Patients with disorders of sex development (DSDs), previously known as intersex disorders, have abnormal gonadal development and an increased risk of germ cell tumors. 45X/46,XY mosaicism is a disorder of sex development characterized by the presence of two distinct cell lines with differing sex chromosomes. Individuals with this chromosomal anomaly have an elevated risk of developing germ cell tumors Pre-malignant lesions include intra-tubular germ cell neoplasia and gonadoblastomas (GBs).

This case involves a 12-year-old raised as female, who presented with ambiguous genitalia, perceived by the parents as a clitoral mass. Karyotyping revealed a mosaic pattern consisting of 43 analyzed cells, with a combination of 45X and 46,XY cell lines, indicating a mosaic monosomy X alongside a normal male cell line. Imaging with lower abdominal Magnetic resonance imaging confirmed the presence of an infantile uterus, and a solid nodular structure in the right adnexal region most likely a gonad and an indeterminate adenexal structure on the left. The patient underwent clitoroplasty, laparoscopic bilateral gonadectomy and salphingectomy. Histopathological analysis revealed that the right gonad contained foci of gonadoblastoma, while the left gonad was identified as a streak gonad.

 

45X/46,XY mosaicism is a disorder of sexual development. Patients with mosaicism have a higher risk of developing germ cell tumors including gonadoblastoma. Gonadoblastoma is a clinically benign mixed germ cell-stromal tumor with a significant predisposition to progress into malignant neoplasms. When the risk of malignancy is compared with the potential gonadal function, hormone production and future fertility, prophylactic gonadectomy may be indicated due to the increased risk of gonadal tumors.