The Bethesda System for Reporting Thyroid Cytopathology is applicable to frozen section diagnosis in children

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) offers standardized and widely understood diagnostic categories for reporting thyroid cytology diagnoses. We compared the utility of TBSRTC categories in pediatric cytology diagnoses and pediatric intraoperative frozen section diagnoses. We examined the experience of our primary and referral care center over a 20-year period. This included 182 thyroidectomy patients who underwent 64 preoperative fine-needle aspirations and 91 intraoperative frozen section evaluations, including 38 patients evaluated sequentially by each method. All diagnoses were retrospectively reclassified into TBSRTC categories and correlated with the final thyroidectomy diagnoses. For each sampling method, malignant final diagnoses were observed at similar frequencies to rates predicted by TBSRTC. Malignant final diagnoses following fine-needle aspiration or frozen section diagnoses in TBSRTC categories other than malignant or suspicious for malignancy most often resulted from difficulty in detecting papillary carcinoma, including difficulty detecting the nuclear characteristics of papillary carcinoma in frozen sections. The limitations of needle biopsy and frozen section evaluations differ, yet serial utilization of these procedures was rarely informative. Based on the experience of our institution, classification of cytology and frozen section diagnosis by TBSRTC predicts a risk of malignancy similar to the guidance offered by TBSRTC. We recommend including a TBSRTC category when reporting either thyroid cytology or frozen section diagnoses in children.