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|LETTER TO EDITOR
|Year : 2018 | Volume
| Issue : 4 | Page : 1172-1174
Tigroid and leopard skin appearance in acute disseminated encephalomyelitis
Sunil Pradhan, Animesh Das
Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
|Date of Web Publication||18-Jul-2018|
Dr. Sunil Pradhan
Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow - 226 014, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Pradhan S, Das A. Tigroid and leopard skin appearance in acute disseminated encephalomyelitis. Neurol India 2018;66:1172-4
Tigroid and leopard skin pattern in magnetic resonance imaging (MRI) of the brain were previously thought to be specific for inherited dysmyelinating or hypomyelinating disorders. Acquired disorders have not been described to show such specific MRI patterns. The first case of an acquired disorder such as acute disseminated encephalomyelitis (ADEM) with tigroid and leopard pattern on MRI brain is being presented to reiterate the low specificity of these MRI findings for dysmyelinating disorders such as metachromatic leukodystrophy.
A 40-year old female patient presented with left homonymous hemianopia and recent memory loss for 4 days. She had one episode of left focal seizure along with altered sensorium for 2 days at the onset of illness. There was a viral prodrome of fever and sore throat 1 week prior to the onset of illness. T2 sagittal sections of MRI brain revealed tiger-like strips radiating from the corpus callosum outwards towards the cortex [Figure 1] and [Figure 2]. Axial sections revealed multiple T2/fluid attenuated inversion recovery white matter hyperintensities in bilateral centrum semiovale and right temporal region [Figure 3]. These T2 hyperintensities had multiple hypointensities in between, resembling leopard skin appearance, as described classically in metachromatic leukodystrophy and other inherited demyelinating disorders. She was diagnosed as a case of ADEM and was started on steroids. Cerebrospinal fluid analysis showed mildly raised protein (68 mg/dl) with few cells (10 lymphocytes). She had complete improvement of the symptoms in the next 4 weeks. Steroids were tapered and stopped on the follow-up visit. A repeat MRI of the brain after 3 months showed complete resolution of the lesions. Multiple T2 white matter hyperintensities along with resolution of the lesions after steroid therapy, in the background of a clinical history of altered sensorium with neurological deficits, suggest a demyelinating pathology like ADEM as the cause of the patient's symptoms.
|Figure 1: Midsagittal T2 section of MRI brain showing the tigroid pattern of demyelination|
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|Figure 2: Parasagittal T2 section of MRI brain showing the tigroid pattern of demyelination|
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|Figure 3: Axial T2 image of MRI brain showing the leopard pattern of demyelination|
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Tigroid and leopard skin appearance of dysmyelination has been classically described in inherited diseases such as metachromatic leukodystrophy (MLD) and Pelizaeus–Merzbacher disease (PMD). Of late, these specific MRI patterns have been described in other inherited diseases such as globoid cell leukodystrophy, infantile GM1 gangliosidosis, Alexander disease, and Lowe's syndrome.,, Histopathologically, GM1 gangliosidosis shows preservation of perivenular white matter as seen in MLD and PMD, while globoid cell leukodystrophy shows perivenular clusters of lipid storing globoid cells. The tigroid pattern of Alexander's disease is supposed to be due to perivascular Rosenthal fiber deposition. Leopard-like honeycomb appearance has also been described with Canavan disease.
ADEM is an acquired demyelinating disease. Axons within the demyelinated areas are predominantly preserved. According to the available literature, ADEM results from a transient attack against myelin by autoreactive T cells. Molecular mimicry or nonspecific activation of T-cells by bacterial or viral super-antigens remains the underlying cause of such an attack. Demyelination along with perivenular mononuclear cell infiltration results. As such, ADEM produces white matter demyelination, which would appear bright on T2-weighted images. As mononuclear cell infiltration is known to produce hypointensity on T2, their accumulation in perivenular location may appear as linear hypointensities on sagittal sections. Veins run perpendicular to the brain surface within Virchow-Robin spaces. Thus, perivenular inflammatory response and demyelination may give rise to alternate gray and white stripes on sagittal images resulting in the tigroid appearance on MRI. Understandably, this would give rise to leopard skin-like appearance in the axial plane.
To the best of our knowledge, this is the first case describing the appearance of tigroid or leopard skin appearance in acquired demyelinating diseases. We can thereby say that these classical MRI patterns should be interpreted with care for the specific diagnosis of a disease and clinical profile of the patient should always be taken into account.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initial will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]