Bahrain Medical Bulletin, Vol. 37, No. 3, September 2015 Moyamoya Disease in Patient with Multiple Sclerosis Foziah Al Shamrani, MD* Fahad Al-Khamis, MD** Ibrahim Al Ghanimi, MD*** Inam Khuda, MD**** Danah Al Jaafari, MD***** Majed Alabdali MD****** Moyamoya disease is a rare progressive disease characterized by irreversible cerebrovascular occlusion. The occlusion would lead to an opening of transcortical, transdural collateral vessels. As a sequelae of this occlusion, ischemic and rarely hemorrhagic stroke happen leading to significant brain damage. We present a unique case of a 16-year-old female with a history of relapsing-remitting multiple sclerosis presented with recurrent ischemic stroke secondary to Moyamoya disease. MRI/MRA of this patient shows the typical features of Moyamoya disease. ___________________________________________________________________________ * Assistant Professor ** Assistant Professor *** Assistant Professor **** Assistant Professor ***** Neurology Specialist ******Neurology Specialist Neurology Department King Fahd University Hospital Kingdom of Saudi Arabia Email: fo0og@hotmail.com; fshamrani@edu.uod.sa Moyamoya disease is a chronic occlusion of a major vessel of the circle of Willis leading to opening of cerebral collaterals. Moyamoya is common in Japan, but cases from Europe and America were reported 1 . Its etiology could be idiopathic (primary Moyamoya), secondary (inherited), hematological and post infections 2 . It has a special characteristic appearance in the angiography described as “puff of smoke” 3 . Multiple sclerosis (MS) is an inflammatory disease of the white matter of the brain characterized by relapsing neurological symptoms. The masquerade between those diseases is high, but the clinical, radiological and laboratory investigations confirm that both pathologies were present in our patient, although this is not reported before 4 . The studies emphasize early consideration of Moyamoya in the differential diagnosis of MS-spectrum disorders, which shares many features 4,5 . The aim of this presentation is to present a rare possible clinical and radiological association between Moyamoya disease and multiple sclerosis. THE CASE A sixteen-year-old single female had a history suggestive of relapsing, remitting MS. A year ago, she had three episodes of numbness where she recovered completely and her diagnosis was supported by radiological and laboratory findings. Recently, the patient presented with a 3-day history of left upper limb weakness and facial asymmetry. CT brain and MRI were performed to confirm the diagnosis and rule out MS relapse. CT scan and MRI confirmed the