Multiple sclerosis and Moyamoya angiopathy: Mimic and misdiagnosis.

Moyamoya Angiopathy (MMA) is frequently not considered in differential diagnosis of Multiple Sclerosis (MS). This is the first study to prospectively analyze rate of misdiagnosis of MMA as MS and its clinical implications. Of the 160 angiographically proven MMA, 5 patients had an initial misdiagnosis of MS (3.13%). These 5 cases had female-predominance (80%).Out of the 5 cases, 4 cases (80%) presented with hemiparesis; 3 cases (60%) had an immediate precipitating factor. Radiologically, presence of both periventricular and juxtacortical white-matter-lesions was seen in 4 out of 5 cases (80%);none had infratentorial/spinal lesion, while all 5 cases had presence of "Ivy" sign and abnormal flow voids. Differentiation relies on careful evaluation of clinico-radiological features. MMA should be considered as a rare but important differential to MS.