Baló\'s concentric sclerosis

JBR–BTR, 2008, 91: 108-109.

BALÓ’S CONCENTRIC SCLEROSIS E. Pelzers1, J.W. Van Goethem2, L. van den Hauwe1,2, H.R. Degryse1, K. Geens3, P.M. Parizel2 Key-word: Sclerosis, concentric

Background: A 24-year-old woman complained of progressive headache and right sided visual disturbances. Previous medical history was unremarkable. Neurological examination did not reveal additional abnormalities.

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1. Department of Radiology, AZ KLINA, Brasschaat, 2. Department of Radiology, Universitair Ziekenhuis Antwerpen, Edegem, 3. Department of Neurology, AZ KLINA, Brasschaat, Belgium

BALÓ’S CONCENTRIC SCLEROSIS — PELZERS et al

Work-up CT scan of the brain (Fig. 1) shows an ill-defined hypodense mass lesion in the left frontoparietal region and discrete rim enhancement after contrast administration. MRI of the brain (Fig. 2), axial FLAIR-image (A) visualized a heterogeneous, hyper-intense “onionlike” layered lesion. An additional small hyperintense lesion adjacent to the right lateral ventricle is seen. Axial T1-weighted image after gadolinium injection (B) shows layered contrast enhancement of the main lesion. No enhancement of the smaller Lesion is noted. MR spectroscopy (Fig. 3) shows increased choline and decreased N-acetylaspartate (NAA) peaks in the lesion (compared to normal brain on the right). On CT, the solitary mass lesion was considered a low-grade tumor until prooven otherwise. On MRI however, the lesion showed a onion-like layered pattern. Moreover, supplementary lesions in the white matter adjacent to the lateral ventricles were detected. Spinal MRI did not show medullary lesions. Radiological diagnosis The diagnosis of Baló’s concentric sclerosis (BCS) – a rare variant of multiple sclerosis (MS)was proposed. It was decided not to perform biopsy, but a therapy based on corticosteroids was started. A significant reduction in lesion volume on a control MR-examination 4 months later was considered as a confirmation of the diagnosis. Discussion Baló’s concentric sclerosis (BCS) is a rare variant of multiple sclerosis (MS). It was first described in 1928 by Joszef Baló, a Hungarian neuropathologist, as “encephalitis periaxialis concentrica”.The clinical course of BCS was considered similar to that of Marburg’s variant of multiple sclerosis, which has a monophasic rapidly progressive course with a fatal

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outcome. Most cases reported involve young adults. Recently, an increasing number of cases have been described as having prolonged survival or spontaneous remission. The clinical course of the disease is very similar to the more classical form (Charcot) of MS. Clinical symptoms include mild cognitive impairment, altered behavior of focal neurological deficits. The typical “onion-like” appearance of the lesion on MRI reflects the pathological findings in which concentric rings of alternating demyelinated and relatively myelin preserved white matter. This pattern is best recognized on gadolinium-enhanced T1weighted imaging. Multiple enhancing concentric rings represent active demyelination, which cause an increased blood-brain barrier permeability. On T2-weighted images, these lesions show a pattern of alternating hypo- and hyperintense rings. On MR spectroscopy, an increased choline peak and a decreased NAA peak are observed. This is an nonspecific finding observed in lesions with increased membrane turnover and neuronal damage. Solitary lesions are a problem to differentiate from tumors, multiple lesions can help in the diagnosis of MS. In the differential diagnosis, other demyelinating lesions such as acute disseminated encephalomyelitis (ADEM) and CNS tumors (gliomas) can be considered. Bibliography 1. Miller D., Barkhof F., Montalban X., et al.: (Alan Thompson, Massimo Filippi). Clinically isolated syndromes suggestive of multiple sclerosis, part I: natural history, pathogenesis, diagnosis, and prognosis. Lancet Neurol, 2005, 4: 281-288. 2. Karaarslan E., Altintas A., Senol U., et al.: Baló’s concentric sclerosis: clinical and radiologic features of five cases. AJNR, 2001, 22: 1362-1367. 3. Iannucci G., Mascalchi M., Salvi F., et al.: Vanishing Baló-like lesions in multiple sclerosis. J Neurol Neurosurg Psychiatry, 2000, 69: 399400.