Testicular tumour. This young man presented with a left scrotal mass. An ultrasound image of his asymptomatic right testis is provided on the left, showing the typical appearance of a normal testis – ovoid in shape and uniform in echogenicity. On the right is an image of the left testis – it is enlarged, irregular in shape and heterogeneous in echogenicity. The testis was removed and was found to have been completely replaced by germ cell tumour.