1. Radiologic features of ( Uremic)leontiasis ossea Dr Mohammad Asif Dogar King Faisal Specialist Hospital and Research center Control #: 1827 Poster #: EE-16

2. Disclosure None

3. Patient # 1

4. Patient # 2

5. Purpose To discuss characteristic radiologic features of uremic leontiasis ossea.

6. Case Report We present case report of two patients (12-year-old girl and 29- year-old male) presenting with jaw masses. Both of these patients had known diagnosis of renal failure and they were on hemodialysis. They presented at King Faisal Specialist Hospital and Research Center Riyadh with gradual onset of mass lesion involving mandible.

7. Imaging Findings Facial skeletal changes associated with hyperparathyroidism are encountered infrequently and assume three radiographic patterns

8. Imaging Findings The classic form is termed "osteitis fibrosa cystica" and presents with a combination of increased bone cell activity, peritrabecular fibrosis, and cystic brown tumors. Radiographically, this appears as a constellation of cortical thinning of multiple bones, coarsened trabecular patterns, osteolytic lesions, and "salt-and- pepper" appearance of the skull, which is the result of mixed osteolytic and sclerotic bone.

9. Imaging Findings The second form resembles fibrous dysplasia, with a classic ground-glass pattern on both conventional films and CT. Unlike true fibrous dysplasia, these findings can be diffuse and generalized, with poor corticomedullary distinction, an imaging finding not present in fibrous dysplasia

10. Imaging Findings The third and the rarest form is uremic leontiasis ossea (1-2). In our patients CT scan was obtained which shows mass-like lesions in mandible and maxilla. These lesions in both patients have peculiar pattern of serpentine channels or trigroid appearance. Other features of renal osteodystrophy including diffuse calvarial thickening and subchondral resorption also were present. Ultrasound examination showed enlarged parathyroid glands in both of them.

11. Patient # 1 Diffuse bony thickening Poor corticomedullary differentiation Mass like lesion with wavy/serpentine pattren

12. Resorption of bilateral mandibular condyles Bony thickening Ground glass appearance

13. Mass like lesion in mandible with typical trigroid or serpentine pattern Ground glass appearnace

14. Bony thickening loss of corticomedullary differentiation Mass like lesions in mandible and maxilla with peculiar pattern

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18. Patient # 2

19. Mass like lesions in mandible and maxilla with peculiar serpentine channels

20. Hypertrophy of mandible and maxilla Mass like lesions with serpentine channels Loss corticomedullary differentiation

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24. Summary Uremic leontiasis ossea is a rare disorder but has characteristic imaging findings. Familiarity with these findings can help in diagnosis and avoid unnecessary biopsy and further work up.

25. References Reference One: J.I Chang, P.M Som and W lawson, et al. Unique imaging findings in the fascial bones of renal osteodystrophy. AJNR Am J Neuroradiol 2007;28:608-609 Reference Two: Aggunlu L, Akpek S, Coskun B. Leontiasis ossea in a patient with hyperparathyroidism secondary to chronic renal failure. Pediatr Radiol 2004;34:630–32