46,XX male disorder of sexual development.

An individual's sexual phenotype is usually determined by the presence or absence of the Y chromosome in the embryo's karyotype, however, due to abnormal X/Y terminal exchange through male meiosis, a few individuals develop male genitalia in the absence of the Y chromosome. This case report presents an adolescent referred to the Pediatric Endocrinology Unit due to bilateral gynecomastia. A diagnosis of hypergonadotropic hypogonadism was established and chromosomal analysis disclosed 46,XX karyotype, with the gene locus found on one of his X chromosomes. A multidisciplinary approach, including psychological support and genetic counseling, is ideal for the management of these patients. Neoplastic transformation of the dysgenetic gonads has been described in several cases, and hence self-examinations and regular ultrasounds are commonly advised.