Klinefelter Mosaicism 46, XX/47, XXY with Ovotestis- DSD

Klinefelter syndrome is a relatively common chromosomal condition affecting approximately 1 in 500-1,000 males. 46, XX /47 XXY Klinefelter Syndrome mosaicism is rare enough, resulting in a few cases described in literature. Variable phenotypes and clinical presentations such as gynecomastia, infertility, cryptorchidism, and disorders of sexual development (DSD) are associated with this karyotype presentation. The association of Klinefelter syndrome mosaicism 46 XX/47 XXY and OT DSD is a rare feature. We report the case of a 34-year-old man who presented for semen analysis and karyotyping in our unit. The patient had bilateral gynecomastia and absence of facial hair. Penile length was 4,5 cm with an external meatus located on the posterior face of the phallus, characterizing a posterior hypospadias. Testis was palpable in the right hemiscrotum, but the left hemiscrotum was empty. Ultrasonography revealed the presence of the left gonad located in the left iliac fossa, while the right gonad in the scrotum had testicular morphology according to ultrasound exam. Chromosomal analysis revealed 46, XX/47, XXY mosaicism, and semen analysis an azoospermia. Our patient underwent surgery because of the risk of malignancy, and histopathologic examination of the left excised gonad confirmed the structure to be an ovotestis. The biopsy of the right gonad, realized for eventual cryopreservation, revealed atrophic seminiferous tubules and a pseudo tumoral aspect of Leydig cells with hyperplasia without atypia. Personalized approach and multidisciplinary care are needed to get a diagnosis, resolve sex reassignment, and improve the quality of life of the patient. In that feature, the percentage of XX cells could play a role on phenotype, particularly on Müllerrian structure persistence, but also on a relative increased risk of malignancy degenerescence compared to other cases of OT-DSD.