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|Year : 2017 | Volume
| Issue : 3 | Page : 558-560
Tumefactive acute disseminated encephalomyelitis
Sunil Pradhan, Surjyaprakash S Choudhury, Animesh Das
Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
|Date of Web Publication||9-May-2017|
Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareli Road, Lucknow, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Tumefactive demyelinating lesions are tumour-like presentations of acute demyelinating lesions. They have been described with multiple sclerosis only and not with other varieties of acquired demyelination like acute disseminated encephalomyelitis (ADEM). The uncertainty about the diagnosis at the onset of the disease in tumefactive ADEM makes it important that the physicians should be aware of this entity. Various radiological similarities with more sinister lesions like central nervous system gliomas or lymphomas may lead to this confusion. Appropriate supportive treatment with steroids and follow up is required in these cases to avoid unnecessary interventions.
Keywords: Acute disseminated encephalomyelitis, inta-axial glial neoplasm, magnetic resonance imaging, tumefactive demyelinating lesions, tumefactive acute disseminated encephalomyelitis
Tumefactive acute disseminated encephalomyelitis can mimic central nervous system neoplastic lesions
|How to cite this article:|
Pradhan S, Choudhury SS, Das A. Tumefactive acute disseminated encephalomyelitis. Neurol India 2017;65:558-60
Tumefactive demyelinating lesions, being the radiological mimickers of high-grade central nervous system neoplasms, often cause a diagnostic dilemma for clinicians as well as radiologists. Timely suspicion and careful follow-up with therapeutic interventions and magnetic resonance imaging (MRI) may save these patients from unnecessary biopsy or surgery. Among the demyelinating diseases, multiple sclerosis is well-known to present in rare instances with tumefactive lesion. This tumor-like presentation is not known with other demyelinating disorders. We present three patients with tumefactive acute disseminated encephalomyelitis (ADEM).
| » Case Reports|| |
A 35-year old female patient had tingling and paresthesia on the left half of her body. There was slight weakness on the left side that was persisting since the acute hemiparesis that she developed about 6 years back. This acute stroke-like illness evolved within a period of 24 h with alteration of consciousness that lasted about a week. MRI done during the acute phase was suggestive of a large mass lesion in the right frontal lobe extending to involve the left frontal lobe along the corpus callosum with surrounding vasogenic-edema [Figure 1]. The lesion mimicked a butterfly glioma. She was given supportive treatment in the form of steroids, and when her sensorium improved, she was taken up for biopsy, which revealed active demyelination with glial proliferation and infiltration by foam cells. At the time of presentation to us, power in the left upper limb and lower limb was 4/5 on the Medical Research Council (MRC) scale at all joints. Repeat MRI done after 3 years for persistent pain showed near complete resolution of the right frontal lesion [Figure 1]. As there was no clinical or radiological recurrence in 6 years, a diagnosis of tumefactive ADEM was kept. She was managed with drugs for neuropathic pain and physiotherapy.
|Figure 1: Magnetic resonance image of the brain at presentation showing a large mass lesion in the right frontal lobe extending to involve the left frontal lobe along the corpus callosum with surrounding vasogenic edema (left side) and the follow up image showing complete resolution of the lesion (right side)|
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A 37-year-old school teacher presented with acute-onset speech difficulty and delirium for 3 days. She could comprehend words but speech output was of low volume and nonfluent. Repetition and naming were also impaired. She did not have vascular risk factors for stroke. She had never experienced similar illness, either transient or permanent, in the past. Examination or laboratory investigations did not reveal any evidence of systemic vasculitis. The neurological examination was normal except for the speech abnormality. suggesting Broca's aphasia. MRI of the brain revealed a well-defined T1 hypointense and T2 hyperintense mass lesion in the left posterior frontal region with minimal contrast enhancement in the periphery [Figure 2]. There was no midline shift or any other evidence of mass effect. No restriction was seen on diffusion-weighted image. Cerebrospinal fluid (CSF) was normal with no oligoclonal bands. Somatosensory and visual evoked potentials were also normal. Magnetic resonance spectroscopy (MR) study of the lesion showed increased choline with decreased creatinine and NAA level, suggestive of a neoplastic lesion. She was referred to the neurosurgery department, but during the preoperative workup, she started improving. She was referred to the neurology department, and thereafter, she was started on steroids in tapering doses for 6 weeks. Her improvement continued. At the time of follow-up after 2 months, her aphasia had resolved completely and repeat MRI showed significant resolution of the lesion [Figure 2]. The disease course and its response to steroids as well as the resolution of the lesion in the follow-up MRI after 3 months favor a demyelinating pathology.
