Thyroid cancer with coexistent Hashimoto's thyroiditis. Clinical assessment and management.

Hashimoto's thyroiditis is a common thyroid disorder. Because of the difficulty of diagnosing a coexisting thyroid cancer, its management remains controversial. We reviewed 120 cases of thyroid cancer seen in our institution during an 11-year period (1976 through 1986) and defined the clinical characteristics of patients with both entities. Thirteen patients had concomitant cancer and Hashimoto's thyroiditis. Six of the 13 patients had a history of thyroiditis before the diagnosis of thyroid cancer. The remaining seven patients had evidence of Hashimoto's thyroiditis on histologic review of the thyroid specimen. The two most common characteristics prompting surgical intervention were the presence of a nonsuppressing dominant nodule and a cold area on thyroid scan. Twelve patients underwent preoperative fine-needle aspiration cytologic examination, but only in three were the results considered to be indicative of cancer. All 13 patients remained disease free. Despite the apparent indolence of thyroid cancer associated with Hashimoto's thyroiditis, selective surgical treatment of patients with clinical thyroiditis is indicated.