Atypical Histopathological Findings in an Epilepsy Surgery Case of Sturge–Weber Syndrome With Coexisting Developmental Venous Anomaly

Leptomeningeal angiomatosis (LMA) in Sturge-Weber syndrome (SWS) typically presents with cortical calcifications on computed tomography (CT) scans and is often accompanied by enlarged, low-signal deep medullary veins seen on susceptibility-weighted magnetic resonance imaging (MRI) that lack flow-void signs on T2-weighted MRI. However, subcortical calcifications on CT and concurrent developmental venous anomaly (DVA), visible as deep medullary veins with prominent flow-void signs on T2-weighted MRI, are uncommon. We describe atypical clinicopathological features in a surgical case of a 6-year-old female patient with SWS, who had early-onset intractable epilepsy due to LMA, complicated by subcortical calcifications and DVA on neuroimaging. Presurgical MRI revealed a hypoplastic left frontal lobe covered with an LMA, and a DVA extending from the ipsilateral frontal periventricular white matter to the deep middle cerebral vein. She underwent resection of the left central and prefrontal regions and remained seizure-free postoperatively. Histopathology confirmed the presence of an LMA, dilated veins in the subcortical white matter, focal microscopic polymicrogyria, and cortical pseudolaminar sclerosis consistent with focal cortical dysplasia type IIIc. Four atypical findings were observed: (1) absent or minimal cortical calcifications; (2) clearly defined areas of fibrillary gliosis bordered by a linear band of prominent calcifications, encasing non-dilated veins in the subcortical white matter; (3) a localized cortical venous malformation; and (4) subarachnoid arterial abnormalities, including fibromuscular intimal thickening, internal elastic lamina degeneration, irregular medial thickness, and segmental medial losses replaced by dense calcifications. These findings, considered in the context of the intrinsic cerebral venous system, suggest that the non-dilated white matter veins encased by calcified gliosis represent superficial medullary veins, while the dilated veins correspond with deep medullary veins draining into the DVA. The latter possibly serve as collateral venous drainage pathways, compensating for abnormal cortical and subarachnoid venous development. The observed arterial abnormalities likely reflect secondary regressive changes.