Baló's concentric sclerosis: imaging findings and pathological correlation

Abstract

Baló's concentric sclerosis is a primary inflammatory central nervous system demyelinating disease that is considered a rare, radiographically and pathologically distinct variant of multiple sclerosis. Baló's concentric sclerosis is characterized by alternating rings of demyelinated and myelinated axons, and it is most frequently diagnosed postmortem by autopsy or, more recently, by magnetic resonance imaging without pathologic verification. This report is of a case of Baló's concentric sclerosis in which the patient presented with left-sided focal sensorimotor deficits. The patient's lesion demonstrated characteristics of Baló's concentric sclerosis by magnetic resonance imaging, but since a neoplastic process was also suspected initially, the patient underwent a surgical biopsy. This pathology sample now provides the opportunity to correlate the tissue diagnosis of demyelination with characteristic magnetic resonance imaging findings; this comparison is infrequently found in the literature.

Keywords: Baló’s concentric sclerosis; MRI; Pathology; demyelinating disease.

Figure 1

55 year-old male with Baló’s concentric sclerosis. This axial T1-weighted MR image shows a non-uniform, round mass (circled) with irregular alternating bands of hypointense and isointense signal, representing demyelinated and myelinated areas, respectively. There is surrounding edema and no mass effect. The lesion measures 1.9 cm × 1.6 cm × 1.1 cm in AP, transverse, and craniocaudal directions. This mass is located in the right precentral gyrus, corresponding to the region of the motor strip and hand area. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 468, TE: 12)

Figure 2

55 year-old male with Baló’s concentric sclerosis. This magnified view of the axial T1-weighted MR image shows a non-uniform, round mass (circled) with irregular alternating bands of hypointense and isointense signal, representing demyelinated and myelinated areas, respectively. There is surrounding edema and no mass effect. The lesion measures 1.9 cm × 1.6 cm × 1.1 cm in AP, transverse, and craniocaudal directions. This mass is located in the right precentral gyrus, corresponding to the region of the motor strip and hand area. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 468, TE: 12)

Figure 3

55 year-old male with Baló’s concentric sclerosis. This axial contrast enhanced T1-weighted MR image shows that the areas of demyelination enhance after contrast administration. This enhancement is demonstrated by the hyperintense ring circled in this image. Areas of myelination remain isointense as they were in the non-contrast T1-weighted image. The lesion has surrounding edema but no mass effect. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 657, TE: 12, 18.5 mL of gadolinium contrast given)

Figure 4

55 year-old male with Baló’s concentric sclerosis. This magnified view of the axial contrast enhanced T1-weighted MR image shows that the areas of demyelination enhance after contrast administration. This enhancement is demonstrated by the hyperintense ring circled in this image. Areas of myelination remain isointense as they were in the non-contrast T1-weighted image. The lesion has surrounding edema but no mass effect. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 657, TE: 12, 18.5 mL of gadolinium contrast given)

Figure 5

55 year-old male with Baló’s concentric sclerosis. This axial T2-weighted MR image shows the non-uniform, round mass (circled) with alternating areas of isointense and hyperintense signals, corresponding to myelinated and demyelinated tissue, respectively. There is surrounding edema without mass effect. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 3300, TE: 97)

Figure 6

55 year-old male with Baló’s concentric sclerosis. This magnified view of the axial T2-weighted MR image shows the non-uniform, round mass (circled) with alternating areas of isointense and hyperintense signals, corresponding to myelinated and demyelinated tissue, respectively. There is surrounding edema without mass effect. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 3300, TE: 97)

Figure 7

55 year-old male with Baló’s concentric sclerosis. This diffusion-weighted MR image shows the mass (circled) as a central core of low signal with high signal intensity in intermediate and outer rings. Restricted diffusion, which is shown as high signal intensity, is in areas of active demyelination while areas of facilitated diffusion are represented by low signal intensity. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 3600, TE: 89)

Figure 8

55 year-old male with Baló’s concentric sclerosis. This diffusion coefficient map further confirms the presence of restricted diffusion, which is demonstrated as low signal intensity, in the intermediate ring of the mass (circled). Relatively unrestricted diffusion is shown as high signal intensity. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 3600, TE: 89)

Figure 9

55 year-old male with Baló’s concentric sclerosis. This axial T2-weighted MR image highlights tiny, nonsymmetrical hyperintense foci (circled) that are seen in the periventricular and subcortical white matter and the septocallosal interface. These lesions represent areas of demyelination and support the diagnosis of multiple sclerosis. (Protocol: 1.5 tesla magnet strength, 5 mm slice thickness, TR: 3300, TE: 97)

Figure 10

55 year-old male with Baló’s concentric sclerosis. This sagittal STIR MR image of the cervical spine shows two hyperintense foci that measure 6 mm and 5 mm in diameter (circled) and are located at the level of C2 and C5, respectively. These lesions also represent areas of demyelination and further support the diagnosis of multiple sclerosis. (Protocol: 1.5 tesla magnet strength, 3 mm slice thickness, TR: 4230, TE: 42)

Figure 11

55 year-old male with Baló’s concentric sclerosis. The Luxol Fast Blue/H&E combination stain of the biopsy specimen shows the demyelinated lesion as a hypercellular focus (pink, arrow) bounded by less cellular normal myelinated white matter (stained blue, outlined by yellow lines). There is also Luxol Fast Blue positive debris (myelin fragments) in many of the histiocytes. There is gliosis both within the demyelinated areas and in the surrounding zones with preserved myelin.