The authors report the case of a one-year-old infant in whom routine examination by the paediatrician demonstrated left testicular swelling. Subsequent assessment (scrotal ultrasound and laboratory tests) revealed only a moderate increase of alpha-foetoprotein levels. Orchidectomy was performed due to a suspicion of vitelline tumour. Histological examination revealed splenogonadal fusion. In the light of this case, the authors discuss the modalities of early diagnosis of this embryonic anomaly for which orchidectomy appears to be excessive, even when the testicular parenchyma has an immature appearance.