Naoyuki Ohe

Venous drainage patterns in perimesencephalic nonaneurysmal subarachnoid hemorrhage

OBJECTIVE The precise etiology of perimesencephalic nonaneurysmal subarachnoid hemorrhage (P-SAH) has not yet been determined. We decided to compare the venograms of patients with P-SAH with those of patients with aneurysmal SAH (A-SAH) to examine the relationship between P-SAH and venous drainage patterns. METHODS We retrospectively studied 18 patients with P-SAH during the past 10 years and 112 patients with ruptured A-SAH during the past 4 years by reevaluating their venograms for possible abnormalities in venous structures, particularly focusing on the basal vein of Rosenthal (BVR). Anatomical variants were classified into three types according to the drainage pathway. RESULTS The location and drainage pathway of the BVR proved to be a significantly more primitive configuration in patients with P-SAH than in those with A-SAH (P<0.05). On the other hand, physical action including components of the Valsalva maneuver were the cause of nine cases of P-SAH (69.2%) in this case profile. The occurrence rate was significantly higher in the P-SAH group than in the A-SAH group (14.3%) (p<0.05). CONCLUSION Our data suggest that failure of longitudinal anastomoses between the primary primitive veins as well as excessive strenuous exertion including components of the Valsalva maneuver plays an important predisposing role in the etiology of P-SAH.

Olig2 is useful in the differential diagnosis of oligodendrogliomas and extraventricular neurocytomas

A 42-year-old woman had suffered from headaches since April 2009. Computed tomography revealed a tumor with marked calcification in the left frontal lobe adjacent to the left anterior horn of the lateral ventricle. T1-weighted gadolinium-enhanced magnetic resonance imaging showed a well-enhanced tumor at the lesion. Dynamic methionine positron emission tomography showed no delayed methionine attenuation. Initial preoperative diagnosis was extraventricular neurocytoma (EVN). However, oligodendroglioma was determined upon a second diagnosis. The patient underwent total tumor removal. Hematoxylin and eosin staining showed the characteristic fried egg-like cells, round nuclei, and immunohistochemically, the tumor cells were positive for glial fibrillary acidic protein, synaptophysin, neuronal nuclear antigen, microtubule-associated protein 2 and Olig2. The MIB-1 labeling index was 20%, which suggested malignancy. Although these findings demonstrated that the tumor had glioneuronal character, it was difficult to differentiate between EVN and oligodendroglioma. There have been reports that Olig2 immunohistochemistry is generally positive in cases of oligodendroglioma, but not in cases of neurocytoma. We completed the diagnosis as oligodendroglioma. Subsequent electron microscopy results presented oligodendroglial but not neuronal characteristics. We concluded that Olig2 is useful in the differential diagnosis of oligodendrogliomas and EVNs.

Clinicopathological features from long-term observation of a papillary tumor of the pineal region (PTPR): a case report

Papillary tumor of the pineal region (PTPR) was recently added to the 2007 WHO classification of tumors of the central nervous system as a rare pineal tumor. We present a case of a 17-year-old man who developed a 3-cm pineal tumor that was incompletely excised following two operations. The pathological findings presented were extensive epithelial papillary structures surrounding vessels mimicking “perivascular pseudo-rosettes,” leading to a diagnosis of “papillary ependymoma.” Subsequently, the residual tumor recurred on three separate occasions. Immunohistochemical studies showed the tumor was positive for cytokeratin 18 (CK 18), microtubule-associated protein (MAP 2), neuron-specific enolase (NSE), neuronal nuclei (NeuN), and transthyretin, consistent with mature neuronal differentiation. Given these findings, the diagnosis of PTPR was made. The patient’s survival time of 218 months is the longest reported to date for this tumor.

Radiological response and histological changes in malignant astrocytic tumors after stereotactic radiosurgery

Stereotactic radiosurgery is an encouraging approach to deliver higher doses of radiation boost for malignant gliomas safely and precisely. The purpose of this study was to investigate the radiation response and histological changes of malignant astrocytic tumors after stereotactic linac radiosurgery (SLRS). We studied an autopsy case of recurrent glioblastoma multiforme (GBM) and two surgical cases with gross total removal of recurrent GBM and anaplastic astrocytoma transformed from fibrillary astrocytoma treated with SLRS. Destructive changes, such as the disappearance of viable cells, coagulation necrosis, and fibrinoid degeneration of vascular walls, were observed in the center of the target of SLRS, which showed histologically similar radiobiological reactions to well-known delayed central nervous system radiation necrosis caused by conventional radiotherapy. The region showing such radiation necrosis was within the area irradiated with approximately 15–20Gy or more by SLRS; however, dense viable tumor cells remained in the periphery that was irradiated with less than 15 Gy. In a comparative immunohistochemical study of the tumors before and after SLRS, neither MIB-1 and p53 labeling indices nor immunoreactivity for GFAP represented any persistent tendencies. There were very few TUNEL-positive cells in either tumor before and after SLRS. These results showed that radiosurgery for malignant gliomas leads to earlier radiation necrosis than conventional radiation and that it is useful in eradicating tumor cells in the center of the target. However, some viable tumor cells may remain in the periphery irradiated with an insufficient dose for cell death and may be partly transformed in character by DNA damage due to radiation. Proton magnetic resonance spectroscopy (MRS) was suggested to characterize the radiation response in radiosurgery tumor targets for correlation with histological findings.

