Intrasellar Arachnoid Cyst, a Rare Radiological Finding: Report of a Case.

Intrasellar arachnoid cysts are uncommon radiological findings, generally incidental and clinically silent. We present the case of 70 year-old female who was treated of meningitis due to cerebrospinal fluid nasal fistulae. She was diagnosed of intrasellar arachnoid cyst and managed conservatively because no neurologic, hormonal, symptomatic either CSF fistulae appeared during follow-up. The origin of intrasellar arachnoid cysts is unclear; although an incomplete diaphragma sellae through basal arachnoid membrane herniates may be a plausible theory. Conservative treatment is the usual option, but if hormonal, visual or intracranial hypertension symptoms appeared, surgery may be the best therapy. This entity should be in the differential diagnosis of cystic sellar lesions with other benign cysts and tumors as craniopharyngioma.

Arachnoid membrane as a source of sphingosine-1-phosphate that regulates mouse middle cerebral artery tone

Growing evidence indicates that perivascular tissue is critical to modulate vessel function. We hypothesized that the arachnoid membrane surrounding middle cerebral artery (MCA) regulates its function via sphingosine-1-phosphate (S1P)-induced vasoconstriction. The MCA from 3- to 9-month-old male and female wild-type (Oncine France 1 and C57BL/6) mice and sphingosine kinase 2 knockout (SphK2-/-) mice in the C57BL/6 background was mounted in pressure myographs with and without arachnoid membrane. Raman microspectroscopy and imaging were used for in situ detection of S1P. The presence of arachnoid tissue was associated with reduced external and lumen MCA diameters, and with an increase in basal tone regardless of sex and strain background. Strong S1P-positive signals were detected in the arachnoid surrounding the MCA wall in both mice models, as well as in a human post-mortem specimen. Selective S1P receptor 3 antagonist TY 52156 markedly reduced both MCA vasoconstriction induced by exogenous S1P and arachnoid-dependent basal tone increase. Compared to 3-month-old mice, the arachnoid-mediated contractile influence persisted in 9-month-old mice despite a decline in arachnoid S1P deposits. Genetic deletion of SphK2 decreased arachnoid S1P content and vasoconstriction. This is the first experimental evidence that arachnoid membrane regulates the MCA tone mediated by S1P.

Postsurgical Size-Changing Temporal Lobe Arachnoid Cysts in Patients with Trigonocephaly Who Underwent Reconstructive Surgery: A Two-Case Report

<b><i>Introduction:</i></b> Trigonocephaly (TC), the tapering of the metopic suture toward the anterior, lateral inadequacy of supraorbital bar, hypoplasia of the ethmoid bone, and hypotelorism due to orbital medialization leads to a triangular shape in the head together with frontotemporal stenosis and widening of the biparietal diameter. Arachnoid cysts (ACs) are benign cysts, which are formed by cerebrospinal-fluid entrapment into the arachnoid membrane due to duplication or separation of the arachnoid membrane layers. ACs are typically located in the middle cranial fossa and Sylvian fissure region. They are mostly detected incidentally through neuroimaging. The coexistence of TC and AC is considerably rare; hence, its actual incidence is unknown. To our knowledge, the coexistence of nonsyndromic TC and AC has been revealed in only 2 publications in the literature. In this case study, 2 patients, one of whom were with unilateral and the other with bilateral temporally localized ACs, sizes of which increased following the reconstructive surgeries, and who underwent reconstructive surgery for TC, were presented. <b><i>Case Report:</i></b> Both of the 2 patients that we have presented in our study are 7 months old and male. Fronto-orbital advancement and calvarial remodeling operations were performed on both. ACs of the patients were not intervened. However, in the post-op follow-ups, the left temporal cyst of the 1st case and the right cyst of the 2nd case grew radiologically, and the left cyst became very small. <b><i>Discussion/Conclusion:</i></b> TC must be treated surgically. ACs may show changes in size secondary to the increase in intracranial volume following reconstructive surgery for TC. However, if it does not give rise to any complaints, it can be followed-up clinically and radiologically. Patients should be followed-up for many years, given that neurodevelopmental and behavioral problems may occur later in both pathologies.

