Arita, Kazunori

Background: Intrasellar kissing carotid arteries are a rare variant in which bilateral internal carotid arteries run very near each other at their cavernous sinus portion. We encountered a woman with the pituitary gland mimicking a pituitary microadenoma because the pituitary gland was compressed bilaterally by intrasellar kissing carotid arteries. Case Description: A 61-year-old woman with a chronic headache underwent magnetic resonance imaging, which revealed a sellar mass measuring 10.2 mm in height, 8.2 mm in length, and 4.0 mm in width at the midintercarotid level. Blood levels of all pituitary and target-organ hormones were within normal range. The height and superior convex shape of the sellar mass suggested that it was a nonfunctioning microadenoma, which was monitored over the past 16 years. A recent three-dimensional reconstruction of magnetic resonance angiography clearly showed that the pituitary gland was squeezed upward, compressed bilaterally, and extended superiorly by intrasellar kissing carotid arteries. Conclusion: The pituitary gland can be squeezed upward by intrasellar kissing carotid arteries and mimic pituitary tumor.

Background: Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder presenting a triad including dementia and ventricular enlargement. The mechanism causing excessive cerebrospinal fluid (CSF) accumulation in the ventricles in iNPH is poorly understood. We hypothesized that the age-related degradation of the spinal shock-absorbing system composed of a spinal dural sac (SDS) and surrounding soft tissue, preventing ventricular enlargement caused by wide CSF pulsation driven by heartbeats, may be involved in the ventricular enlargement observed in iNPH. Methods: Sixty-four patients with iNPH in their seventies who underwent a lumboperitoneal shunt and a control group of 79 people in the same age group who underwent brain check-ups were included in the study. We compared the sizes of the cervical and upper parts of the thoracic SDS using magnetic resonance imaging between the two groups. Results: The anterior-posterior distances of the dural sac at C5 were shorter in patients with iNPH of both sexes than those in the control group (P = 0.0008 in men and P = 0.0047 in women). The number of disc levels with disappeared CSF space surrounding the cervical cord was more in iNPH (P = 0.0176 and P = 0.0003). The midsagittal area of the upper part of the spinal sac, C2-Th4, was smaller in iNPH (P = 0.0057 and P = 0.0290). Conclusion: Narrowing of the cervical dural sac and midsagittal area in the upper part of the SDS in patients with iNPH may reflect the degradation of the shock-absorbing mechanism for CSF pressure pulsations, which may cause iNPH or at least aggravate iNPH by other unknown causes.

Background:We previously found the usefulness of dural sac shrinkage signs (DSSSs), which are the anterior shift of the spinal cord and dura mater behind the cord, detected by magnetic resonance imaging (MRI) at the thoracic level for the diagnosis of spontaneous intracranial hypotension (IH). This is a retrospective survey on the usefulness of DSSSs for the early detection of iatrogenic IH caused by overdrainage through a lumboperitoneal shunt (LPS) for patients with idiopathic normal pressure hydrocephalus (INPH).Methods:Forty-five INPH patients had an LPS using a pressure programmable valve equipped with an anti-siphon device.Results:Nine patients complained of orthostatic headache after the LPS, indicating IH due to overdrainage, which persisted for more than a week in three patients and 2–7days in six patients. The headache was transient/ nonorthostatic in ten patients and absent in 26 patients. The DSSSs and accompanying enlargement of the venous plexus were observed in all three patients with prolonged orthostatic headaches. Only the anterior shift of the dura mater was observed in 1 (4%) among 25 patients who had short-term orthostatic headache, transient/ nonorthostatic headache, or absent headache, and underwent spinal MRI. A patient with prolonged severe orthostatic headache with both DSSSs eventually developed intracranial subdural effusion and underwent tandem valve surgery, which provided a quick improvement of symptoms. The DSSSs on thoracic MRI also disappeared promptly.Conclusion:DSSSs may serve as objective signs for the diagnosis of IH due to overdrainage through an LPS for INPH.

