Uremic Leontiasis Ossea: A Rare Presentation of Chronic Renal Failure Secondary to Hyperparathyroidism

Abstract

Facial skeletal changes associated with hyperparathyroidism assume three radiographic patterns: osteitis fibrosa cystica, fibrous dysplasia, and leontiasis ossea. The 3rd pattern is unique to renal osteodystrophy. Renal osteodystrophy frequently affects the spine, ribs, long bones, and skull. Findings of renal osteodystrophy in facial and cranial bones are rare. However, it’s most severe osseous complication is characterized by massive thickening of the cranial vault and facial bones, called uremic leontiasis ossea (ULO), with only few cases reported in the literature. The uremic leontiasis ossea causes significant aesthetic and functional changes. It is important to recognize features of leontiasis ossea, as it may result in life threatening upper airway obstruction and compressive cranial neuropathy while after parathyroidectomy, facial changes can be stabilized or improved mildly. We report a case of uremic leontiasis ossea with a history of gradual enlargement of the facial bones over a period of one year. Significant hypertrophy of the maxilla and clavarial bone is most significant CT finding with serpiginous tunneling within the bone and poor visualization of the cortical bone. Nuclear medicine scans are also useful for demonstrating parathyroid adenoma. Ultimately, the diagnosis of uremic leontiasis ossea can be made non-invasively through a combination of clinical parameters and imaging findings, as described in this article.