The Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma is not an Aggressive Subtype of Papillary Carcinoma

Abstract

Background: The diffuse sclerosing variant of papillary thyroid carcinoma (DSV) is a rare subtype of papillary thyroid carcinoma (PTC), and the prognosis of patients with this variant is not yet fully understood. The aim of this study was to determine whether DSV is a poorer prognostic factor than non-DSV. Methods: We reviewed the histologic slides of 12,664 primary PTC cases and divided them into DSV and non- DSV groups. Based on the results of the follow-up study and the age distribution of patients, we selected the data from 810 female patients and compared outcomes between patients with DSV and patients with non-DSV. Results: Of all initial patients, 43 had DSV. Of these, 4 patients were deceased, and 39 were alive with a mean survival of 11.1 ± 9.7 years (mean ± SD) after surgery; the deceased patients were all female patients with papillary non-microcarcinoma (PNMC, >10 mm diameter). A substudy of female PNMC patients by age showed that a cutoff at age 33 years was optimal for analyzing the DSV and non-DSV groups. Of 810 female patients younger than 33 years with PNMC, 25 had DSV and 785 had non-DSV. Of the patients with non-DSV, 23 patients died, including 5 deaths from PTC. The overall mortality and disease-specific mortality rates of the selected patients were not statistically significant between the DSV and non-DSV groups (2/25 vs. 23/785, p=0.18 and 1/24 vs. 5/767, p=0.17, respectively). Conclusion: DSV is not an aggressive subtype of PTC and patients with DSV do not require more aggressive therapy than patients with non-DSV of the same stage.