23rd December 2021

A 54-year-old man presents to his GP with a three-week history of lower back and flank non-tender pain

A 54-year-old man presents to his GP with a three-week history of lower back and flank non-tender pain that has worsened gradually. On further questioning, this pain radiates to the patient’s groin. CT shows an irregular mass beside the psoas muscle. He is apyrexial. What is the most likely diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.