Uremic leontiasis ossea: A pictorial review of a rare complication of renal osteodystrophy

Uremic leontiasis ossea is a very rare manifestation of renal osteodystrophy with associated secondary or tertiary hyperparathyroidism, resulting in a diffuse and symmetrical enlargement of the craniofacial bones.
Although its pathophysiology remains uncertain, it seems that hyperphosphatemia and hypocalcemia secondary to chronic renal failure are the most likely precipitating factors.
Information regarding this disease consists mainly of case reports in the literature and some small series.
We describe four patients with ESRD on hemodialysis who had chronic progressive facial deformities and underwent imaging of the head and neck for further evaluation.
The aim of this work is to describe the characteristic imaging appearance of ULO and provide a broad review regarding its physiopathology, clinical presentation, biological assessment and treatment.
Knowledge of this disease is essential for every clinician involved in treating ESRD patients since treatment options aim to control hyperparathyroidism, resulting in stabilization of the facial deformities in most cases.