Aging-associated inflammation and fibrosis in arachnoid membrane

Background The physiological and pathological significance of the arachnoid membrane (AM) is still unknown. In this study, we investigated various characteristics of the AM, focusing on the influence of inflammation and fibrosis. Methods Small pieces of AM sample were obtained during neurosurgical procedures from 74 cases. The clinical and pathological characteristics of the hyperplastic AM group (≥ 50 μm) and the non-hyperplastic AM group (< 50 μm) were compared. Then, potential correlations between AM thickness and clinical characteristics were analyzed. Moreover, VEGFα, TGFβ, and TGFα levels were quantitated by real time PCR. Then, the potential correlations between AM thickness and these inflammatory or anti-inflammatory markers, and the influence of the original disease were calculated. Results The median age of the patients in hyperplastic AM group was significantly older than that of the non-hyperplastic AM group. Moreover, the number of fibroblasts, CD68+ cells, CD86+ cells, and CD206+ cells in the hyperplastic AM group was significantly higher than that in the non-hyperplastic AM group. The AM thickness was significantly correlated to age and number of fibroblasts, CD68+ cells, CD86+ cells, and CD206+ cells. The thickness of the AM was significantly correlated to the messenger RNA expression levels of VEGFα (ρ = 0.337), and the VEGFα expression levels were significantly correlated with TGFβ and TNFα. Conclusions The AM hyperplasia was influenced by aging and could be a result of inflammation and fibrosis through cytokine secretion from the inflammatory cells and fibroblasts in the AM.

Aging-associated inflammation and fibrosis in arachnoid membrane

Background The physiological and pathological significance of the arachnoid membrane (AM) is still unknown. In this study, we investigated various characteristics of the AM, focusing on the influence of inflammation and fibrosis. Methods Small pieces of AM sample were obtained during neurosurgical procedures from 74 cases. The clinical and pathological characteristics of the hyperplastic AM group (≥ 50 µm) and the non-hyperplastic AM group (< 50 µm) were compared. Then, potential correlations between AM thickness and clinical characteristics were analyzed. Moreover, VEGFα, TGFβ, and TGFα levels were quantitated by real time PCR. Then, the potential correlations between AM thickness and these inflammatory or anti-inflammatory markers, and the influence of the original disease were calculated. Results The median age of the patients in hyperplastic AM group was significantly older than that of the non-hyperplastic AM group. Moreover, the number of fibroblasts, CD68+ cells, CD86+ cells, and CD206+ cells in the hyperplastic AM group was significantly higher than that in the non-hyperplastic AM group. The AM thickness was significantly correlated to age and number of fibroblasts, CD68+ cells, CD86+ cells, and CD206+ cells. The thickness of the AM was significantly correlated to the messenger RNA expression levels of VEGFα (ρ = 0.337), and the VEGFα expression levels were significantly correlated with TGFβ, which in turn was significantly correlated with TNFα. Conclusions The AM hyperplasia was influenced by aging and could be a result of inflammation and fibrosis through cytokine secretion from the inflammatory cells and fibroblasts in the AM.

Endoscopic third ventriculostomy in children: problems and surgical outcome: analysis of 34 cases

Background Endoscopic third ventriculostomy (ETV) has been established as a viable treatment option for obstructive hydrocephalus of children over 6 weeks of age. ETV in pediatric groups may be unsuccessful due to the failure of absorption of cerebrospinal fluid (CSF) or reclosure of ventriculostomy stoma or due to infection. The exact cause is still debatable. Some issues like failure to eliminate the second membrane during the procedure or formation of the new arachnoid membrane at the stoma are still not clear. This study aims to assess the surgical failure of ETV and its predisposing factors. Methods Thirty-four pediatric patients with hydrocephalus were analyzed retrospectively. The patients’ age limit was between 2.5 months and 14 years. This is a retrospective study of 34 patients in a single private hospital between June 2012 and January 2018. Patients having hydrocephalus in pediatric groups more than 6 weeks of age were included in the study. Results The mean age of all patients was 51.25 ± 53.90 months and the mean follow-up period was 50.47 ± 20.84 months. Of 34 surgeries, the success rate was 79% and the failure rate was 21%. Within 2 years, the success rate was 68.42% and above 2 years’ success rate was 93.33%. In this series, 7 cases of ETV were re-explored and found ventriculostomy stoma closure in 3 cases, the presence of the second membrane in re-exploration 2 cases, and presence of inflammatory arachnoid membrane in re-exploration 2 cases. The use of dexamethasone around the stoma in inflammatory stoma was useful, having no recurrence. In one patient of the second membrane probably due to absorption failure in communicating hydrocephalus re-exploration was failed and was managed successfully with VP shunt. Conclusions Predisposing factors causing ETV failure are ventriculostomy stoma closure by new arachnoid granulation tissues, remnants of the second membrane inside the stoma, CSF absorption failure, infection/high protein in CSF and inappropriate patient selection.