUS/FLUS), follicular neoplasm/ suspicious for follicular neoplasm (FN/SFN), suspicious for malignancy and malignant categories were 36.4%, 1.12%, 27.3%, 37.5%, 100% and 100% respectively. The RON in these categories was 54.5%, 1.96%, 36.4%, 78.1%, 100 % and 100% respectively.

    CONCLUSION: Fine needle aspiration is sensitive and specific method in diagnosing thyroid swelling with a high sensitivity and specificity for malignant lesions. The risk of malignancy in majority of Bethesda’s diagnostic categories were significantly different and higher than that mentioned in old as well as recent updated TBSRTC, in Indian population.

 

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