Yoshihiko Takahashi

Pineal malignant rhabdoid tumor with chondroid formation in an adult.

A pineal tumour in a 27‐year‐old male is presented with the characteristic histological features of a pineal malignant rhabdoid tumor (MRT) with chondroid formation. Occasionally, tumor cells contained a single well‐demarcated hyaline globular inclusion within the cytoplasm adjacent to the nucleus. The stroma of these tumors tends to be densely hyalinized and become chondroid. Immunohistochemical staining was positive for vimentin, epithelial membrane antigen, chromogranin A, synaptophysin, neuron‐specific enolase, S‐100 protein, and muscle actin. Despite surgery and radiochemotherapy, the tumor recurred in the pineal region and metastasized to the lower lobe of right lung. The patient died 2 years after the initial diagnosis. This is the second published case of central nervous system‐MRT appearing in an adult. The clinical and pathological features of pineal MRT in this patient are presented.

Intraventricular Malignant Triton Tumour

Summary¶ The authors present the clinical and pathological features of a malignant triton tumour (MTT) in the lateral ventricle with neurofibromatosis type 1. A 57 year-old man presented with disorientation and memory disturbance. A Computed tomographic scan and magnetic resonance imaging studies revealed an enhancing lesion in the left lateral ventricle. A parieto-occipital transcallosal approach was taken and resection of the lesion was performed. The operative findings suggested that the tumour arose from the perivascular nerves. The final pathological diagnosis was a MTT. This is the first case of an intraventricular MTT. Aggressive treatment including radical surgery combined with radiochemotherapy is recommended for a MTT of the central nervous system.

Syringobulbia Caused by Delayed Postoperative Tethering of the Cervical Spinal Cord – Delayed Complication of Foramen Magnum Decompression for Chiari Malformation

Summary Postoperative tethering of the high cervical spinal cord is a rare cause of neurological deterioration after foramen magnum decompression (FMD) with duraplasty for Chiari type I malformation. A review of the literature revealed that only 5 cases have been reported. This entity is not widely known to occur as a complication of the common surgical procedure for Chiari type I malformation. A 17-year-old boy experienced rapidly progressive neurological deterioration over a 3-month period. FMD and duraplasty with lyophilized cadaver dura had been performed 8 years previously. Follow-up MR images showed that the cerebrospinal fluid (CSF) space dorsal to the cord was gradually disappearing and that syringobulbia had developed. Opening the dura mater of the posterior fossa revealed dense fibrous scarring, arachnoid thickening over the cervicomedullary area, and tethering the cord to the dura from the medulla to C2. The adhesions were dissected free, and the tethering was released. A syringosubarachnoid (SS) shunt was inserted and duraplasty was performed with an expended polytetrafluoroethylene sheet (Gore-Tex). Postoperative MR images demonstrated that the syringobulbia had completely collapsed and that a dorsal CSF space was present. Follow-up MR images provided significant information on the cervical spinal cord tethering after FMD with duraplasty for Chiari malformation. We encourage sharp surgical detethering and duraplasty with Gore-Tex to avoid retethering. Early recognition and treatment of this unusual but important complication are emphasized.

New surgical treatment of middle fossa arachnoid cyst.

BACKGROUND A new surgical treatment of middle fossa arachnoid cyst is reported. The benefit of our surgical procedure is to maintain the physiologic pathway of the cerebrospinal fluid (CSF) without a shunting procedure. METHODS Following a small frontotemporal craniotomy, a linear incision in the outer wall of the cyst is made. The basal subarachnoid cisterns and distal sylvian cisterns are widely opened microsurgically. The outer wall of the cyst is then closed to prevent CSF leakage (arachnoidplasty). RESULTS We have experienced six patients who underwent this new surgical treatment. All their cysts showed nor or delayed influx of the contrast medium on preoperative computed tomography cisternogram. A favorable outcome was attained in the long-term follow-up without any complications. CONCLUSIONS The present technique was designed to secure physiologic CSF circulation and to avoid the use of a shunting system. A total of six patients treated with our new technique have been followed-up 6 years, and a good clinical outcome has been observed in all of them without complications.

Fatal hemorrhage from rupture of the intracranial internal carotid artery caused by aspergillus arteritis.

To the best of our knowledge, this is the first reported case of combined intracranial and extracranial hemorrhage due to aspergillus cerebral arteritis. Knowledge of the imaging and the importance of early diagnosis and treatment are emphasized. A 78 year old man developed progressive right-sided visual impairment and diplopia. Magnetic resonance imaging demonstrated a mass lesion located in the right orbital apex, with extension to the cavernous sinus and the right middle cranial fossa. Cerebral angiography showed no aneurysmal dilatation. He was scheduled for transnasal biopsy. However, the patient died of massive epistaxis and intracranial hemorrhage. Postmortem examination revealed an aspergillus granuloma of the orbit and the skull base involving the intracranial and extracranial internal carotid artery. Aspergillus fumigatus was identified by culture. The characteristic feature of the fungal infection is a low-intensity signal on T2-weighted magnetic resonance images. This finding may be useful in diagnosing fungal infection.

The ultrastructure of the primate arachnoid granulation, studied with the scanning and transmission electron microscopes

The ultrastructures of the primate arachnoid granulations were observed using the scanning (SEM) and transmission (TEM) electron microscopes. The endothelial cells were slender and overlapped each other. Extracellular spaces which were composed of a network of arachnoid cell processes crisscrossing each other three-dimensionally, were observed under the endothelium. By treating with NaOH (20°C), the collagenous fibers in the specimen were exposed under the SEM. The arachnoid granulations were entirely covered with the fibrous capsule, which was composed of wavy collagenous fibers. Many pores (1–2 μm) were observed on the fibrous capsule. These morphological structures may be closely related to the mechanism for cerebrospinal fluid absorption.