[Immunohistochemical identification of biochemical defect of dyshormonogenetic goiter]

This is a report of two cases of congenital goiter in which it was possible to indicate, through immunohistochemistry method, the disorder in the hormonal synthesis. One of these cases was of a sixteen-year-old woman, with goiter since childhood who used thyroid hormone replacement for ten years. Pathology showed coloid goiter with follicular adenoma. Immunohistochemistry showed strong mainly apical follicular cell thyroglobulin. Thyroglobulin was not found in the coloid. This finding is compatible with a malfunction of thyroglobulin exocitosis. The reaction for thyroid peroxidase was adequate for the age. The other case was a 13 year-old-boy with goiter and thyroid hormone replacement since the age of 1 year. He presented slight mental and growth retardation. Pathology showed coloid goiter with follicular adenoma. Immunohistochemistry study showed a very weak and diffuse reaction for thyroid peroxidase while the reaction for thyroglobulin was adequate. These findings indicate quantitative defect of thyroid peroxidase.