This case report represents one of the fews present in the scientific literature dealing with sex cord-stromal tumours. They are rare in the paediatric population and their incidence represents less than 5% of the testicular tumours in children and adolescents, and as a consequence little is known in the scientific community about them and how should be treated. In the following case report a five-month-old caucasian child in completely well-being was diagnosed with sex cord stromal tumour not elsewhere classified (NOS) and underwent orchifunicolectomy with inguinal approach. During the clinical and radiological follow-up no recurrence was diagnosed. Therefore, our case report could be a useful clinical and surgical example for paediatric surgeons in order to successfully treat a sex cord stromal tumour not elsewhere classified (NOS).