Background: Giant perivascular spaces (PVSs) are very rare condition in the brain and can be associated with neurological symptoms. It often enlarges and causes obstructive hydrocephalus which requires surgical intervention. However, the growth velocity has never been investigated. Case Description: Here, we report a woman in her early eighties with giant PVSs eventually followed up 17 years. She presented with dizziness and mild headache for a week and her neurological examination showed no abnormality. Her brain magnetic resonance imaging (MRI) showed a multiple cystic lesion, 28 mm in maximum diameter as a whole, in the left mesencephalothalamic region. There were no solid part, rim enhancement, or perilesional intensity change suggesting edema or gliosis. Smaller PVSs were also seen in bilateral-hippocampi, basal ganglia, white matter, and left frontal operculum. Retrospectively, five MRI studies over 17 years were analyzed using a 3-D volumetric software and found a very slow growth of the lesion, from 6.54 ml to 9.83 ml indicating gain of 0.1752 ml (2.68%) per year. Conclusion: This is the first report verifying a gradual enlargement of giant PVSs in a natural course. The prospective 3-D volumetric analysis on PVSs may elucidate the true nature of these lesions.

Background: Accurate diagnosis of brain tumor is crucial for adequate surgical strategy. Our institution follows a comprehensive preoperative evaluation based on clinical and imaging information. Methods: To assess the precision of preoperative diagnosis, we compared the “top three list” of differential diagnosis (the first, second, and third diagnoses according to the WHO 2007 classification including grading) of 1061 brain tumors, prospectively and consecutively registered in preoperative case conferences from 2010 to the end of 2017, with postoperative pathology reports. Results: The correct diagnosis rate (sensitivity) of the first diagnosis was 75.8% in total. The sensitivity of the first diagnosis was high (84–94%) in hypothalamic-pituitary and extra-axial tumors, 67–75% in intra-axial tumors, and relatively low (29–42%) in intraventricular and pineal region tumors. Among major three intra-axial tumors, the sensitivity was highest in brain metastasis: 83.8% followed by malignant lymphoma: 81.4% and glioblastoma multiforme: 73.1%. Sensitivity was generally low (≦60%) in other gliomas. These sensitivities generally improved when the second and third diagnoses were included; 86.3% in total. Positive predictive value (PPV) was 76.9% in total. All the three preoperative diagnoses were incorrect in 3.4% (36/1061) of cases even when broader brain tumor classification was applied. Conclusion: Our institutional experience on precision of preoperative diagnosis appeared around 75% of sensitivity and PPV for brain tumor. Sensitivity improved by 10% when the second and third diagnoses were included. Neurosurgeons should be aware of these features of precision in preoperative differential diagnosis of a brain tumor for better surgical strategy and to adequately inform the patients.

Atypical teratoid/rhabdoid tumor (ATRT) is a highly malignant brain tumor predominantly encountered in infants. Mutations of the SMARCB1 gene are the characteristic genetic lesion. A small group of ATRT stands out clinically, because these tumors are located in the sellar region of adults. To investigate if sellar region ATRT in adults represents a molecular distinct entity, we characterized molecular alterations in 7 sellar region ATRTs in adults as compared with 150 pediatric ATRTs and 47 pituitary adenomas using SMARCB1 sequencing, multiplex ligation-dependent probe amplification and fluorescence in situ hybridization as well as DNA methylation profiling. The median age of the 6 female and 1 male patients was 56 years. On histopathologic examination, all tumors were malignant rhabdoid tumors showing loss of SMARCB1/INI1 protein expression. Two cases displayed compound heterozygous SMARCB1 point mutations, 3 cases showed heterozygous SMARCB1 deletions with point mutations of the other allele and 1 case a homozygous SMARCB1 deletion; in 1 case, underlying SMARCB1 alterations could not be identified. On unsupervised hierarchical cluster analysis of DNA methylation profiles, sellar region ATRTs did not form a distinct group, but clustered with ATRT-MYC, 1 of 3 recently described molecular subgroups of ATRT. On analysis of DNA methylation array intensity data, only 1 sellar region ATRT showed characteristic features of pediatric ATRT-MYC, that is, major copy number losses affecting the SMARCB1 region. In conclusion, these results suggest that sellar region ATRTs in adults form a clinically distinct entity with a different mutational spectrum, but epigenetic similarities with pediatric ATRTs of the ATRT-MYC subgroup.