 presenting neuro radiology case 8. This was a 21 years old female who presented with sudden loss of vision in left eye and right-sided weakness. So an MRI of the brain was done which showed that there was a large oval lesion within the periventricular white matter on left side. It classically showed irregular concentric areas of alternating hyper and iso intense signal on flare and T2W images which correspondingly appear iso to hypo intense on T1 weighted images. In addition to this lesion there were few other discrete hyper intense foci within the periventricular and subcortical white matter bilaterally on flare and T2W images. This large periventricular white matter lesion did not show any significant perilegional edema or any significant mass effect. On diffusion weighted images patchy areas of restricted diffusion were seen within it predominantly within the outer ring appearing bright on DW images and turning subtly dark on corresponding ADC maps. No blooming was seen on GR images to suggest hemorrhage or calcification. This is a flare sagittal image which classically shows the concentric irregular alternating signal intensity lesion within the periventricular white matter. In addition few periventricular white matter and posterior foci hyper intense foci were also seen. These are the flare and T2W images which show additional oval hyper intense foci on the left side. This is a post contrast study which shows a classical open ring enhancement within the lesion. A peripheral ring of enhancement is seen which is open inferiorly. Rest of the lesions did not show any post contrast enhancement. Because the patient had vision loss in the left eye MRI of the orbit was also done and these are coronal stir images which show that there is hyper intense signal within the left optic nerve in its intra orbital portion. On post contrast study no significant enhancement was seen within the optic nerve. Also the entire spinal cord was screened which did not show any T2 hyper intense foci within the cord. So to summarize there is an incomplete ring enhancing lesion with a classical onion bulb appearance in the left parieted periventricular white matter. Considering the large size of the lesion no significant mass effect is seen. Also there are few discrete small left periventricular white matter and posterior foci T2 hyper intensities and left optic neuritis. So these classical imaging features are suggestive of bellows concentric sclerosis with probably associated multiple sclerosis. So bellows concentric sclerosis is a demyelinating inflammatory disease and it is considered as a variant of multiple sclerosis. Sometimes you can get other features of multiple sclerosis associated with it as were seen in our case. So in this condition you get round to oval lesion with alternating rings of hyper and hypo attenuation giving it a characteristic bull's eye or onion bulb appearance due to alternating layers of demyelination and preserved myelin. On MRI on a T1 weighted images you get concentric areas of ISO and low signal. On T2 weighted images these areas appear ISO to hypo and hyper intense. On post contrast study peripheral or ring enhancement is seen in the area of active demyelination. Also if there is active demyelination you could get restricted diffusion predominantly in the outer ring. This condition is treated with steroids as was done in our patient. After starting steroids the patient clinically improved and follow up imaging also showed resolution of few of the lesions. So in this case the differential diagnosis which could be considered a balanced tumor factor demyelination considering the large size of the lesion or ADEM or sometimes rarely neoplasms such as a glioma. However, all of these conditions would lack the classical concentric appearance which is seen in this condition. Thank you.