Katsushi Taomoto

Platelet Function and Spontaneous Thrombolytic Activity of Patients with Cerebral Infarction Assessed by the Global Thrombosis Test

Measurements of platelet reactivity and assessment of the efficacy of antiplatelet drugs are widely recognized as pre-requisite for the diagnosis and treatment of stroke patients. A recently established shear-induced platelet reactivity test using non-anticoagulated blood (the Global Thrombosis Test) has facilitated measurements of physiologically relevant platelet function and thrombolytic activity. 195 healthy volunteers, not taking antiplatelet drugs or anticoagulants, and 185 patients with acute cerebrovascular diseases were enrolled. The effect of antiplatelet drugs on platelet function and thrombolytic activity was assessed using the Global Thrombosis Test after 14 days of medication. The occlusion time (OT), an index of platelet reactivity, in healthy controls was 284.9 ± 92.2 s. The lysis time (LT), an index of thrombolytic activity, in healthy controls was 2,231 ± 1,223 s. Both times had no significant difference between males and females. The OT of all stroke patients was 210.3 ± 140.8 s and was shorter than that of the healthy controls (284.9 ± 92.2, p < 0.0001). The LT of all stroke patients was 3,159 ± 1,549 s and was longer than that of the controls (2,231 ± 1,223, p < 0.0001). Medication significantly prolonged the OT from 184.5 ± 150.6 s (before) to 295.3 ± 208.1 s (after) in all patients, indicating a reversal of the hyper-platelet reactivity. In addition, medication shortened the LT from 3,924 ± 1,718 s (before) to 3,107 ± 1,794 s (after) in all patients. A prothrombotic state exists in stroke patients due to enhanced platelet function and suppressed thrombolytic activity. Medication improved these physiological parameters of haemostasis.

Cytologic feature by squash preparation of pineal parenchyma tumor of intermediate differentiation

Pineal parenchyma tumor of intermediate differentiation (PPTID) is a very rare intracranial tumor, and pathological investigation limited to immunohistological and ultrastructural analyses have been published to date. Although intraoperative cytology is one of the important approaches for initial diagnosis in brain tumors, no or little studies on cellular morphology of PPTID have been demonstrated due to its rarity. We report here cytological features of PPTID obtained from stereotactic surgical specimens in a case of 27‐year‐old female manifested by dizziness and diplopia. Brain MRI revealed an unhomogeneously enhanced, large‐sized tumor (56 × 52 × 60 mm) mainly located in the pineal region expanding from the midbrain to superior portion of the cerebellum and the fourth ventricle. Squash cytology showed increased nucleocytoplasmic ratio, hyperchromatic nuclei, and small rosette‐like cell cluster but cellular pleomorphism was mild to moderate and necrotic background was not observed. Histology showed high cellularity, moderate nuclear atypia, and small rosette formation but neither bizarre tumor cells nor necrosis was present. Mitotic counts were very low (less than 1 per 10 high‐power fields) and the MIB‐1 labeling index was relatively high (10.1%). Tumor cells were immunohistochemically positive for neural markers such as synaptophysin, neurospecific enolase but not for glial fibrillary acidic protein or S‐100. In some parts, cells were strongly reactive for neurofilament protein. Taken together, we made a final diagnosis of PPTID. This is the first presentation of cytological analysis by squash preparation that gives an important clue to accurate diagnosis of pineal parenchymal tumor and to understand its malignant potential. Diagn. Cytopathol. 2008;36:749–753.

Cerebral and spinal cord tanycytic ependymomas in a young adult with a mutation in the NF2 gene

We studied one frontal lobe tumor and multiple spinal cord tumors (one in an extramedullary location) that had been resected from a 24‐year‐old man. The frontal lobe tumor was well demarcated and non‐infiltrating, and consisted of eosinophilic, elongated fibrillary cells arranged in a fascicular pattern. A similar histology was reproduced in the spinal cord tumors, with additional areas showing standard features of ependymoma. Immunohistochemical and ultrastructural observations revealed that all the tumors were ependymal in nature with positivity for GFAP and epithelial membrane antigen and negativity for oligodendrocyte transcription factor 2, showing intra‐ and intercellular microrosettes, leading us to a diagnosis of tanycytic ependymoma for the frontal lobe tumor and tanycytic ependymoma with ordinary ependymomatous component for the spinal cord tumors. The spinal extramedullary tumor was a schwannoma. Importantly, a heterozygous truncating mutation in the NF2 gene was identified in the blood lymphocytes from the patient. It is known that multiple nervous system tumors can occur in neurofibromatosis type 2 (NF2), which is caused by mutation in the NF2 gene, and that occurrence of ependymoma, including the tanycytic variant, can be associated with this genetic condition. The present case provides further information about the clinicopathology of tanycytic ependymoma with details of the immunohistochemical, ultrastructural and genetic features.

A rare case of malignant glioma suspected to have arisen from a cavernous sinus

A 55-year-old woman presented with a right trigeminal dysfunction (dysesthesia) initially, followed by right oculomotor and abducens paresis lasting 1 month. Neuroimaging studies showed an enhanced mass in the right cavernous sinus extending to the trigeminal ganglion. The extraparenchymal tumor located around the right trigeminal ganglion was totally removed, except for an intracavernous lesion, by the orbitozygomatic approach. The solid tumor was completely separated from the brainstem and seemed to be a trigeminal schwannoma arising from the trigeminal ganglion or cavernous sinus at surgery. A histological examination, however, found a typical malignant glioma that consisted primarily of astrocytic tumor cells. Immunohistochemical staining showed the tumor cells stained intensely for GFAP, S-100 protein, and vimentin, but not for NFP, Schwann/2E, CD34, and CD68. The mean MIB-1 index was 12.4%. The tumor recurred after a short time, and then it rapidly disseminated into the subarachnoid space and left the cerebral hemisphere. The patient died 1 year after the initial symptoms in spite of aggressive surgery, radiation, and chemotherapy with temozolomide. There are no previous reports of a malignant glioma arising from either the cavernous sinus or the trigeminal ganglion. From the pathogenetic point of view, this malignant glioma is an extremely rare case that developed clinically and neuroradiologically from the cavernous sinus and was suspected be being derived from ectopic glial tissue.

Retrocarotid Infracommunicating Approach for Parasellar and Interpedunclar Tumors

What is minimally invasive? There are many answers: for example less operation time, less blood loss, less damage to the brain, nerves and blood vessels and safety. I think the concept of minimally invasive neurosurgery is less complications and maximum efforts. Surgeons should evaluate the grade of complications preoperatively. High grade complications are death, consciousness disturbance, dementia, aphasia and hemiparesis. Medium grade complications are cranial nerve palsies. Low grade complications are cosmetic problems. In order to minimize major complications, we must avoid vascular injury first [1].