Reversible cerebrospinal fluid edema and porencephalic cyst, a rare complication of ventricular catheter

Cerebrospinal fluid (CSF) edema and porencephaly are rare postoperative complications of a ventricular shunt that result from obstruction of the distal catheter, especially in children with taut ventricles. We report a 10-year-old male with cerebellar germinoma complicated by obstructive hydrocephalus. Ventriculopuncture was performed and an Ommaya reservoir was implanted at the right frontal horn. A distal catheter was initially attached to the reservoir for drainage of hydrocephalus but was later removed. After surgery, multi-agent chemotherapy and radiation therapy, a brain MRI showed CSF edema and porencephaly in the right frontal white matter. These lesions were reduced by prompt removal of the ventricular catheter. It is important to recognize such complications and to remove the catheter as soon as possible, because the brain tissue affected by massive edema may develop irreversible changes. Advanced MRI techniques, including fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging may be helpful for assessing this pathological condition and its prognosis.

Intraventricular glioneuronal tumor with disseminated lesions at diagnosis--a case report.

A 55-year-old man presented with a large tumor in his lateral ventricles. Magnetic resonance imaging revealed disseminated lesions in the third and fourth ventricles at the time of diagnosis. The patient underwent a partial removal of the tumor in the lateral ventricles. Histologically, the surgical specimens showed glioneuronal differentiation with ganglion or ganglioid cells, Rosenthal fibers, oligodendroglia-like honeycomb appearances, a spongy pattern, perivascular pseudorosettes, and many hyalinized blood vessels. Papillary structure was not observed. The neuronal component showed a moderately high labeling index of Ki-67/MIB-1. We diagnosed this tumor as atypical intraventricular glioneuronal tumor. The disseminated lesions disappeared after chemoradiation therapy with temozolomide, and the residual tumors in the lateral ventricles remained stable for 3 years after the surgery. We discuss the pathological diagnosis, therapy and clinical course with review of the literatures.

Changes in Protein Level in the Cerebrospinal Fluid of a Patient with Cerebral Radiation Necrosis Treated with Bevacizumab

A 32-year-old woman underwent surgeries and radiation therapy for astrocytoma. She developed symptomatic radiation necrosis in the lesion, which caused hydrocephalus. She initially underwent ventricular drainage, because the protein level in the cerebrospinal fluid (CSF) was 787 mg/dL, which was too high for shunt surgery. Because she also had breast cancer, which was pathologically diagnosed as an invasive ductal carcinoma, standard bevacizumab therapy in combination with paclitaxel every 2 weeks was selected. Interestingly, after 2 days, the agents had dramatically reduced the CSF protein level. However, it returned to approximately the initial level within 2 weeks. After two courses of this regimen, a ventriculoperitoneal shunt was placed. After 10 courses of this regimen, the CSF protein level decreased to 338 mg/dL, which is less than half of the initial level. Long-term administration of bevacizumab might decrease leakage of protein from the vessels around the ventriculus.

Efficacy, reliability, and safety of completely autologous fibrin glue in neurosurgical procedures: single center retrospective large number case study

OBJECTIVE Commercially available fibrin glue (Com-FG), which is used commonly worldwide, is produced with pooled human plasma from multiple donors. However, it has added bovine aprotinin, which involves the risk of infection, allogenic immunity, and allergic reactions. We evaluate the efficacy, reliability, and safety of completely autologous fibrin glue (CAFG). METHODS From August 2014 to February 2016, prospective data were collected and analyzed from 153 patients. CAFG was prepared with the CryoSeal System using autologous blood and was applied during neurosurgical procedures. Using CAFG-soaked oxidized regenerated cellulose and/or polyglycolic acid sheets, we performed a pinpoint hemostasis, transposed the offending vessels in a microvascular decompression, and covered the dural incision to prevent cerebrospinal fluid leakage. RESULTS The CryoSeal System had generated up to a mean of 4.51 mL (range, 3.0-8.4 mL) of CAFG from 400 mL autologous blood. Com-FG products were not used in our procedures. Only 6 patients required an additional allogeneic blood transfusion. The hemostatic effective rate was 96.1% (147 of 153 patients). Only 1 patient who received transsphenoidal surgery for a pituitary adenoma presented with the complication of delayed postoperative cerebrospinal fluid leakage (0.65%). No patient developed allergic reactions or systemic complications associated with the use of CAFG. CONCLUSIONS CAFG effectively provides hemostatic, adhesive, and safety performance. The timing and three-dimensional shape of CAFG-soaked oxidized regenerated cellulose and/or polyglycolic acid sheets solidification can be controlled with slow fibrin formation. The cost to prepare CAFG is similar compared with Com-FG products, and it can therefore be easily used at most institutions.