Takeyoshi Shimoji

Middle Fossa Arachnoid Cyst: Clinical, Neuroradiological, and Surgical Features

16 patients and 4 adult cases of small-or medium-sized middle fossa arachnoid cyst were subjected to various neuroradiological investigations and their results were analyzed in terms of possible mechanisms of cyst expansion. Based on the results of the investigations which strongly suggested that the cyst is an expanding lesion, all cases were surgically treated by the same techniques of craniotomy, excision of the outer cyst membrane, followed by a cystoperitoneal shunt, resulting in complete disappearance of the cyst concomitant with reexpansion of the surrounding brain and marked improvement in the clinical pictures of the patients.

Rathke cleft cysts

Three cases of Rathke cleft cyst are presented. The clinical symptoms were disturbances of visual acuity and visual fields, and a functional disorder of the hypophysis. In two cases, there were associated meningeal signs. This meningitis was considered to be aseptic and ascribable to leakage of the cyst contents into the subarachnoid space. In one patient, the cyst extended to the suprasellar cistern; a computed tomography scan revealed an enhanced capsule, high-density spotting in a low-density area inside the cyst, and enhanced areas. In another patient, the tumor was localized in the sella turcica; high-density spotting was seen. Based on this finding, we suggest that computed tomography scanning facilitates differentiation from other sellar lesions to some degree. Electron microscopic studies of a cyst with cilia revealed the presence of a coating material around cells with microvilli. On the basis of this finding, Rathke cleft cysts may be considered to be namely, endodermal, inclusions from the upper respiratory tract.

Surgically confirmed myelographic classification of congenital intraspinal lipoma in the lumbosacral region

Twenty-four cases of histologically confirmed congenital intraspinal lipoma of the lumbosacral region were studied by means of myelography with metrizamide. The findings were compared with intraoperative observations. Myelography with metrizamide clearly revealed the detailed intrathecal structures and allowed a classification of intraspinal lipomas into four types, in terms of their insertion into the conus medullaris: (1) dorsal type, either with direct or indirect (via an intrathecal stalk) insertion of the extrathecal lipoma into the dorsal aspect of the conus medullaris; (2) caudal type; (3) combined type; and (4) filar lipoma. Based on our surgical experience in untethering and decompression of the lesions, the classification was found to be useful in designing a safe and effective surgical procedure which minimized all possible trauma to the intrathecal neural structures.

Cavernous hemangioma with bone formation in a child: case report.

A 13-year-old girl suffering from seizures who was found to have hemangioma calcificans in the frontal lobe was surgically treated. The favorable postoperative course of our patient as well as reported cases suggest early excision of the lesion if it is located in an accessible area. Histological examination confirmed ossification with marrow in the lesion. The literature regarding ossification in the brain is discussed briefly.

An intracranial pseudoaneurysm in the distal middle cerebral artery in a child.

Intracranial pseudoaneurysms are rare, particularly in children and adolescents. They are characterized by the presence of organizing hematoma and fibrosis without true vascular elements. Most pseudoaneurysms result from events such as major trauma or infectious illness, and the development of pseudoaneurysm without a preceding incident is rare. We here describe a patient with a large pseudoaneurysm arising in the distal middle cerebral artery. A 10-year-old boy experienced a sudden onset of headache, nausea, and vomiting followed by loss of consciousness and was referred to our medical center. Brain computed tomography showed massive subcortical hemorrhage in the left temporal lobe. Digital cerebral angiography revealed a huge aneurysmal dilatation of the distal left M1 segment of the middle cerebral artery, with delayed filling and emptying of contrast media. Surgical resection of the aneurysm with evacuation of the hematoma yielded restoration of consciousness. Although the cause of aneurysm in this case is uncertain, this type of patient is seldom encountered; its etiology and mechanisms of onset are discussed with reference to the literature.

Transplacental induction of myeloschisis associated with hindbrain crowding and other malformations in the central nervous system in Long-Evans rats

Nine groups of 66 pregnant rats, grouped by gestation days 11 to 19, were subjected to a single, intragastric administration of ethylenethiourea (ETU). Cesarean section was performed on gestation day 20. No dam died following the ETU treatment, although a mortality as high as 21.2% was noted among the fetuses in this group; the remaining live fetuses were found to suffer from a high incidence of myeloschisis associated with hindbrain crowding. Exencephaly and abnormally enlarged head with occipital bossing due to the herniation of the mesencephalic tectum, with and without dilation of the mesencephalic and 4th ventricles, were induced among the fetuses of the dams given ETU at gestation days 12 and 13. Various degrees of hydranencephaly and dysplastic hydrocephalus were found among the fetuses of dams treated by ETU from gestation days 14 to 18. From the histological features of these malformations of the central nervous system (CNS), a possible mechanism in the induction of myeloschisis with hindbrain crowding induced by ETU is discussed, and compared with the previously reported similar malformations induced by trypan blue.