|Figure 2: Magnetic resonance image of the brain at presentation revealing a T2 hyperintense mass lesion in the left posterior frontal region without edema or mass effect (left side) and follow up MRI (right side) showing significant resolution of the lesion|
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A 33-year-old sportsperson presented with acute-onset headache and vertigo followed by gradually progressive altered sensorium reaching a nadir in 6 h. There was a history of fever and sore throat 8–10 days before the onset of the present illness. On the day of the examination, he had mildly altered consciousness. There was no focal motor weakness or cranial nerve deficit. Generalized hyper-reflexia was noted. MRI of the head showed ill-defined T2/fluid-attenuated inversion recovery (FLAIR) hyperintense and T1 hypointense lesion in the left occipital lobe with minimal mass effect causing obliteration of the left occipital horn of lateral ventricle [Figure 3]. The lesion showed mild contrast enhancement and no diffusion restriction. MR angiogram and MR venogram were normal. Possibility of tumefactive ADEM was kept, and the patient was given intravenous methylprednisolone followed by tapering doses of oral steroids for 8 weeks. His sensorium improved in the next 7 days and he was discharged. Follow-up MRI brain after 3 months showed complete resolution of the lesion [Figure 3].
|Figure 3: Magnetic resonance image of the head at presentation (right side) showing an ill-defined T2 hyperintense lesion in the left occipital lobe with minimal mass effect causing obliteration of the left occipital horn of lateral ventricle and follow up MRI brain (left side) after 3 months showing complete resolution of the lesion|
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| » Discussion|| |
Primary demyelinating diseases of the central nervous system (CNS) encompass three broad entities: (1) acute disseminated encephalomyelitis (ADEM) and its variant acute hemorrhagic leukoencephalitis (AHLE or Weston–Hurst syndrome), (2) multiple sclerosis (MS) and its variants (tumefactive MS, Marburg variant, Balo concentric sclerosis, Schilder disease/myelinoclastic diffuse sclerosis), and (3) neuromyelitis optica (NMO) including NMO-spectrum disorders. Tumefactive demyelinating lesions are usually solitary white matter lesions that are >2 cm in diameter and mimic primary or secondary brain tumors. It is important to distinguish between these two conditions because treatment options are completely different and prognosis may also vary. Small nuances in noninvasive techniques like MRI with some specific modalities, such as perfusion studies and MRS, can help significantly in managing these lesions. Thus, invasive methods such as biopsy may not be required. The first case in our case series had in fact undergone biopsy as the MRI features of contralateral hemispheric spread with corpus callosal involvement were more in favor of a highly aggressive CNS neoplasm.
According to the available literature, MRI features that favor a diagnosis of tumefactive demyelinating lesion include a large irregular white matter lesion with little mass effect and vasogenic edema, with diffusion restriction on diffusion weight images (DWI), minimal midline shift, open ring enhancement with ring opening towards the gray matter, low cerebral blood volume on perfusion studies, and venules running through the centre of lesions on T2-weighted images.,, Involvement of other white matter areas of the brain also favors a demyelinating pathology. MRS can be helpful in doubtful cases as acute demyelinating lesions show an increased choline peak and decline in N-acetyaspartate (NAA) peak. Some cases may have increase in lipid and lactate. High-grade CNS tumors such as a high-grade glioma or CNS lymphoma exhibit increase in choline levels and decrease in NAA/creatine ratio. Elevation of glutamine/glutamate is a strong point in favor of tumefactive demyelinating lesions as gliomas seldom show this peak. Other features such as central necrosis, variable enhancement pattern, lesions at the junction of gray white matter or gray matter, significant vasogenic edema, or midline shift are common to primary CNS tumors. We could not perform special sequences such as perfusion assays in any of our patients. Even MRS done in one patient did not reveal the special glutamine/glutamate peak, and therefore, we referred that patient to neurosurgery for possible surgery; however, fortunately she started improving before any intervention could be done.
Even with so many differences between tumefactive demyelinating lesions and high-grade CNS tumors, the diagnosis may be confusing in many cases. Biopsy remains the gold standard method to differentiate between the two pathologies. Acute demyelinating lesions show preservation of axons, which can be documented by presence of neurofilaments, negative lugol's staining signifying loss of myelin, presence of macrophages as shown by positivity for CD68, and proliferation of astrocytes which can be demonstrated by positivity for glial fibrillary acidic protein. Biopsy done in the first case was supportive of the fact that the lesion had a demyelinating pathology.
| » Conclusion|| |
All of the cases signify that clinicians need to be particularly aware of the entity of tumefactive ADEM, which is not yet a well-defined entity. Tumefactive multiple sclerosis has been described in literature; however, tumefactive ADEM, which represents another spectrum of tumefactive demyelinating lesions, is not yet known. We propose this new entity and hope that neurophysicians will not miss these cases.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]