A sixty-one-year-old female was admitted to our hospital in October 1988 because of fever and a right neck mass associated with redness and tenderness. The size of the thyroid mass had gradually increased over 3 months. Two masses were detected in the thyroid by ultrasonography and MRI. She has positive thyroid autoantibodies, high CRP levels and high erythrocyte sedimentation rates. While she had normal white blood cell counts, massive neutrophils were obtained from her thyroid mass by aspiration biopsy, indicating acute suppurative thyroiditis. However, we could not find any bacteria to cause suppurative thyroiditis either in the blood or in thyroid aspirates. Serum levels of thyroid hormone were slightly elevated but she did not complain of any thyrotoxic symptoms. Radioactive iodine uptake (RAIU) of the thyroid gland was markedly decreased (2%/24h). Following treatment with antibiotics, her inflammation and symptoms immediately improved, and pus spontaneously ran from the collapsed thyroid mass. Then serum thyroid hormone levels and RAIU were normalized and the right thyroid mass disappeared. She was discharged in December 1988. There were no signs of recurrence of suppurative thyroiditis until now. She received a pharyngo-esophageal barium examination in search of the route of infection 4 times, but no fistula was revealed. However, as her left thyroid mass consistently remained thereafter, an operation of the left thyroid mass was performed in December 1989. The histologic examination of the resected thyroid revealed the coexistence of encapsulated follicular adenoma, minute papillary carcinoma and chronic thyroiditis. There are few reports of such a case having a combination of suppurative thyroiditis, thyroid cancer and chronic thyroiditis observed in an elderly female.