Somatostatin-immunoreactive cells in medullary carcinoma of the thyroid

Ten medullary carcinomas of the thyroid were examined by immunohistochemistry using antisera against calcitonin, somatostatin, and ACTH. In addition to calcitonin cells, eight of the tumors contained somatostatin-immunoreactive cells in varying numbers. No ACTH-immunoreactive cells were found. The results indicate that thyroid medullary carcinomas often are multihormonal, and that somatostatin is common in such tumors. In contrast to calcitonin cells, somatostatin cells are not found in normal human thyroid tissue.