Precocious puberty related to Leydig cell testicular tumor: the diagnostic imaging keys

BACKGROUND: We report the challenging case of a 6-year-old boy with precocious puberty related to histologically proven Leydig cell tumor. CASE PRESENTATION: Multiparametric ultrasound and magnetic resonance imaging (MRI) was performed. Interesting findings were scarcely or never reported in children and differed from adults Leydig cell tumors s such as the hyperechogenic halo surrounding the lesion and the dominant central vascularization using ultrasensitive Doppler. MRI revealed an enlarged testicle with strong enhancement of a tumor, a tumor apparent diffusion coefficient (ADC) of 600 × 10(−3) mm(2)/s and a lower ADC value of the non-tumor parenchyma compared to the contralateral testis (ADC = 800 × 10(−3) mm(2)/s vs 1100 × 10(−3) mm(2)/s), attributed to the spermatogenesis induced by hormonal impregnation. CONCLUSION: We illustrate multiparametric US and MRI findings of a pediatric Leydig cell tumor, including the imaging changes attributed to local hormone secretion, which may be helpful in similar cases.