ESPE Abstracts

Introduction: McCune-Albright syndrome (MAS) is characterized by fibrous dysplasia (FD), cafe-au-lait skin spots and precocious puberty (PP). MAS is a rare disorder and its prevalence is estimated to be between 1/100 000 and 1/1 000 000. Activating somatic mutations of GNAS gene located on chromosome 20q13 encoding the α-subunit of the regulatory Gsα protein are responsible for the entity.

Observation: This is a patient referred by her attending physician at the age of 6 years and 5 months for treatment of precocious puberty. She is 1m22 tall and weighs 23 kg. The patient has already presented a puberty episode at 5 years of life, characterized by pink leucorrhoea. She then presents a breast enlargement of status S2. Developed and pigmented lips, and type P2 pubic hair. The biology shows an increased E2 at 75 pg/ml with indosable gonadotropins. Pelvic ultrasound shows a stimulated uterus with polycystic ovaries. She also has a unique and irregular café-au-lait skin spot on the right flank. Bone age is overmature by 1 year. The thyroid balance is normal as well as the androgens. treatment with an aromatase inhibitor has been initiated.

Discussion: Diagnosis of is usually clinical. The evaluation of patients with MAS must be guided by knowledge of all the possible impairments and by appropriate examinations. Genetic testing is possible, but not routinely available.

Conclusion: MAS is a rare disease. Genetic counseling should be offered although MAS is not hereditary. Malignant transformation of FD lesions is rare and occurs in, probably, less than 1% of case.