Endocrine Abstracts

A three year old boy was referred for surgical correction of an undescended right testis. Intra-operatively he was found to have a hyperplastic right gonad which was in continuation with a unilateral fallopian tube, prompting analysis of his karyotype. This showed 46XX/XY mosaicism with 88% of the cells being XX and 12% XY. The post-operative histology confirmed mixed testicular and ovarian tissue in the right gonad. He appeared phenotypically male and had blaschko lines consistent with the diagnosis of genetic mosaicism. Although a HCG stimulation test showed some testicular function in his left gonad, this was insufficient to allow normal progression through puberty. He commenced regular Sustanon injections aged 12 years with good effect. Over the next few years, his left testicular volume gradually increased to 8–10 mls, after which there was no further enlargement raising the possibility of a dysgenetic testis. Ultrasound imaging showed a single small left testis with slight heterogeneity but no malignant features. At the completion of puberty, he reported no symptoms suggestive of erectile dysfunction, had a muscular physique and was referred for a right testicular implant. Sustanon was discontinued and since then his serum AFP, HCG and testosterone levels have remained within the normal ranges. He is currently 25 years old and married. On clinical examination, the left gonad remains soft, in keeping with a degree of germ cell failure, but there are no palpable worrying features. Recent semen analysis shows persistent severe oligospermia. He remains off testosterone replacement (serum testosterone level 18 nmol/l) with the aim to freeze his sperm, as soon as the levels are sufficient to allow this, for potential intracytoplasmic sperm injection, should he wish to pursue this. This case describes a rare cause of hypogonadism. It emphasises the role and treatment aims of testosterone replacement in young hypogonadal males, the impact this can have on spermatogenesis and the complex fertility issues that may arise in adulthood.