Central nodal metastases in papillary thyroid carcinoma based on tumor histologic type and focality.

OBJECTIVE To determine the risk of nodal metastases to the central compartment from differentiated papillary thyroid carcinoma (PTC) relative to known prognostic variables. DESIGN A 7-year single-institutional retrospective review. SETTING Tertiary academic center. PATIENTS A total of 115 patients undergoing central neck dissection (CND) for PTC or follicular variant PTC (FVPTC). MAIN OUTCOME MEASURE Number, location, and positivity of lymph nodes for malignant disease in the central compartment based on patient age, sex, extrathyroidal extension, and primary tumor size, histologic type, and focality. RESULTS Eighty-seven percent of patients had PTC, and 13% had FVPTC. Bilateral (64%) or ipsilateral (36%) CND was performed in patients with PTC. Patients with FVPTC underwent only ipsilateral CND. There was no significant difference in the number of lymph nodes retrieved based on patient age or sex, histologic type of the primary tumor, size or focality, or surgeon or pathologist. Seventy-eight percent of patients with PTC had malignant lymph nodes in the ipsilateral (75%) or bilateral/contralateral (69%) central compartment. Ipsilateral nodal metastases directly correlated with tumor multifocality (r = 0.93; P = .001) and size (r = 0.89; P = .001). Bilateral nodal metastases directly correlated with tumor multifocality (r = 0.92; P = .001) but was independent of size (r = 0.56; P = .001). No malignant lymph nodes were identified in the central compartment of FVPTC. CONCLUSIONS Malignant central nodal metastases occur with high frequency in PTC but not in FVPTC. The risk of metastases correlated with the size and multifocality of the primary tumor. Additional studies are warranted to determine the extent of CND in patients with and without known multifocal disease and to determine the role of CND in patients with FVPTC.