Renal lobar dysmorphism: a potential mimic of renal malignancy.

A renal pseudotumour is any apparent renal mass that simulates a tumour on radiological imaging but is composed of normal tissue. Renal pseudotumours may be inflammatory, vascular, postsurgical or congenital. We report a case of renal lobar dysmorphism (RLD) of the kidney, a congenital renal pseudotumour. A 45-year-old man presented with scrotal swelling. Testicular ultrasound showed an epididymal cyst. Renal ultrasound showed a right solid renal apparent mass of 2.4 cm in diameter. Triphasic renal CT showed this was consistent with RLD. Intravenous urography confirmed a central calyx within the dysmorphic lobe. RLD is a rare congenital normal anatomical variant, which can appear as a renal pseudotumour. No further investigation or intervention is necessary. We present the radiological findings of RLD and review the literature.