Combined "Mixed Medullary-Follicular" and "Papillary" Carcinoma of the Thyroid with Lymph Node Metastasis.

We report a case of combined "mixed medullary follicular" and "papIlary" carcinoma of the thyroid that occurred in a 44 yr-old Japanese woman. The grossly single 3 cm tumor was histologically composed of both mixed medullary follicular carcinoma and papillary carcinoma, which abutted against each other with a clear border between two components. Immunohistochemically, the component of medullary carcinoma was positive for calcitonin and carcinoembryonic antigen (CEA), and the follicular carcinoma and papillary carcinoma components were positive for thyroglobulin. Lymph node metastasis was also noted. The patient has been alive without recurrence for 20 yr. To the best of our knowledge, this is the first reported case in the literature. We report this unique case of thyroid carcinoma and review related thyroid malignancies.