|Year : 2017 | Volume
| Issue : 2 | Page : 139-141
Acute demyelinating encephalomyelitis masquerading as a tumor
R Remya, JK Ann, Ani Sreedhar
Little Flower Hospital and Research Centre, Angamaly, Kerala, India
|Date of Web Publication||10-Aug-2017|
Federal City, Flat No: 2057, Tower 2, Karukutty (PO), Ernakulam, Kerala
Source of Support: None, Conflict of Interest: None
A 34-year-old female presented with a history of acute onset severe bilateral defective vision for 2 weeks. Examination revealed visual acuity CFat1 m in the right eye and 6/60 in the left eye. Right eye had Grade 1 relative afferent pupillary defect. Magnetic resonance imaging (MRI) brain was done which showed well-defined T1-hypointense, T2 and FLAIR hyperintense lesion of approximately 1.8 cm × 1.6 cm × 1.7 cm size in the right frontal lobe cortex and underlying white matter with a thin rim of contrast enhancement with well-defined outer border and a cortex broken arc appearance. MR spectroscopy showed increase in choline peak within the enhancing walls of the lesion and no decrease in N-acetyl aspartate peak suggestive of demyelination. Diagnosis of acute demyelinating encephalomyelitis was made and with a course of large dose steroid vision improved dramatically.
Keywords: Acute demyelinating encephalomyelitis, Cortex broken arc appearance, MR spectroscopy
|How to cite this article:|
Remya R, Ann J K, Sreedhar A. Acute demyelinating encephalomyelitis masquerading as a tumor. Kerala J Ophthalmol 2017;29:139-41
| Introduction|| |
Acute demyelinating encephalomyelitis (ADEM) is an uncommon acute inflammatory demyelinating monophasic disorder of the central nervous system characterized by multifocal lesions in the brain and spinal cord. Very rarely it presents as a solitary lesion which simulates a tumor both clinically and radiologically posing a challenge to the clinician.
| Case Report|| |
A 34-year-old apparently healthy lactating female presented with a history of acute onset severe bilateral defective vision for 2 weeks. There were associated headache and eye pain. Her past ocular history was uneventful. Her medical history was significant for a childhood TB, frequent migraine attacks for about 20 years. She had an episode of high-grade fever with severe cough 1 month back, which was treated with oral antibiotics.
Ophthalmological examination revealed visual acuity of CF at 1 m in the right eye and 6/60 in the left eye. Both eyes extra ocular movements were full but painful. The right eye had Grade 1 relative afferent pupillary defect. Anterior segment of both eyes were otherwise normal. Fundus examination showed a cup-disc ratio of 0.2 bilaterally with no pallor or edema. The macula, vessels, and retinal periphery were unremarkable. The intraocular pressure measured was 15 mm of Hg in both eyes. In right eye, color vision was found abnormal. Contrast sensitivity was 0.60 log units in the right eye, 1.35 log units in the left eye. Bjerum's field test showed centrocecal scotoma in the right eye and normal fields in the left eye. Visual evoked potential showed right eye increased latency of P100 wave with reduced amplitude and left eye normal latency of P100 wave with reduced amplitude [Figure 1]. Cranial nerves other than optic nerve were within normal limits. No focal neurological deficits present. Systemic examination showed no specific abnormality.
|Figure 1: Visual evoked potential showing the right eye increased latency of P100 wave with reduced amplitude and left eye normal latency of P100 wave with reduced amplitude|
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Routine blood investigations were within normal limits. Magnetic resonance imaging (MRI) brain was done which showed well-defined T1-hypointense, T2 and fluid-attenuated inversion recovery hyperintense lesion of approximately 1.8 cm × 1.6 cm × 1.7 cm size in the right frontal lobe cortex and underlying white matter [Figure 2]. A thin rim of contrast enhancement with well-defined outer border noted around the lesion with a cortex broken arc appearance [Figure 3]. Neurology consultation was done. MR spectroscopy was advised to differentiate between mass lesion and demyelination.
|Figure 2: Well-defined T1-hypointense, T2-hypointense, and fluid-attenuated inversion recovery hyperintense cystic lesion|
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|Figure 3: Lesion showing a rim of contrast enhancement with cortex broken arc appearance|
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MR spectroscopy done showed increase in choline peak within the enhancing walls of the lesion and no decrease in N-acetyl aspartate peak suggestive of demyelination. Cerebral spinal fluid (CSF) study showed normal parameters, oligoclonal band absent.
Injection methyl prednisolone 1 g daily for 5 days showed dramatic improvement. The patient was discharged with tapering doses of oral steroids. In the follow-up after 2 weeks vision was 6/9 in the right eye and 6/6 in the left eye.
| Discussion|| |
ADEM is an acute widespread demyelinating condition following an infection or vaccination. The inciting event of postinfectious encephalomyelitis in developed countries is frequently reported as nonspecific upper respiratory tract infection, in developing countries measles and other viral infection accounts for the majority of cases. Postimmunization encephalomyelitis is most commonly associated with mumps, measles, and rubella vaccines even though the incidence is only 1– 2/million measles vaccinations.
Although typically involves white matter with multifocal lesions on neuroimaging, lesions in gray matter, especially basal ganglia, thalamus, or even cortical gray matter also seen. Solitary lesions simulating neoplasm or abcess are rarely reported.
The frequently reported pathogenesis is a transient autoimmune response against myelin basic protein through molecular mimicry or by nonspecific activation of an autoreactive cell clone.
Most often seen in children aged <10 years but can also occur in adults 19– 61 years ago with a slight female preponderance. After 4– 21 days of inciting event, systemic symptoms such as fever, malaise, headache, nausea, and vomiting precedes the neurological symptoms. Focal or multifocal neurological signs appear. Optic neuritis is often bilateral.
Recovery begins within days. Greater than 85% make complete recovery. Poor prognosis is correlated with severity and abruptness of onset of syndrome. Adults tend to be more severely affected with worse recovery.
Differentiation of ADEM from first attack of multiple sclerosis has prognostic and therapeutic implication but is quite difficult because of similar features. A viral prodrome, meningism, high lesion load on MRI, lesions of same age with no new lesions after initial clinical attack, deep cortial gray matter involvement, the absence of oligoclonal bands are suggestive of ADEM.
In ADEM, CSF study may be normal or shows increased pressure, lymphocytic pleocytosis, raised protein, gamma globulins; IgG. Treatment is with systemic steroids. In resistant cases, plasmapheresis or IvIg is effective.
| Summary|| |
This patient's presenting symptoms and signs were consistent with retrobulbar neuritis and the imaging showed a frontal lobe lesion simulating a tumor. This case is unique in the atypical imaging findings in ADEM that mimics a tumor. Various clues to the diagnosis where abrupt onset of symptoms and less mass effect than expected for the size of the lesion, arc such as incomplete ring enhancement and no dissemination of lesion in time. MR spectroscopy also guided us to the diagnosis. However, this case emphasises the importance of considering a demyelinating disease as a differential diagnosis in tumor-like lesion on MRI. The combination of MR findings with clinical history, physical examination and laboratory tests is crucial for correct diagnosis.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]