A scrotal varicocele is a common finding during both a scrotal clinical examination or during the course of a scrotal ultrasound examination and invariably found in the left hemiscrotum. Traditionally when a scrotal varicocele is found, the referring clinician requests a renal ultrasound examination or the sonographer extends the examination to include a renal examination; to exclude a retroperitoneal or renal tumour as the cause for the varicocele. The present article examines the relevance of performing the extended ultrasound examination by reviewing the pathophysiological pathways for the development of a varicocele in the presence of a renal or retroperitoneal tumour; the prevalance of co-existing renal or retroperitoneal tumours and a varicocele; and the male population in whom this extended examination may be necessary. The conclusion from available evidence suggests that a retroperitoneal tumour will manifest in other ways before the development of a varicocele, the young patient with a varicocele will almost never have a retroperitoneal tumour, and only when a varicocele develops in an older patient will an extended examination be relevant. Even then it will be a rare finding and there will be other clinical manifestations of the primary tumour.