Giant, lamellated colloid cyst: 'Russian-Doll' appearance.

Colloid cysts (CCs) are usually small, benign lesions located at the foramen of Monro. They usually grow to a size of 1-3 cms. We have described here a giant colloid cyst of size 6 x 5.2 x 4.4 cm with a unique radiological appearance of multiple concentric layers with different intensities which has not been described before. This unusual appearance is most probably due to the variation of hydration between the different layers with gradually decreasing concentration of protein from centre to periphery, which correlated well with intraoperative and histopathological findings.

Yield of video electro encephalography for phase 1 pre-surgical evaluation of drug resistant epilepsy in 1200 adults: retrospective study from a tertiary center situated in a lower-middle-income country.

INTRODUCTION: Video Electroencephalography (VEEG) is crucial for presurgical evaluation of Drug Refractory Epilepsy (DRE). The yield of VEEG in large volume centers, particularly those situated in Low-and Middle-Income countries (LMIC) is not well studied. METHODOLOGY: We studied 1200 adults with drug resistant focal epilepsy whose seizures were recorded during VEEG in the epilepsy monitoring unit. VEEG review and analysis was done independently by trained epileptologists. Video EEG and MRI data were examined for concordance in order to generate a hypothesis for the presumed epileptogenic zone. RESULTS: Analysis of seizure semiology provided information on the symptomatogenic zone in most cases except for 33 (2.75%) patients. A total of 1050 (87.5%) patients showed interictal epileptiform discharges (IEDs) with most (58.3%) showing unilateral IEDs. Most patients (n = 1162, 96.83%) showed ictal EEG discharges of which 951(81.8%) had unilateral ictal onset. Abnormal MRI was seen in 978 (81.5%) patients. Concordance of electroclinical data obtained by analysis of VEEG with MRI abnormality could be established in most patients (63%). Concordance was higher for patients with ictal onset from temporal regions (83.71%) as compared to posterior cortex (55.4%) and frontal regions (43.5%.) CONCLUSION: This study highlights the high yield of VEEG in phase 1 presurgical evaluation in DRE. Systematic evaluation of data from VEEG provided lateralizing and localizing information in most cases. Concordance between VEEG and MRI findings was noted in most patients. These findings support steps to increase referral for pre-surgical evaluation in DRE.

Exploring immunoreactivity of TTF-1 and AVP in hypothalamic hamartoma.

INTRODUCTION: Hypothalamic hamartoma (HH) is a rare developmental disorder presenting with gelastic seizures or precocious puberty attributed to gonadotrophin-releasing hormone expression by the hamartoma. The histogenesis of HH is uncertain, and diagnosis of HH is difficult in small biopsies due to its close resemblance to normal hypothalamic nuclei. TTF-1 and arginine vasopressin (AVP) are associated with gonadotropin-releasing hormone release. MATERIALS AND METHODS: In this study, we explored the expression pattern of TTF-1 and AVP in HH and its utility, if any, in diagnosis. We reviewed the clinical, radiologic, and histopathological features of 23 HH diagnosed over the past decade at our Institute. RESULTS: The age at presentation ranged from 11 months to 34 years with gelastic seizures (82.6%), precocious puberty (17.4%), and developmental delay (8.7%) as presenting symptoms. On imaging, all the lesions (n = 9) involved the posterior and tuberal group of hypothalamic nuclei, while 5 cases involved the anterior hypothalamus. Anatomically, the lesions involved mammillary body, arcuate and periventricular nuclei. On histopathology, 52% cases revealed nodular arrangement of small neurocytic cells separated by glial stroma. TTF-1 and AVP immunoreactivity was absent in all the cases, whereas in normal hypothalamus, AVP was expressed in periventricular nuclei. CONCLUSION: Our results suggest that immunoexpression of TTF-1 is absent in HH, particularly in those arising from the posterior hypothalamus, and this can be used in small biopsies to distinguish from a normal hypothalamus as well as from posterior pituitary tumors.

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.

Sleep profile and Polysomnography in patients with drug-resistant temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) and the effect of epilepsy surgery on sleep-a prospective cohort study.

OBJECTIVES: We analyzed changes in sleep profile and architecture of patients with drug-resistant TLE-HS using three validated sleep questionnaires- Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), NIMHANS Comprehensive Sleep Disorders, and polysomnography (PSG). We studied the effect of epilepsy surgery in a subset of patients. METHODS: In this prospective observational cohort study, sleep profile of 40 patients with drug-resistant TLE-HS was compared to 40 healthy matched controls. Sleep architecture of 22 patients was studied by overnight PSG and compared to 22 matched controls. Sleep profile was reassessed in 20 patients after a minimum period of three months after epilepsy surgery. RESULTS: The mean PSQI was higher among patients compared to controls(P=0.0004) while mean ESS showed no difference. NCSDQ showed fewer patients feeling refreshed after a night's sleep compared to controls (p=0.006). PSG revealed a higher time in bed (p=0.0001), longer total sleep time (p=0.006) and more time spent in NREM stage 1 (p=0.001) and stage 2 (p=0.005) while spending less time in stage 3 (p=0.039) among TLE patients. Sleep efficiency was worse in patients on ≥3 ASMs compared to those on 2 ASMs (p-0.044). There was no change in mean ESS (p=0.48) or PSQI (p=0.105) after surgery. CONCLUSIONS: Patients with drug-resistant TLE-HS have an altered sleep profile and architecture. Patients on ≥3 ASMs have a lower sleep efficiency. Reassessment at short intervals after epilepsy surgery did not reveal significant changes in sleep profile.

