Encephalomalacic dysplastic mass lesion associated with vascular abnormalities in an elderly man. Is this "acquired" focal cortical dysplasia?

Focal cortical dysplasia (FCD) is known to occur in association with a principal lesion and has been newly introduced as FCD type III in the ILAE 2011 classification system of FCDs. FCD type IIIc is associated with vascular malformations, and in all such cases in the literature with histologic confirmation, the principal lesion was a cavernous angioma. We present here a case of mass-forming FCD type IIIc with very unusual vasculopathies. The patient, a 75-year-old man, presented with a seizure and left-sided weakness. MRI showed a right frontal intra-axial mass (4 cm in diameter). He had significant multiple cardiovascular risk factors and a history of melanoma and bladder cancer. Craniotomy was performed for excision of the suspected neoplasm. Histologically, the cortex showed transition from normal, laminar cortical architecture to marked architectural abnormality with irregular areas of encephalomalacia, with intervening, almost nodular regions of "preserved" cortex. These regions consisted of large clusters of dysplastic and maloriented neurons. There were medium-sized to larger arteries with marked medial thickening and luminal stenosis, predominantly within the markedly thickened and fibrosed leptomeninges. In addition, the parenchymal vessels showed markedly hyalinized and thickened walls, and several exhibited glomeruloid clusters of new capillaries. We interpreted the cortical and subcortical encephalomalacic features to be presumably "secondary" to the underlying/associated vascular pathology. This case may represent "acquired" FCD. It is possible that this patient had a preexistent cortical dysplasia with secondary ischemic changes; however, given the absence of previous history of seizure, this appears less likely.