[Human chorionic gonadotropin-secreting gonadoblastomas in a girl of 45, X Turner syndrome: a case report and literature review].

To summarize the experience in diagnosis and treatment of 45, X Turner syndrome (TS) with gonadal Y chromosome mosaicism and bilateral gonadoblastoma (Gb) secreting human chorionic gonadotrophin(HCG). A female patient aged 5 years and 3 months was admitted to the hospital with a complaint of "enlarged breasts for 27 months, and elevated blood β-HCG for 8 months". The clinical data were summarized, and related literature up to March 2022 with the key words"Turner syndrome" "Gonadoblastoma" "Y chromosome" "human chorionic gonadotropin" "precocious" in PubMed, CNKI and Wanfang databases were reviewed. The girl went to the local hospital for 2-month breast development at age of 3 years, and was found with a heart murmur diagnosed with "pulmonary venous malformation and atrial septal defect (secondary foramen type)". Surgical correction was performed. She experienced the progressive breast development, rapid linear growth and markedly advanced skeletal age, which cannot be explained by partial activation in the hypothalamic-pituitary-gonadal axis determined at the age of 3 years and 7 months in local hospital. Then whole-exome sequencing revealed chromosome number abnormality 45, X, which was confirmed by Karyotyping. At the age of 4 years and 6 months, serum β-HCG was found to be elevated (24.9 U/L) with no lesion found at the local hospital. On physical examination, she was found with breast development, pubic hair development and clitoromegaly with elevated serum testosterone (1.96 μg/L) and β-HCG (32.3 U/L). Sex determining region Y(SRY) gene was negative in peripheral blood sample. Thoracic and abdominal CT, head and pelvic magnetic resonance imaging were normal. Exploratory laparotomy confirmed the presence of a left adnexal tumor and a right fibrous streak gonad. During surgery, simultaneous samples of bilateral gonadal and peripheral venous blood were obtained and serum β-HCG, estradiol and testosteron concentrations was higher to lower from left gonadal venous blood, right gonadal venous blood, to peripheral venous blood. Bilateral gonadectomy was performed. Histopathology revealed bilateral gonadoblastomas. SRY was positive in bilateral gonadal tissues. After surgery, serum E, testerone and β-HCG returned to normal. So far 4 cases of HCG-secreting gonadoblastoma had been reported worldwide. The phenotypes of the 4 cases were all female, with virilization or amenorrhea, and the preoperative peripheral blood β-HCG concentrations were 74.4, 5.0, 40 456.0, and 42.4 U/L, respectively. There is a high risk of Gb in TS with Y chromosome components. Gb is infrequently presented with breast development, and Gb associated with HCG secretion is rare. Karyotyping should be performed in a phenotypic female with masculinization, and virilization in TS indicates the presence of Y chromosome material with concurrent androgen secreting tumors.