Focal cortical dysplasia: type IIb

Case contributed by RMH Neuropathology


Frontal lobe epilepsy.

Patient Data

Age: 33
Gender: Male

MRI Brain (3T)

An abnormality in the right pars opercularis consists of a subcortical triangular region of the increased FLAIR signal, isointense to cortex with a band of signal abnormality extending centrally toward the right frontal horn. There is blurring of the overlying cortex. Although most conspicuous on the DIR sequences, this region of abnormality can also be appreciated on T1 and T2-weighted imaging. Appearance is consistent with focal cortical dysplasia (Taylor's).

No further abnormality identified. No diffusion restriction or susceptibility artefact. Within the limits of a non-dedicated study, the mesial temporal lobes, including the hippocampi, are unremarkable in size, signal and morphology.

Conclusion: Focal cortical dysplasia in the right frontal lobe pars opercularis.


MICROSCOPIC DESCRIPTION: The sections include cerebral cortex and white matter. The neurons in the cortex are focally disorganized and show crowding. The lamination pattern of the cortical layers is distorted. The cytoplasmic processes run in different directions. The neurons show nuclear enlargement with prominent nucleoli. Some bi or multinucleated forms are seen. The Nissl substance in the cytoplasm shows clumping. There are scattered balloon cells with abundant eosinophilic cytoplasm. Increased numbers of neurons are present in the white matter. They do not form a discrete mass. The adjacent astrocytes show reactive gliosis. No evidence of malignancy is identified. IDH-1 immunostain is negative. The topoisomerase index is less than 1%. The features are those of focal cortical dysplasia (ILAE type IIb).

DIAGNOSIS: Brain tissue: Focal cortical dysplasia (ILAE type IIb). 

Case Discussion

Focal cortical dysplasias represent a heterogeneous group of disorders of cortical formation, which may demonstrate both architectural and proliferative features. They are one of the most common causes of epilepsy and can be associated with hippocampal sclerosis and cortical glioneuronal neoplasms. 

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Case information

rID: 38527
Published: 23rd Jul 2015
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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