Carcinoma papilífero da tireoide associado à tireoidite de Hashimoto: frequência e aspectos histopatológicos

Abstract

INTRODUCTION: Papillary carcinoma is the most common type of thyroid cancer and Hashimoto's thyroiditis is the most frequent cause of hypothyroidism in areas where iodine levels are adequate. Several investigators have detected an increased incidence of papillary thyroid carcinoma in patients with Hashimoto's thyroiditis. In histopathological diagnosis routine, there is an apparent association between these two pathologies. OBJECTIVE: To determine the association between Hashimoto's thyroiditis and papillary thyroid carcinoma, evaluating the histopathological aspects, when concomitantly present or isolated. METHODS: A retrospective study was carried out with data from the archives of the Pathology Service at hospital Barao de Lucena, SUS (Recife-PE, Brazil), which included 95 cases amongst 472 thyroid surgeries performed from January 1995 through January 2005. RESULTS: There were 35 cases (7.4%) of Hashimoto's thyroiditis, 48 cases (10.2%) of papillary carcinoma and 12 cases (2.5%) of significant association of these pathologies (p < 0.05), which corresponded to 20% of the papillary carcinoma cases. There was no significant difference as to age, gender, presence of concomitant benign neoplasia, larger tumor diameter, multifocality or histological variant of papillary carcinoma, between cases of isolated papillary carcinoma or carcinoma associated with Hashimoto's thyroiditis. There was a significant association concerning the higher frequency of a tumor capsule in isolated papillary carcinomas when compared with papillary carcinomas with concomitant Hashimoto's thyroiditis. CONCLUSION: The presence of Hashimoto's thyroiditis should alert to the risk of papillary thyroid carcinoma development, as these diseases were significantly associated.