Altered vascular permeability but not angiogenesis may play a role in the epileptogenesis of human hippocampal sclerosis.

OBJECTIVE: We investigated the role of angiogenesis and vascular permeability in the pathogenesis of human drug-resistant epilepsy due to hippocampal sclerosis. METHODS: Resected hippocampi from 30 histologically confirmed cases of hippocampal sclerosis and 30 age-matched post-mortem controls were examined by immunohistochemical quantitation of vascular endothelial markers, CD31 and CD105 (markers of newly formed vessels), and data were analysed relative to MR volumetry. The blood-brain barrier was evaluated based on immunohistochemistry for IgG, albumin, VEGF and AQP4. RESULTS: Mean vascular density in the hippocampus was 8.71/mm2 in hippocampal sclerosis samples compared to 7.94/mm2 in age-matched controls. No statistically significant increase in vascular density was found in hippocampal sclerosis samples. Although no neoangiogenesis was found in hippocampal sclerosis samples based on CD105, breakdown of the blood-brain barrier, enhanced neuronal expression of VEGF, and perivascular seepage of IgG and albumin with uptake within neurons and astrocytes were found. Redistribution of the water channel protein, AQP4, reflected by change from normal punctate labelling to intense diffuse staining in hippocampal sclerosis samples, indicated an altered glia-vascular interface, disrupting blood-brain barrier permeability. SIGNIFICANCE: Our data show no objective histological evidence of angiogenesis in hippocampal sclerosis samples. When controlled for the confounding variable of hippocampal area, there was no difference in vascular density between cases and controls. A leaky blood-brain barrier and redistribution of AQP4 were identified which may contribute to epileptogenesis. This constitutes the largest study in the published literature evaluating a role of vascular permeability and angiogenesis in human hippocampal sclerosis.

Dual/double pathology in neurocysticercosis causing drug resistant epilepsy - Chance association or causal?

INTRODUCTION: Neurocysticercosis (NCC) as cause of drug resistant epilepsy (DRE) is commonly reported from India. We reviewed the neuropathological findings in patients undergoing resective surgery for DRE due to NCC, to determine the pathomechanism of epileptogenesis. METHODS: Clinical, demographic and neuropathological findings of histologically confirmed cases of NCC causing DRE between 2005-2019 were reviewed. NeuN, GFAP, phosphorylated neurofilament, vimentin, CD34 for glial/ neuronal alterations, and Masson trichrome, Luxol Fast blue for evidence of fibrosis/ demyelination was used to determine cause of epileptogenesis. RESULTS: There were 12 cases of NCC associated with dual/ double pathology, which constituted 3.02 % (12/398) of all the operated DRE. [Age range: 17-37y, Male:Female = 1.4:1]. Seizure duration ranged from 3-32y, with seizure onset between 4-27y. On MRI, lesions were of variable signal intensity on T1 and isointense on T2 with blooming on GRE/ SWI, and CT revealed calcification. Majority (11/12) had associated hippocampal sclerosis (HS) type 1 (dual pathology), localised to the same side as cysticercal cyst, suggesting it may be involved in the pathogenesis of HS. Ten had single cysticercal lesion involving ipsilateral hippocampus in 6, parahippocampal gyrus in 2, amygdala and temporal lobe in 1 case each. One had multiple NCC located in bilateral frontal, parietal and ipsilateral hippocampus. Adjacent cortex around the NCC evaluated in 6 cases, revealed inflammation, gliosis, axonal disruption/ beading, and variable synaptic/ neuronal dystrophic changes. There was a single case of NCC with Focal cortical dysplasia (FCD) type IIb (double pathology). In 11/12 cases Engel's post-surgery outcome was available with all having class I outcome. CONCLUSION: HS was most common pathology associated with cysticercosis (Dual pathology), localised ipsilateral to the cysticercal cyst, suggesting that HS is a secondary/ epiphenomenon. Perilesional changes such as inflammation, gliosis, dystrophic synaptic and axonal pathology play a role in inducing or perpetuating the epileptiform activity. The association of FCD IIb with NCC in one case is likely to be a chance occurrence.

Ocular pathology in NeuroAIDS - An autopsy study.

The central nervous system (CNS) and the eye are involved in Human immunodeficiency virus related disease. Although, optic nerve is considered an extension of the CNS, it has not been systematically evaluated to determine if infections of brain can extend into the eye or vice versa. The brain and posterior compartment of eyeball retrieved at autopsy of patients succumbing to NeuroAIDS, were evaluated with Hematoxylin & Eosin, special stains and immunohistochemistry for infective pathogens. Multiplex PCR was performed in vitreous, CSF and serum for simultaneous detection of bacterial, viral, and protozoal opportunistic infections. Ocular involvement in NeuroAIDS was seen in 93.7% (15/16) with opportunistic infection being the most common 62.5% (10/16); with toxoplasma optic neuropathy in 5 (50%), Cryptococcal optic neuritis in 3 (30%), and Cytomegalovirus chorioretinitis in 2 (20%). Concordance between ocular and CNS pathology was seen in 50% of cases. CSF PCR was more sensitive than PCR in vitreous for detecting ocular infections in posterior compartment of eye.

Rare occurrence of gangliocytoma in the medulla oblongata.

Gangliocytoma is an uncommon low-grade neuroepithelial tumour arising in the cerebral hemispheres, with medulla oblongata being extremely rare site of occurrence. We report a case of an 8-year-old female with recurrent vomiting, hypertension and left hemifacial spasms with a dorsally exophytic lesion arising from the medulla projecting into the fourth ventricle. She underwent excision of the lesion with intra operative cranial nerve monitoring guidance. Histopathology revealed clusters of large mature ganglion cells which were labelled by synaptophysin and CD34. Extreme rarity in this location makes clinical diagnosis and management of gangliocytoma challenging, although prompt diagnosis and total excision has a successful outcome. There are only six previous reports of gangliocytoma in the medulla oblongata.

Unusual occurrence of supratentorial medulloepithelioma in a young female.

Medulloepithelioma is an extremely rare PNET in late adolescence and adults with only two cases noted in literature. These are WHO grade IV tumors with dismal prognosis. Only few cases survived beyond 5 months. We report a rare case of supratentorial medulloepithelioma in a 17 year old girl. She had presented with right sided weakness, headache and vomiting. Imaging showed an enhancing mass lesion in left parietal region which undergone gross total resection. After surgery, her headache, vomiting and right sided weakness improved. On histopathology, the tumor had characteristic trabecular, ribbon and palisaded arrangement with brisk mitotic activity, necrosis and calcification. Immuno-histochemistry revealed positivity for Synaptophysin, Vimentin and EMA while GFAP was negative. MIB-1 labeling was very high. Patient received postoperative radiotherapy. On follow up after 14 months, she was clinically asymptomatic with no recurrence on imaging.