Haruo Matsuno

Microsurgical anatomy of the posterior fossa cisterns.

The microsurgical anatomy of the posterior fossa cisterns was examined in 15 cadavers using 3X to 40X magnification. Liliequists membrane was found to split into two arachnoidal sheets as it spreads upward from the dorsum sellae: an upper sheet, called the diencephalic membrane, which attaches to the diencephalon at the posterior edge of the mamillary bodies, and a lower sheet, called the mesencephalic membrane, which attaches along the junction of the midbrain and pons. Several other arachnoidal membranes that separate the cisterns were identified. These include the anterior pontine membrane, which separates the prepontine and cerebellopontine cisterns; the lateral pontomesencephalic membrane, which separates the ambient and cerebellopontine cisterns; the medial pontomedullary membrane, which separates the premedullary and prepontine cisterns; and the lateral pontomedullary membrane, which separates the cerebellopontine and cerebellomedullary cisterns. The three cisterns in which the arachnoid trabeculae and membranes are the most dense and present the greatest obstacle at operation are the interpeduncular and quadrigeminal cisterns and the cisterna magna. Numerous arachnoid membranes were found to intersect the oculomotor nerves. The neural and vascular structures in each cistern are reviewed.

Branches of the Persistent Primitive Trigeminal Artery–An Autopsy Case

An adult autopsy case of the persistent primitive trigeminal artery (PTA) is reported. At the origin of the PTA in the cavernous portion of the internal carotid artery, the PTA branched into the meningohypophyseal trunk and the artery of the inferior cavernous sinus. This might indicate that these arteries were formed at the same embryonic stage. At the cisternal portion of the PTA in the posterior fossa, it also branched into the trigeminal nerve root and pons on the way to the basilar artery. The PTA might have functions for the normal structures even in the case of adults. The PTA passed through the dural foramen, which was located medial to Meckels cave, and connected with the basilar artery. The diameter of the PTA decreased markedly at the foramen. The dural foramen might be the site of regression of the PTA during the embryonic stage.

Posterior fossa chondroma arising from the tentorium: a case report.

Intracranial chondroma is a rare tumor with an estimated incidence of 0.1–0.2 percent of all intracranial tumors [9]. The most common site of origin is the synchondrosis of the skull base. Some authors have reported intracerebral [2] or meningeal chondroma [1,3,8,14,15]. However, posterior fossa chondroma arising from the tentorium is rare. Here we report a case of a tentorial chondroma in the posterior fossa.

A study of CSF cells by 3H-thymidine autoradiography and cytology regarding the subarachnoid dissemination of brain tumor.

SummaryIn order to evaluate subarachnoid dissemination of brain tumor, the cerebrospinal fluid (CSF) cells of 104 patients with brain tumor were examined by 3H-thymidine autoradiography and cytology. As a control CSF cells from 34 patients with non-neoplastic disease were examined by the same method. Immediately after withdrawal by lumbar or ventricular puncture, the CSF was incubated with an admixture of 3H-thymidine at a concentration of 1–2 μCi/ml CSF at 37°C for 1 h. The CSF cells were collected by sedimentation or centrifugation and the microautoradiographic procedure was performed. The labeling index (LI) of CSF cells was counted excluding small lymphocytes and polymorphonuclear leukocytes. Labeled CSF cells were found in 33 of 34 cases of non-neoplastic cases. The mean LI of CSF cells in non-neoplastic cases was 0.4% and the highest was 1.7%. Cytological study revealed neoplastic CSF cells in 15 of 104 cases of brain tumor. A LI exceeding 1.7%, which was the highest in non-neoplastic cases, was encountered in 24 of 104 neoplastic cases. The highest LI in neoplastic cases was 14.4% in a case of primary reticulum cell sarcoma of the brain. High labelings were seen in cases of primary brain sarcoma, metastatic carcinoma, meningeal leukemia and pinealoma. In cases of glioma, even though malignant, the LI was relatively low in most cases. High LIs were parallel with the result of cytology in most cases. It was suggested that either 3H-thymidine autoradiography or cytology of CSF cells alone was not always conclusive for the diagnosis of subarachnoid dissemination of brain tumor, but by using both methods the diagnosis would be obtained with more accuracy.ZusammenfassungUm eine subarachnoideale Ausbreitung des Tumors auszuwerten, wurden die Liquorzellen von 104 Patienten mit Hirntumoren mittels 3H-Thymidin-Autoradiographie und Cytologie untersucht. Zur Kontrolle wurden die Liquorzellen von 34 Patienten mit nicht-neoplastischen Krankheiten des zentralen Nervensystems nach der gleichen Methode untersucht. Sofort nach der Lumbal- oder Ventrikelpunktion wurde der entnommene Liquor in vitro bei 37°C für 1 Std. mit 3H-Thymidin (1–2 μCi/ml Liquor) inkubiert. Die Zellen wurden durch Sedimentation oder Zentrifugation gesammelt und dann ein mikroautoradiographisches Verfahren angewandt. Der Markierungsindex der Liquorzellen wurde nach Ausschluß der kleinen Lymphocyten und Granulocyten berechnet. Markierte Liquorzellen wurden in 33 von 34 nicht-neoplastischen Fällen gefunden. In nicht-neoplastischen Fällen war der durchschnittliche Markierungsindex der Liquorzellen 0,4% und der höchste 1,7%.Die cytologische Untersuchung zeigte neoplastische Liquorzellen in 15 von 104 neoplastischen Fällen. Ein Markierungsindex von Liquorzellen über 1,7%, d. h. dem höchsten Wert in nicht-neoplastischen Fällen, wurde in 24 von 104 neoplastischen Fällen beobachtet. Der höchste Markierungsindex der Liquorzellen bei Hirntumoren war 14,4% (primäres Reticulumzellsarkom des Gehirns). Hohe Markierungsindexe wurden auch bei primären Gehirnsarkomen, metastatischen Carcinomen, meningealen Leukämien und bei Pinealomen angetroffen. In Fällen von Gliomen — auch bösartigen — war der Markierungsindex der Liquorzellen relativ niedrig. Der hohe Markierungsindex der Liquorzellen entsprach in den meisten Fällen dem Vorkommen von neoplastischen Zellen. Abschließend wird darauf hingewiesen, daß weder die 3H-Thymidin-Autoradiographie noch die Cytologie allein die Beurteilung einer subarachnoidealen Aussaat eines Tumors endgültig gestattet, daß aber durch Anwendung beider Methoden eine größere Genauigkeit erreicht werden kann.

Cerebellar medulloblastoma associated with lumbosacral syringomyelia

SummaryIn a 9-year-old boy with cerebellar medulloblastoma, lumbosacral syringomyelia and a cystic change in the olfactory tract were found at autopsy. The cause of the syringomyelia and the olfactory tract cyst was considered to be secondary to dissemination of the tumor and its treatment.ZusammenfassungIn einem Fall von Kleinhirnmedulloblastom bei einem 9jährigen Knaben zeigte die Autopsie eine Syringomyelie im Lumbosakralmark und eine zystische Höhle des Tractus olfactorius. Es wird angenommen, daß beide Höhlenbildungen durch die subarachnoidale Tumorausbreitung sowie durch die Bestrahlung und die Chemotherapie verursacht wurden.