Radiological Category Neuroradiology Principal Modality 1 MRI Principal

Radiological Category: Neuroradiology Principal Modality (1): MRI Principal Modality (2): Case Report # 747 Submitted by: Peter Sedrak, MD Faculty reviewer: Matthew Debnam, MD, M. D. Anderson Cancer center Date accepted: 3 January, 2011

Case History The patient is a middle aged female with Fatigue and Altered Mental Status.

Radiological Presentations

Test Your Diagnosis Which one of the following is your choice for the appropriate diagnosis? After your selection, go to next page. • Multiple Meningiomas • Dural Metastases • Erdheim-Chester Disease

Findings and Differentials Findings: Axial T 1 -Post contrast MRI shows multiple avidly enhancing extra-axial dural based masses. Differentials: • Multiple meningiomas • Dural metastases • Erdheim-Chester Disease

Discussion This patient had multiple extra-axial masses. In all actuality all three entities listed in the differential are plausible diagnoses for this case. The actual diagnosis was Erdheim-Chester disease, and the diagnosis for this disease is made histologically. It is indistinguishable from many other entities from an imaging standpoint. Other facts about Erdheim-Chester disease: It is an extremely rare form of non-Langerhans histiocytosis. Patients usually present during middle age, and the most common symptom is Diabetes Insipidus. The most common sites of CNS involvement include the pituitary, the middle cerebellar peduncles, and brainstem. Treatment classically consists of Interferon.

Diagnosis Erdheim-Chester disease.

References Drier A, Haroche J, Savatovsky J, et al. Cerebral, facial, and orbital involvement of Erdheim. Chester Disease. CT and MR Imaging Findings. Radiology 2010; 255: 586 -94.