Tamoxifen Treatment of Progressive Precocious Puberty in a Patient with McCune-Albright Syndrome

Treatment of progressive precocious puberty in patients with McCune-Albright syndrome (MAS) has traditionally been with aromatase inhibitors, such as testolactone. However, the use of these agents has been characterized by problems with both efficacy and compliance. We report a case of MAS in which tamoxifen proved to be a successful alternative in the treatment of progressive precocious puberty. An African-American female presented with MAS at 2-5/12 years. Frequent menses, skeletal maturation and growth acceleration prompted initiation of therapy with testolactone at 22 mg/kg/d. Over the next 13 months, the patient's puberty advanced unchecked, despite progressive increases in the dose of testolactone. At age 4 years, medication was discontinued due to treatment failure. At 4-6/12 years, bone age was 10 years, predicted adult height was 137 cm, and monthly bleeding continued. Tamoxifen was then begun on an experimental basis. In response, the patient experienced immediate cessation of menses, and had an abrupt decrease in the rates of pubertal progression and linear growth. This patient has now been maintained on tamoxifen for over three years with no apparent adverse effects. GnRH analogue therapy was begun when the onset of central precocious puberty was noted. Predicted adult height has improved to 154 cm and growth velocity and skeletal maturation remain stable. Our results suggest that tamoxifen may have a valuable role in the treatment of precocious puberty in patients with MAS and may lead to superior results compared with those achieved with aromatase inhibitors.