Reply to Dr. Ijichi’s group letter

We appreciate Dr. Ijichi’s group for being interested in our study. Since you warned our way of treatment of the mild trigonocephaly in 2000, we tried to follow asmuch as possible your suggestions. We went through the appropriate procedure for being approved by the ethical committee in our hospital with an informed consent form in which it is written that this treatment is not generally accepted. We would like to make this clear again that we are not treating autism. We were pointing out this from the very beginning. We are treating mild trigonocephaly with developmental delays and those symptoms mimicking autism. Maybe this may make Dr. Ijichi’s group misunderstand the situation. Besides these symptoms, the children we treated do have further clinical manifestations such as language delays; hyperactivities; motor delays; self-mutilations; sleeping disturbances, especially night terror; and drooling. Most of these symptoms are considered to be caused by the frontal lobe dysfunction. Finally, signs of increased intracranial pressure are also seen in some patients. Indeed, the treatment of this mild form of craniosynostosis started with our personal experience. The first several cases were done to improve the cosmetic deformity. Incidentally, these cases were associated with clinical symptoms, namely language delays and hyperactivity, but we did not think at that time that the surgical procedure would have improved them. However, there was an improvement in a short term in our first children which prompted us to plan since the sixth girl we operated on a preoperative and postoperative psychological evaluation based on several tests. In other words, we intentionally treated this sixth patient in order to improve her symptoms. After surgery, she made glorious improvement in short time period after surgery and continued developing well successively. Actually, she graduated high school last spring. This case was already introduced in reply to Dr. Ijichi’s comment in 2002 (14, reference no. from Dr. Ijichi’s letter). After treating many further cases, all of them accurately evaluated for psychomotor development both prior and after the surgical correction, we were convinced that the surgical procedure played a positive role for the improvement of the symptoms. We tried to understand the mechanisms causing their symptoms. On the neuro-radiological examinations, the subjects that had a median bony ridge in the forehead presented also on the CTscan examination a narrow forehead, smaller frontal lobes and tight anterior fossa, and profound digital markings. Also in surgery, the wide and thin sphenoid ridges compressing the opercular regions were noticed in many of the cases (Fig. 1). We also measured the intracranial pressure epidurally during surgery. We had seen raised intracranial pressures above 11 mmHg in more than 90 % of the cases (Table 1). We mention this observation to emphasize that we are not treating some obscure asymptomatic condition. Additionally, in CT scans carried out 6 months after surgery, it could be noted that there were remarkably reduced digital markings which led us to believe that surgery had decreased an abnormally high intracranial pressure (Fig. 1). * Takeyoshi Shimoji tk_simoji2008@angel.ocn.ne.jp

A Remaining Problem in Hemialexia

Hemialexia is defined in the narrow sense as an inability produced by a cerebral lesion in comprehension of written words presented in one of the two visual hemifields (Benson and Geschwind, 1969). However, in some patients diagnosed as hemialexic [e.g., Trescher and Ford’s (1937) case and Maspes’ (1948) cases] it is difficult to identify whether their disturbances are in comprehension (i.e., word-to-picture matching) or in reading aloud. Thus, hemialexia may be classified into two categories: type I hemialexia, an inability to comprehend written words, and type II hemialexia, an inability to read aloud written words or letters.

Reply to "Mild trigonocephaly with clinical symptoms"

It is now the patients’ parents (or guardians) who ultimately decide whether the operation should be performed, and their decision is based on thorough, frank discussions between the parents and ourselves. We noted the association between the developmental delays and trigonocephaly during the treatment of a patient with an almost completely typical case of mild trigonocephaly. We considered that with an increasing number of patients it would become more probable that the association would be confirmed, and therefore made presentations at meetings of academic societies and published papers in Japan and internationally. In the preamble to the Helsinki Declaration, the mission of medical doctors is described as the protection of patients’ health. The postoperative results, as reported in our paper, may be beneficial to patients. Since we received your advice, due procedures have been followed in terms of obtaining informed consent, and therefore the procedure is not considered to infringe on patients’ rights under the Helsinki Declaration. With regard to epidemiological efforts, we are clinicians and our mission is to treat the patients who consult us. Thus, as pointed out by Drs. Ijichi, we have not performed an epidemiological study. We believe that we have followed the best study design generally available in hospitals in Japan.

Callosal-Choroid Plexus Lipoma associated with Subcutaneous Lipoma

A callosal-choroid plexus lipoma associated with subcutaneous lipoma is presented. More than 100 cases of callosal lipoma with the characteristic X-ray findings have been reported. However, such a combined occurrence as this is very rare. Only 14 cases have been published in the literature, and the majority of the cases were accompanied by the dysraphic lesions. The operative findings of this case revealed that the subcutaneous lipoma was not continuous with the callosal lipoma. These cases were analyzed with emphasis on the association of dysraphism in the pathogenesis of intracranial lipomas.