Multifocal Versus Solitary Papillary Thyroid Carcinoma

Background Papillary Thyroid Carcinoma (PTC) which accounts for >85 % of all thyroid cancers in iodine-rich areas, appears either as a single tumor or as two or more, neoplastic foci within the thyroid gland (Multifocal PTC). We present the comparative results between solitary and MFC PTC. Materials and methods Demographics, tumor characteristics (size, laterality, foci number, histologic subtype) and TNM staging were compared between solitary and MFPTC patients. The presence of lymphocytic or Hashimoto's thyroditis was also recorded. Results From January 2008 to December 2012, among 647 PTC patients, 241(37.2 %) had MFPTC 177 females (73.4 %) and 64 males (26.6 %), mean age 48.5 years (range 12-87). Mean number of tumor foci was 3.3 (range 2-26). MFPTC patients presented with more advanced T stage (28.2 vs. 18.7 %, p = 0.01) and more LN metastases (28.6 vs. 15.5 %, p < 0.001). Foci number correlates with male gender and LN metastases (p = 0.014 and p = 0.019, respectively). Central (N1a) or lateral (N1b) LN involvement correlates strongly with male gender (p = 0.024) and younger age (p < 0.001). The follicular variant was the next most frequent histologic subtype associated with extremely rare LN metastases. Conclusion MFPTC comprises a more aggressive form of papillary thyroid cancer since it is associated with more frequent N1a/N1b disease and occurs more frequently in T3/T4 patients. MFPTC foci number correlates with male gender and LN metastases.