Clinical implications of follicular and Hurthle cell carcinoma in an iodine-sufficient area.

Abstract

The clinical importance of follicular thyroid carcinoma (FTC) and Hurthle cell carcinoma (HCC) is underestimated because of their relatively low frequency in Korea, which is an iodine-sufficient area [1,2]. In addition, the limited clini-cal experience and the small number of available investigational studies have made it problematic to form appropriate recommendations regarding manage-ment plans, such as the optimal surgical intervention and follow-up strategies, based on thorough clinical evidence re-garding the prognostic factors and nat-ural history o f these diseases.In this multicenter study, the authors performed analyses assessing the clini-copathological features and long-term outcomes of FTC and HCC patients over 6 years [3]. They compared the ini -tial tumor aggressiveness and dis-ease-free survival of FTC and HCC, and analyzed the prognostic factors for each histological subtype. Together with the currently available clinical evidence, this study might provide useful infor-mation and novel insights into Korean patients with FTC and HCC.FTC does not show the obvious nu-clear changes that are characteristic of papillary thyroid cancer (PTC) [4]. The architectural distortion and oncocytic characteristics observed in FTC are also found in benign Hurthle cell neo -plasms [5]. Therefore, the preoperative differential diagnosis of FTC and HCC from benign adenoma using ul-trasonography features and fine nee-dle aspiration (FNA) biopsy is often challenging. These histopathological characteristics of FTC and HCC were clearly visible in the results of FNA analyses in this multicenter study. Of the FTC and HCC subjects in this study, 45% and 33% showed a nonma-lignant cytopathology, respectively. This suggests the possible necessity for novel diagnostic markers to clearly discriminate between FTC and HCC preoperatively.In general, patients with HCC have a poorer prognosis than those with FTC [6]. Consistent with previous reports, this multicenter study also showed that patients with HCC were older and had more lymphovascular invasion than those with FTC. However, no prognostic markers to predict the ini-tial clinicopathological features or disease-free survival for HCC were identified. The authors analyzed the combined data of 563 patients from four different major hospitals; most patients were diagnosed with FTC, and only 80 were diagnosed with HCC. Unfortunately, this discrepancy in the number of study subjects between the two groups might limit the validity of any comparisons of tumor behavior