Journal of Research in Medical Sciences1735-199515420100525Granulosa cell tumor in a six-year-old girl presented as precocious puberty240242ENMahinHashemipourMohammad HassanMoaddabPediatric Endocrinologist, Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. moadab@med.mui.ac.irMasoudNazemParvinMahzouniMehdiSalek200909272010022220100124Ovarian sex cord-stromal tumors, including granulose cell tumors (GCTs), are a group of neoplasms that occur rarely, especially in children. Only 0.1 percent of all ovarian tumors and 4-5 percent of GCTs occur in children. The most common presentation of these tumors in children is precocious puberty. We report a 6 years old girl with isosexual precocity, presented as premature thelarche and vaginal bleeding. Ultrasonography of pelvis showed a ypoechoic solid mass of left ovary.Microscopic features of the resected mass were characteristic of juvenile GCT. Although in most of girls with precocious puberty, the etiology is idiopathic, important causes, such as ovarian tumors must be considered.KEYWORDS: Granulosa Cell Tumor, Puberty, Children.