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.

Surgical Management and Outcomes of Aneurysms of Posterior Inferior Cerebellar Artery: Location-Based Approaches with Review of Literature.

Background Posterior inferior cerebellar artery (PICA) is a tortuous, variable, and uncommon site for aneurysms. Surgical management of PICA aneurysms involves careful selection of approach based on the location of the aneurysm and meticulous dissection of the neurovascular structures and perforators. Materials and Methods We did a retrospective review of all the PICA aneurysms operated at our institute in the past 10 years along with the site, presentation, and approach used for the same. Preoperative World Federation of Neurosurgical Society scores and follow-up modified Rankin scores (mRS) were also evaluated. During the same period, data for intervention cases of PICA aneurysm were also collected with follow-ups for a comparative analysis. Results A total of 20 patients with 21 PICA aneurysms were reviewed. All the reviewed cases presented with subarachnoid hemorrhage, and the most common location was the lateral medullary segment and vertebral artery (VA)-PICA junction. Midline approaches were used for distal PICA cases, with far-lateral approach reserved for anterior medullary/VA-PICA junction. No lower cranial nerve palsies were recorded at follow-up. Four cases needed cerebrospinal fluid diversion and two developed cerebellar infarcts. All cases were mRS 0 to 2 at follow-up. Conclusion Our series compares well with some of the larger surgical series of PICA aneurysms. This may be due to early referral patterns and early surgery (<24 hours) policy at our institution. Anatomical knowledge of PICA anatomy and sound perioperative management are keys to good outcomes in these cases.

Magnetoencephalography imaging of high frequency oscillations strengthens presurgical localization and outcome prediction.

In patients with medically refractory epilepsy, resective surgery is the mainstay of therapy to achieve seizure freedom. However, ∼20-50% of cases have intractable seizures post-surgery due to the imprecise determination of epileptogenic zone. Recent intracranial studies suggest that high frequency oscillations between 80 and 200 Hz could serve as one of the consistent epileptogenicity biomarkers for localization of the epileptogenic zone. However, these high frequency oscillations are not adopted in the clinical setting because of difficult non-invasive detection. Here, we investigated non-invasive detection and localization of high frequency oscillations and its clinical utility in accurate pre-surgical assessment and post-surgical outcome prediction. We prospectively recruited 52 patients with medically refractory epilepsy who underwent standard pre-surgical workup including magnetoencephalography (MEG) followed by resective surgery after determination of the epileptogenic zone. The post-surgical outcome was assessed after 22.14 ± 10.05 months. Interictal epileptic spikes were expertly identified, and interictal epileptic oscillations across the neural activity frequency spectrum from 8 to 200 Hz were localized using adaptive spatial filtering methods. Localization results were compared with epileptogenic zone and resected cortex for congruence assessment and validated against the clinical outcome. The concordance rate of high frequency oscillations sources (80-200 Hz) with the presumed epileptogenic zone and the resected cortex were 75.0% and 78.8%, respectively, which is superior to that of other frequency bands and standard dipole fitting methods. High frequency oscillation sources corresponding with the resected cortex, had the best sensitivity of 78.0%, positive predictive value of 100% and an accuracy of 78.84% to predict the patient's surgical outcome, among all other frequency bands. If high frequency oscillation sources were spatially congruent with resected cortex, patients had an odds ratio of 5.67 and 82.4% probability of achieving a favourable surgical outcome. If high frequency oscillations sources were discordant with the epileptogenic zone or resection area, patient has an odds ratio of 0.18 and only 14.3% probability of achieving good outcome, and mostly tended to have an unfavourable outcome (χ2 = 5.22; P = 0.02; φ = -0.317). In receiver operating characteristic curve analyses, only sources of high-frequency oscillations demonstrated the best sensitivity and specificity profile in determining the patient's surgical outcome with area under the curve of 0.76, whereas other frequency bands indicate a poor predictive performance. Our study is the first non-invasive study to detect high frequency oscillations, address the efficacy of high frequency oscillations over the different neural oscillatory frequencies, localize them and clinically validate them with the post-surgical outcome in patients with medically refractory epilepsy. The evidence presented in the current study supports the fact that HFOs might significantly improve the presurgical assessment, and post-surgical outcome prediction, where it could widely be used in a clinical setting as a non-invasive biomarker.

Role of intraoperative dynamic magnetic resonance myelogram in management of giant dorsolumbar spinal extradural arachnoid cyst: case report.

Giant dorsolumbar spinal arachnoid cysts are a complex, poorly understood, and difficult to manage clinical entity. Traditional CT myelography is technically difficult to use in these cases to detect the site of leakage preoperatively. The authors report a novel technique for detecting the site of the leak by using sequential, dynamic intraoperative MR myelography. To the authors' knowledge, there is no other similar report in the literature.