Pure papillary thyroid carcinoma (PPTC) and the follicular variant of papillary thyroid carcinoma (FVPTC) are the most common subtypes of papillary thyroid carcinoma (PTC). The aim of this study was to investigate if there are any differences in clinicopathological features of these two subgroups.

We performed a retrospective chart review of patients who were treated for PPTC and FVPTC between September 2003 and April 2008. Four hundred fifty patients were shown to have PPTC (91.8%) and forty (8.2%) had FVPTC after a histologic review. The two groups were compared in terms of the clinicopathologic features and the results of preoperative ultrasonography (USG), the fine needle aspiration cytology (FNAC), the frozen section biopsy and the surgical treatment

The tumor size was significantly larger in the FVPTC group than in the PPTC group (1.47 cm versus 1.08 cm, respectively P=0.024). However, both groups had similar clinicopathologic features in terms of age, gender, capsular invasion, multifocality, lymph node metastasis, the MACIS score and the TNM stage. Further, the operative method did not differ between the two groups. The sensitivities of USG and frozen section biopsy for diagnosing FVPTC were significantly lower than those for PPTC (53.85% versus 72.95%, respectively, P=0.045, 81.58% versus 97.25%, respectively, P=0.049).

The FVPTC group presented with a larger tumor size, and the clinicopathologic features of the FVPTC group did not significantly differ from those of the PPTC group. Although further studies with longer follow-up are required, these results suggest that the patients in both groups should be treated identically.