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A previously healthy 13-year-old female adolescent presented with right retrobulbar eye pain, worse with vertical eye movements, followed by decreased visual acuity, evolving for 4 days. She complained of fatigue in the previous month and she reported no similar previous episodes. On admission, she had mild visual loss (0.8) in the right eye with a relative afferent pupillary defect, blurring of optic margins of the right papilla and a right central scotoma. She showed no dyschromatopsia and no other changes in the neurological examination. The brain MRI showed two tumefactive demyelinating lesions with an open-ring enhancement after gadolinium administration (figure 1) and additional typical demyelinating lesions (disseminated in space) without enhancement. Cerebrospinal fluid analysis showed no changes, oligoclonal banding was negative and anti-AQP4 and anti-MOG antibodies were negative. These findings were consistent with multiple sclerosis (MS) with pseudotumoral demyelinating lesions (MS-PL) and she completed 5 days of intravenous methylprednisolone, with full visual recovery. At the follow-up consultation, she started intravenous natalizumab. She showed regression of previous lesions and no new injuries in subsequent MRI at 6, 12, 18 and 36 months. Three years after diagnosis, she is clinically stable (Expanded Disability Status Scale: 1.5), with no new relapses or complaints related to treatment.
MS, defined by recurrent episodes of demyelination in the central nervous system (CNS), disseminated in space and time, is the most prevalent chronic inflammatory disease of the CNS. In children, it has a wide range of clinical manifestations, including optic neuritis, or a range of focal or multifocal neurological symptoms. In this case, although the clinical presentation was limited to ocular symptoms, brain MRI showed large demyelinating lesions. Typical MS lesions identified in MRI are usually smaller than 0.6 cm.1 Rarely, some patients present with larger demyelinating lesions at their first event. When larger than 2 cm, these lesions are considered tumefactive or pseudotumoral.2–4 Although rare (incidence of 3:1 000 000/year), MS-PL is more common in women in their second and third decades of life and is usually manifested by multifocal symptoms such as persistent headache, impaired consciousness, focal signs or cognitive deficits.2 5 Surprisingly, in our case, it occurred with few neurological deficits disproportionate to the lesion dimensions. MS-PL may pose diagnostic challenges: solitary lesions may be mistaken for primary tumours, abscess, metastasis or infarction, while multiple pseudotumoral lesions may suggest acute disseminated encephalomyelitis.2–9 In our case, the presence of additional typical demyelinating lesions fulfilling McDonald’s criteria for dissemination in time and space assisted in diagnosing MS.
MS-PL is associated with higher hospitalisation rates and morbidity than conventional MS.10 Due to its significant inflammatory component, it may respond to corticosteroids, as shown in our case, with a reduction of the size of the lesions.9 Although its long-term evolution is still unclear, the complete disappearance of the lesions is unusual and residual deficits are frequent.10 Recurrence of pseudotumoral lesions, although uncommon, may occur.6 The present case adds up to the few cases that have been described in the literature and may contribute to further understand the clinical picture of MS-PL in children and adolescents.
Multiple sclerosis with pseudotumoral demyelinating lesions (MS-PL) is a rare variant of the disease and it can represent a diagnostic problem.
MS-PL may present with clinical features disproportionate to the lesion dimensions and may show a good prognosis despite the great size of lesions.
Contributors CSdS and FP contributed to the study conception and design. BCG and FP contributed to acquisition and interpretation of the images and data. The first draft of the manuscript was written by CSdS and all authors commented on previous versions of the manuscript and revised it critically for important intellectual content. All authors read and approved the final manuscript and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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