Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma: A 17-year Experience at a Single Institution

ABSTRACT

PURPOSE: The diffuse sclerosing variant of papillary thyroid carcinoma (DSPTC) is a rare histological subtype characterized by unique morphological features and aggressive behavior. The aim of this study was to evaluate the clinocopathologic features and outcome of DSPTC over 17 years. METHODS: Twenty-six cases of DSPTC (0.5%) were identified among 5,527 patients with papillary thyroid carcinoma treated between July 1990 and June 2007 at the Department of Surgery, Yonsei University College of Medicine. The clinicopathological features and outcome of these patients with DSPTC were evaluated. The median follow-up period was 46 months (range, 1~202 months). RESULTS: Twenty patients were females and 6 were males, the age ranged from 5 to 70 years (median 30.5 years). Histologically, most of the patients demonstrated diffuse involvement of one or both lobes of the thyroid, variable degree of lymphocytic infiltration, squamous metaplasia, psammoma bodies, extensive sclerosis and extracapsular extension, along with a high incidence of lateral neck node metastases (17/26, 65.4%). Treatment was by complete surgical resection by means of a total thyroidectomy (24/26, 92.3%), modified radical neck dissection (17/26, 65.4%) and postoperative radioactive iodine therapy (22/26, 84.6%). Recurrences were noted in 6 cases (5 locoregional recurrence and 1 distant metastasis in bone). One patient died of an unrelated disease. The 10-year overall survival and disease specific survival rates were 83.8% and 100%, retrospectively, but disease free survival was 48.0%. CONCLUSION: DSPTC showed an unfavorable clinical course with a low overall disease free survival. An aggressive therapeutic approach and close follow-up are recommended.