1. NR8

2. INTRODUCTION  A rare multisystem non Langerhans cell histiocytosis  First described by Jakob Erdheim and William Chester in 1930  Since then less than 100 cases have been reported  Defined by the xanthomatous or xanthogranulomatous infiltration of tissues with foamy histiocytes, surrounded by fibrosis.

3.  Clear increase in its incidence due a better understanding of its radiological semiology.  The aetiology remains unknown  The disease can affect multiple organs systems, including musculoskeletal, central nervous, cardiac, pulmonary and renal systems  The most common neurologic manifestation is central diabetes insipidus.

4.  We report the case of adult-onset ECD with neurologic involvement  To study the MRI appearance of neurological lesions

5. Materials and methods :  A 50 year old woman  Consulted for a polyuria-polydipsia syndrome  Physical examination was normal except the presence of a xanthelasma lesions on the eyelids  A water restriction and a DHA test concluded to a central diabetes insipidus  X -Rays, Brain MRI centered on the hypothalamic- pituitary axis were performed

6.  Femur X –rays: Symmetric metaphyseal osteosclerosis  MRI brain showed: Diffuse infiltration of the pituitary stalk massively enhanced after gadolinium injection Disappearance of the normal T1 hyperintensity of the post hypophysis

7. Pituitary MRI, coronal T1: Homogeneous diffuse thickening of the pituitary stalk Normal cavernous sinus ( )

8. Pituitary MRI, coronal T1 GADO: Diffuse intense enhancement of the pituitary stalk( )

9. Pituitary MRI, sagittal T1GADO: Diffuse thickening of the pituitary stalk massively enhanced with gadolinium Homogeneous enhancement of the posterior hypophysis

10.  Characterestic radiological findings +  Histological features (a skin biopsy ) with a proliferation of foamy histiocytes that stain for CD68 but not CD1a Confirmed the diagnosis

11. Discussion  ECD is a rare disease  A non-Langerhans' cell histiocytosis  Defined by infiltration of foamy lipid-laden histiocytes that stain positively for CD68  With characteristic radiological and histological features

12. Discussion Extraskeletal manifestations including involvement of:  Hypothalamus-pituitary axis: diabetes insipidus  Lung :diffuse pulmonary fibrosis  Heart  Retroperitoneum  Skin  Orbit  Liver, Kidneys, Spleen

13. Discussion Characterized by a bilateral symmetric sclerosis of the diametaphyseal regions of long bones Radiographic studies reveal:  Bilateral, patchy or diffuse increase in density  Sclerosis, and cortical thickening  Mainly in the metaphyses  Minor changes or sparing of the epiphyses

14. Discussion Neurologic Manifestations:  The most common neurologic manifestation is a central diabetes insipidus  The hypothalamic location was found in 40% of intracranial locations  Next in frequency is cerebellar symptoms, usually ataxia of gait.

15. MRI of the brain in patients with neurologic symptoms demonstrates:  Intra-axial lesions with T2 hyperintensity  Often intense gadolinium enhancement  The MRI findings mimic a demyelinating process and are often confused with multiple sclerosis

16. The MRI findings in patients with diabetes insipidus vary:  Often no structural changes are seen  Loss of the normal T1 hyperintensity of the posterior pituitary  Pituitary enhancement  Enlargement of the infundibulum

17. Orbital Manifestations Infiltration of the retroconal fat Optic nerve sheath Retrobulbar, intraconal masses Retroperitoneal Manifestations Fat stranding Soft tissue masses Hydronephrosis leading to renal failure and hypertension Periaortic fibrosis

18. Pulmonary Manifestations: The most common symptom is progressive dyspnea  Chest X-Rays :diffuse interstitial prominence and pleural thickening  CT typically shows: interlobular septal pleural thickening patchy centrilobular ground glass opacities

19. Prognosis and Therapy:  Related to the extent of visceral involvement  Most patients die within two to three years after diagnosis congestive heart failure, lung fibrosis or renal insufficiency  Treatment options: corticosteroids, radiotherapy, combination therapy  None have been highly effective  The disease is typically relentless in its course

20. Conclusion: Erdheim Chester disease is a rare non-Langerhans Histiocytosis Characterized by a bilateral symmetric sclerosis of the diametaphyseal regions of long bones With various extraskeletal manifestations The hypothalamic location was found in 40% of intracranial locations The typical features on imaging are often the basis of diagnosis, and should be well known The disease is typically relentless in its course.

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