[Hashimoto's disease with thyroid cancer: report of six cases].

Hashimoto's disease associated with thyroid cancer is not common. From January 1976 to December 1994, a total of 95 patients with Hashimoto's disease were treated surgically. Six (5 Papillary 1 folicular) of 95 patients had thyroid cancer which was concomitantly revealed pathologically. They were all women with mean age of 30.3 years. The size of tumor was 0.3-2.0 cm. Follow-up for 1-17 years showed that they were all alive and healthy. Two patients were misdiagnosed as having anaplastic carcinoma but the definitive diagnosis by immunohistochemical analysis was thyroid malignant lymphoma (B-cell type). Hashimoto's disease and thyroid cancer relationship, diagnosis, and treatment are discussed.