ESPE Abstracts

McCune-Albright syndrome consists of pigmented skin patches, polyostotic fibrous dysplasia, and a variety of endocrine disorders. Café au lait spots are characteristic skin lesions that reflect the onset of the somatic mutations in melanocytes during embryonic development. Polyostotic fibrous dysplasia is caused by activation of the parathyroid hormone receptor pathway in bone. Hormonal hypersecretion is the result of constitutive cyclic AMP production caused by inactivation of the GTPase activity of G_sa. The G_sa mutations occur postzygotically, leading to a mosaic pattern of mutant expression. McCune-Albright syndrome affects males and females in equal numbers.The disorder is estimated to affect 1 in 100,000 to 1 in 1,000,000 individuals in the general population. Because the disorder is difficult to diagnose, affected individuals may go undiagnosed or misdiagnosed, making it difficult to determine the true frequency of MAS in the general population. Previously MAS was determined as a condition that had three clinical features, such as café au lait spots, fibrous dysplasia, and hyperfunction of an endocrine gland. Recently McCune Albright syndrome consists of at least two of the following above.

We report two cases with MAS to emphasize that all patients with pigmented skin patches should be evaluated to exclude other manifestations of MAS. Our cases supports the statement that only two of clinical characteristics mentioned above, are sufficient to be present to consider MAS.