Koki Kadota

Proximal branching patterns of middle cerebral artery (MCA) in rats and their influence on the infarct size produced by MCA occlusion

The branching patterns of the proximal middle cerebral artery (MCA) and their influence on the infarct size following MCA occlusion in rats were studied. In the proximal part from the level of the olfactory tract, the MCA most often presented one surface branch extending anteriorly, with a variable number of surface branches extending posteriorly. We classified the branching patterns of the posteriorly extending surface branches as follows: Type 1 (57.5%), one prominent proximal surface branch; Type 2 (30.2%), no prominent branch but two or more small surface branches; and Type 3 (12.3%), no surface branches with a visible junction with the MCA but surface branches probably arising from the internal carotid artery at the origin of the MCA. When the proximal surface branches (especially that in Type 1) remained uncoagulated, the infarct size in both the cortex and striatum was significantly reduced compared with that when coagulation was proximal to the most proximal surface branch. The reduction of cortical and striatal infarct sizes was particularly prominent in the posterior portion. To increase the infarct size and reduce variability, it is suggested that the MCA trunk should be coagulated from the origin to the rhinal fissure including the surface branches.

Angiographically occult arteriovenous malformations.

Angiographically occult arteriovenous malformations not associated with clinically recognizable intracranial hemorrhage appear to be rare. We are reporting three cases of histologically proven arteriovenous malformations of the brain that were angiographically occult. These cases presented with seizures or attacks of dizziness, and were detected by computed tomography scan, radionuclide scan, or both. The preoperative diagnosis was granuloma in the first case and meningioma in the other two. After surgical exploration, biopsy revealed an arteriovenous malformation in each case. A review of 47 cases in the literature is tabulated and etiologies of the angiographically occult arteriovenous malformations are discussed. The routine use of computed tomography scan and timely, appropriate surgical intervention with the operating microscope for the removal of these deeply situated lesions is necessary for the diagnosis and therapy.

Pituitary adenoma with cholesterol clefts

Histologically, cholesterol clefts are often observed in craniopharyngioma, Rathke’s cleft cyst, and various granulomas. However, pituitary adenomas with cholesterol clefts are rare. A 46-year-old woman developed visual field disturbance. She had no history of severe headache that would suggest pituitary apoplexy. She presented with homonymous bitemporal hemianopsia and galactorrhea. Blood prolactin level was 63.1 ng/mL. Other hypophysial hormone levels were within normal range. Magnetic resonance imaging revealed a pituitary tumor with intratumoral cyst. The cyst showed high intensity on T1- and T2-weighted images. The tumor was demonstrated with iso intensity on T1-weighted image and with high intensity on T2-weighted image.She underwent trans-sphenoidal surgery. The tumor was soft, with yellowish, oily fluid, probably the cyst content. By light microscopy with hematoxylin and eosin staining, a typical chromophobic adenoma of the pituitary was identified. Immunostaining revealed immunoreactivity for ACTH in several cells. Many cholesterol clefts and several hemosiderin pigment containing macrophages were observed. Electron microscopy demonstrated a pituitary adenoma with sparse and small secretory granules and numerous lysosomes. The cyst was most likely caused by focal hemorrhagic infarction, followed by the formation of cholesterol crystals, the appearance of hemosiderin containing macrophages, foreign body product cells, and accumulation of lysosomes.

Transorbital Intracranial Penetration by Chopstick

A 38-year-old female was struck in the eye with a wooden chopstick during a quarrel with her husband. The chopstick penetrated and lodged in her brain. Neurological examination revealed left hemiparesis and hemihypesthesia and right cranial nerve palsy of the 2nd, 3rd, 4th, and 6th nerves and the 1st branch of the 5th nerve. Computed tomography revealed a narrow, straight, low-density extending from the right orbit via the right parasellar region to the pons. A right carotid angiogram revealed a traumatic low flow/low pressure carotid-cavernous fistula. Magnetic resonance imaging yielded a low signal intensity image passing through the orbit and extending to the pons. A craniotomy was performed by the pterional approach. So that the pons and neighboring structures would not be damaged, the chopstick was first gently divided into two portions at the prepontine cistern by a high-speed airdrill and then resected piece by piece. The intraorbital portion of the chopstick was lodged firmly in the bony structure of the superior orbital fissure and could not be removed. The authors discuss the characteristics of transorbital intracranial foreign bodies, with particular emphasis on diagnostic procedures and the indications for and timing of their surgical removal.

A Case of Holoprosencephaly Accompanied with Dysgenesis of the Cerebellum

A case of holoprosencephaly with dysgenesis of the cerebellum was reported. In computerized tomography scan, supratentorial structure had a huge monoventricle and very thin cerebral cortex in the frontal base. Tentorium was elevated to high level and in the posterior fossa, dysgenesis of cerebellum and large cerebrospinal fluid space were present. In left carotid angiogram, the azygous anterior cerebral artery ran along the frontal base. These investigations revealed that this case was a semilobar type of holoprosencephaly and an anomaly of the posterior fossa had the features of Dandy-Walker syndrome. For the progressive hydrocephalus, a ventriculo-peritoneal shunt was performed. Postoperatively, left inversed brachial angiogram was examined. From the left vertebral artery to the vertebral venous plexus, shunts were formed by radicular arteries. This finding suggests that there might be some vascular accidents in the developmental stage in such a case. In the cases of holoprosencephaly, the posterior fossa are usually normal. Therefore, such findings in our case seemed to be rare. Information from angiographical investigations should contribute to the understanding of such a case.