RESUMEN
PURPOSE:Differential diagnosis of sexual precocity has been aided by new imaging techniques and endocrine evaluation. Sexual precocity, defined as the appearance of secondary sexual characteristics before the age of 8 years in girls and 9 years in boys, was studied to evaluate the sex incidence and etiology of sexual precocity. METHODS:A total 95 children(87 girls and 8 boys) who were diagnosed with sexual precocity at St. Mary's Hospital, Catholic University Medical College from 1984 to 1996, were studied. All underwent standard anthropometric measures. They were assinged to diagnostic categories on the basis of clinical assessment, endocrine evaluation, radiologic imaging, and pelvic ultrasonography. RESULTS: 1) The most common cause of sexual precocity was premature thelarche, 50 cases(52.6%) of all children. 2) Central precocious puberty was noted in 7 girls and 3 boys(female to male ratio 2.3:1). The causes were not identified in 6 cases(85.7%) in girls, but the causes were not found in 1 cases(33.3%) in boys. The idiopathic central precocious puberty occurs at least two fold more frequently in girls than in boys. 3) Incomplete precocious puberty was noted in 29 girls and 5 boys(female to male ratio 5.8:1). In the causes of 29 girls with incomplete precocious puberty, congenital adrenal hyperplasia were found in 23 cases, autonomous functional ovarian cyst in 5 cases and McCune-Albright syndrome in 1 case. In the causes of 5 boys with incomplete precocious puberty, virilizing adrenal cortical tumor were found in 3 cases, congenital adrenal hyperplasia in 1 case, and hepatoblastoma in 1 case. CONCLUSION: Sexual precocity occurs at least ten fold more frequently in girls than in boys. Premature thelarche is the most common form of sexual precocity.