Pelvic lipomatosis is a benign disorder of unknown aetiology, characterised by deposition of mature fat in the pelvis. It has a variable natural history, manifesting either with symptoms attributable to the lower urinary tract or varying degrees of renal failure. Owing to the mild, non-specific initial symptoms and slow progression, presentation is delayed and patients are often lost to follow-up, only to present with advanced renal failure later on. We report a case of a young patient with pelvic lipomatosis who, after an initial diagnosis, was lost to follow-up for several years and then presented with uraemic encephalopathy. The case highlights the importance of regular follow-up and an early intervention before irreversible changes occur.