Clinical
Presentation: Patient is a 6-year-old boy with new onset seizure.
Imaging Findings: Bands of heterotopic gray matter extend from the cortical surface along a deep sulcus to the frontal horn of the right lateral ventricle.
Figure 1: Axial CT scan showing deep sulcus in the right frontal lobe.
Figure 2A: Axial T2-weighted MR showing deep sulcus in the right frontal lobe.
Figure 2B: Axial T2-weighted MR image.
Figure 3A: Coronal T2-weighted MR image.
Figure 3B: Coronal T1-weighted MR image showing heterotopic gray matter extending to the right frontal horn.
Diagnosis: Cortical dysplasia
Discussion: Focal cortical dysplasia is caused by abnormal neuroglial proliferation and organization. It is a primary differential consideration in focal drug refractory epilepsy. MR is useful in detecting these dysplasias which can appear as sulcogyral abnormalities, cortical thickening, blurring of the gray-white matter junction or a hyperintense signal within the dysplastic lesion and its underlying white matter.
"Bottom-of-sulcus dysplasia" has recently been added as a subtype of focal cortical dysplasia. MR revealed that small dysplastic lesions are often located at the base of a sulcus and that this sulcus is usually deeper than those in healthy control patients.
Surgical treatments for drug resistant epilepsy due to focal cortical dysplasia has resulted in seizure free rates of 40 to 86%. This is not only successful in the short term but remains constant after long term follow up. In one study however, being seizure free did not result in a significant improvement in employment status or daily living activities, such as the ability to drive.
References:
Besson P, Andermann F, Dubeau F, Bernasconi A. Small focal cortical dysplasia lesions are located at the bottom of a deep sulcus. Brain 2008. Dec; 131(Pt 12):3246-55.
PMID: 18812443 [PubMed]
Kral T, von Lehe M, Podlogar M, et al. Focal cortical dysplasia: long term seizure outcome after surgical treatment. J Neurol Neurosurg Psychiatry. 2007 Aug;78(8):853-6. PMID: 17287239 [PubMed]
Tassi L, Colombo N, Garbelli R, et al. Focal cortical dysplasia: neuropathological subtypes, EEG, neuroimaging and surgical outcome. Brain. 2002 Aug;125(Pt 8):1719-32. PMID: 12135964 [PubMed]
