Diffuse sclerosing variant of papillary carcinoma of the thyroid: A 35-year comparative study at a single institution

Background: Diffuse sclerosing variant (DSV) is a rare variant of papillary thyroid carcinoma (PTC), and the features of this carcinoma have not been fully characterized. The aim of this study was to analyze the clinicopathologic features of a large cohort of patients with this disease. Methods: We reclassified primary thyroid carcinomas treated in a 35-year study period and studied the clinicopathologic features and outcomes of DSV of PTC in comparison with classic PTC. Results: Fifteen patients (2 men and 13 women) with DSV of PTC were identified who had surgical resection of the thyroid. Fine-needle aspiration biopsy diagnosed 83% (10 of 12) of the tumors. Compared with classic PTC, patients with DSV presented at a younger age (mean age, 29 vs. 46 years; P = .0001), had larger tumors (mean diameter, 3.6 vs. 2.2 cm; P = .002), and had a higher incidence of cervical nodal metastases (80% vs. 43%; P = .006). Ten patients had received postoperative iodine 131 ablation, and four had also received external-beam irradiation. Distant metastases were detected in two patients (one in lung and one in brain). One third (5 of 15) of the patients developed disease recurrence. Lymph node recurrence was detected in one patient 12 years after the initial operation. Over a median follow-up period of 10.7 years, one patient with an initial incomplete excision died of the carcinoma. The overall disease-specific survival rate was 93%. Conclusions: DSV of PTC had distinctive clinicopathologic features and a high incidence of recurrence after operation but had a prognosis similar to that of classic PTC.