Hyperthyroidism related to McCune-Albright syndrome: Report of two cases and review of the literature.

Introduction: McCune-Albright syndrome is a sporadic disease clinicaly characterized by polyostotic fibrous dysplasia, "cafe-au-lait" cutaneous spots and hyperfunctional endocrinopathies, such as precocious puberty, hyperthyroidism, acromegaly and others. The biologic physiopathology of the disease is based on an activating mutation of the gene for the Gs protein which mediates the activation of adenyl cyclase and subsequent gland autonomous secretion. The thyroid gland is usually involved in this disease, being hyperthyroidism the second most common endocrinopathy seen after precocious puberty. Objective: Revision of the literature since 1937 to 1997, adding our casuistic and discussing the adequate treatment for the hyperthyroidism in the syndrome. Results: Among 85 cases identified with the syndrome, hyperthyroidism treatment was described in 26 of them. Fifteen were submitted to surgery (total thyroidectomy), 6 were submitted to iodotherapy and 5 were treated with antithyroid drugs (ATD-propylthiouracil, carbimazole or methimazole). In some cases, treatment association was done. Conclusion: McCune-Albright syndrome is a rare disease, combining polyostotic fibrous dysplasia, "cafe-au-lait" cutaneous spots and hyperfunctional endocrinopathies. Cases with hyperthyroidism are treated iniatially clinically, but definitive ablation with, surgery or radioiodine treatment is the most indicated option.