Abstract
The relationship between Hashimoto's thyroiditis and thyroid carcinoma remains controversial and the coexistence is reported with varying frequency. Between 1987-1991 among 45 Hashimoto's thyroiditis only 4 (8.8%) patients were found to have concomitant thyroid carcinoma at Ankara Numune Hospital. The histologic findings of 129 thyroid carcinoma cases were reviewed further. Hashimoto thyroiditis was associated with 4 (3.1%) of all cases of thyroid carcinoma while lympositic infiltration was present in 17 (13.1%) of them. Patients coexisting carcinoma and Hashimoto's thyroiditis all had papillary carcinomas. None of the cases revealed a transitional zone which could denote carcinoma arising from proliferating epithelium between Hashimoto process and neoplastic tissue.