DOI: 10.1148/rg.243035135
Best Cases from the AFIP
Hemimegalencephaly1
David D. Broumandi, MD,
Ulrike M. Hayward, MD,
James M. Benzian, MD,
Ignacio Gonzalez, MD and
Marvin D. Nelson, MD
1 From the Department of Radiology, Santa Barbara Cottage Hospital, Pueblo at Bath St, 0689, Santa Barbara, CA 93102-0689 (D.D.B., U.M.H., J.M.B.); and the Departments of Pathology (I.G.) and Radiology (M.D.N.), Childrens Hospital, Los Angeles, Calif. Received May 19, 2003; revision requested June 18 and received July 16; accepted July 17. Address correspondence to D.D.B. (e-mail: dbroumandi@sbch.org).
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Figure 1a. Axial unenhanced (a) and contrast material-enhanced (b) T1-weighted MR images show enlargement of the right cerebral hemisphere, cavitation in the region of the centrum semiovale (arrowhead), and diffuse gyral thickening (arrows) with diminished sulcation, a finding consistent with pachygyria. There are patchy, linear regions of increased signal intensity in the white matter of the right hemisphere. No pathologic enhancement is seen on the contrast-enhanced image (b).
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Figure 1b. Axial unenhanced (a) and contrast material-enhanced (b) T1-weighted MR images show enlargement of the right cerebral hemisphere, cavitation in the region of the centrum semiovale (arrowhead), and diffuse gyral thickening (arrows) with diminished sulcation, a finding consistent with pachygyria. There are patchy, linear regions of increased signal intensity in the white matter of the right hemisphere. No pathologic enhancement is seen on the contrast-enhanced image (b).
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Figure 2a. (a) Axial unenhanced T1-weighted MR image obtained at the level of the basal ganglia shows an enlarged and dysmorphic right cerebral hemisphere. The right basal ganglia are poorly demonstrated. There is moderate mass effect anteriorly (arrow). (b) On a sagittal T1-weighted MR image obtained at the midline, the corpus callosum is poorly seen (arrowhead).
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Figure 2b. (a) Axial unenhanced T1-weighted MR image obtained at the level of the basal ganglia shows an enlarged and dysmorphic right cerebral hemisphere. The right basal ganglia are poorly demonstrated. There is moderate mass effect anteriorly (arrow). (b) On a sagittal T1-weighted MR image obtained at the midline, the corpus callosum is poorly seen (arrowhead).
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Figure 3a. Axial (a) and coronal (b) unenhanced T2-weighted MR images show enlargement of the right cerebral hemisphere. There is diffuse high signal intensity in the white matter, which correlates with histopathologic findings of poor myelination and early cystic changes. The right lateral ventricle is compressed (arrow in b). The cerebellum is symmetrical and appears normal (arrowhead in b).
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Figure 3b. Axial (a) and coronal (b) unenhanced T2-weighted MR images show enlargement of the right cerebral hemisphere. There is diffuse high signal intensity in the white matter, which correlates with histopathologic findings of poor myelination and early cystic changes. The right lateral ventricle is compressed (arrow in b). The cerebellum is symmetrical and appears normal (arrowhead in b).
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Figure 4. Coronal section through the right frontal hemisphere (same orientation as in Fig 3b) shows broad gyri and a thick cortex, particularly in the frontal lobe (solid straight arrow). The occipital lobe has a more normal gyral pattern (arrowhead). The white matter is gliotic and shows areas of mucinous and cystic degeneration (curved arrow). The gray matter-white matter junction is indistinct. The basal ganglia and thalami are small and poorly demarcated. Subventricular gray matter heterotopia is also noted (open arrow).
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Figure 5a. (a) Low-power photomicrograph (hematoxylin-eosin stain) of the cerebral cortex shows a thickened cortex with poor neuronal lamination (between brackets). An increased number of neurons are present in the subcortical white matter (arrow). Large abnormal blood vessels with prominent perivascular spaces are also present in the white matter (arrowheads). (b) High-power photomicrograph (hematoxylin-eosin stain) shows poorly myelinated white matter containing scattered ectopic neurons (solid straight arrow), gliosis with hypertrophic changes (curved arrow), numerous Rosenthal fibers (arrowheads), and vacuolar changes in the white matter. Focally scattered calcifications are also present in the white matter (open arrow).
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Figure 5b. (a) Low-power photomicrograph (hematoxylin-eosin stain) of the cerebral cortex shows a thickened cortex with poor neuronal lamination (between brackets). An increased number of neurons are present in the subcortical white matter (arrow). Large abnormal blood vessels with prominent perivascular spaces are also present in the white matter (arrowheads). (b) High-power photomicrograph (hematoxylin-eosin stain) shows poorly myelinated white matter containing scattered ectopic neurons (solid straight arrow), gliosis with hypertrophic changes (curved arrow), numerous Rosenthal fibers (arrowheads), and vacuolar changes in the white matter. Focally scattered calcifications are also present in the white matter (open arrow).
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Copyright © 2004 by the Radiological Society of North America.
