Renal primitive neuroectodermal tumour (PNET) is a rare malignant tumour of paediatric patients. We describe the important imaging findings, including the ultrasound, CT and MRI of a case of renal PNET in a teenager. To our knowledge, some findings have not been described previously. Some features that have been considered as characteristic are not present in our case, and it is, to our knowledge, the first documented case with such extensive tumour thrombus. We also demonstrate the importance of including PNET as a differential diagnosis because combined chemotherapy is thought to be the best first-line treatment in most cases. Histological diagnosis can be determined by a minimally invasive procedure instead of laparotomy or open biopsy.