A case of concomitant occurrence of struma ovarii and malignant transformation of cystic teratoma.

A 77-year-old woman received a total abdominal hysterectomy and bilateral salpingo-oophorectomy because of a tumor in the left ovary. The surgical specimen measured 8.5x4.5x4.0 cm, and the solid lesion measured 4.0x3.5x3.5 cm. The solid lesion was diagnosed as struma ovarii. The cyst wall partially comprised squamous epithelium-like and ciliated columnar epithelium-like cells. The tumorous lesion of the cyst wall revealed a poorly differentiated adenocarcinoma. Immunohistochemically, the tumor cells were positive for cytokeratin7, and were negative for cytokeratin20 and thyroid transcription factor-1. The authors diagnosed that struma ovarii and other parats coexisted as a poorly differentiated adenocarcinoma that had arisen from a mature ovarian cystic teratoma. As for the identification of the origin of adenocarcinomas arising from mature ovarian cystic teratomas, more cases need to be identified and investigated.

Microvasculature of the human cerebral white matter: arteries of the deep white matter.

The vascular architecture of the human cerebral deep white matter was studied using soft X-ray and diaphanized specimens, achieved by intra-arterial injection of barium and vascular stain respectively, and also by electron microscopic examination of the corrosion cast of arteries in normal adult brains. The deep white matter arteries passed through the cerebral cortex with a few branches to the cortex and ran straight through the white matter. The arteries concentrated ventriculopetally to the white matter around the lateral ventricle. Anastomoses were noted around the ventricular wall at the terminals of the deep white matter arteries. No centrifugal branches irrigating the periventricular white matter from the lenticulo-striate arteries were observed in the present study. The presence of anastomoses among the terminal branches of deep white matter arteries protects against ischemic change or infarction in this area from an occlusion of a single deep white matter artery. This may lead to development of terminal zone infarction from ischemia or vascular diseases, affecting multiple deep white matter arteries. The subcortical and deep white matter arteries had thick adventitial sheaths and large adventitial spaces in the white matter but not in the cortex. The presence or absence of the adventitial space is regarded as another characteristic difference between the arteries in the white matter and cortex. This difference may influence pathological changes in vascular lesions in these respective areas.

Microvasculature of the human cerebral meninges.

In the present study, the human cerebral meninges were rich in blood vessels, but no capillaries were noted. The meningeal arteries ran over the veins where they crossed. Several arterial anastomoses existed on the cortical surface. The meningeal arteries were classified into four parts; the conducting artery approximately 700 microm in diameter, distributing artery approximately 200 microm in diameter, precortical artery approximately 60 microm in diameter and cortical artery approximately 30-40 microm in diameter. A single distributing artery supplied the area of approximately 3.5 x 2.0 mm on the brain surface. They further ramified into precortical arteries which stemmed cortical arteries. These precortical arteries had the distributing area of 1 mm2 and this distributing area was the same size as the width of human ocular dominant column of the visual cortex. Constriction, like a sphincter, was observed at the bifurcation of the distributing arteries. The cerebral blood vessels, which regulated the blood flow and reacted to autonomic nerve stimuli, seemed to correspond to the distributing arteries.

Ubiquitin-positive inclusions in ependymal cells.

Ubiquitin-positive inclusions (UbIs) have not been well studied in ependymal cells. Since we detected such UbIs in the central canals of the medulla and spinal cord while investigating UbIs in neurodegenerative diseases, we studied UbIs in the entire ependymal system of 42 patients with various neurological diseases and of 10 non-neurological controls. UbIs were located in the cytoplasm of the ependymal cells, and were round to oval in shape, measuring 4-11 microm in diameter. The UbIs were non-argyrophilic and undetectable by hematoxylin and eosin staining, but mildly reactive to periodic acid-Schiff staining with and without digestion. The UbIs were variably immunoreactive for anti-epithelial membrane antigen (EMA) antibody, but did not react with several other antibodies. The co-existence of ubiquitin and EMA was confirmed by confocal laser microscopy. Throughout the ependymal system, UbIs were variably found in ependymal cells as well as in subependymal cells. There was no significant difference in the overall incidence of either ependymal or subependymal UbIs between the patients with neurological diseases and controls. However, ependymal UbIs in the central canal were more frequent in the neurological disease patients than in controls, although there was no disease specificity. This is the first comprehensive report to show common occurrence of UbIs in the ependymal cells of adult human brains.

The microvasculature of the cerebral white matter: arteries of the subcortical white matter.

The microvascular architecture of the human cerebral subcortical white matter was studied. Most of the subcortical arteries ran straight through the cortex, but upon entering the white matter, they began to coil, loop, and spiral. Vascular stains showed wide spaces between the adventitial sheaths and blood vessels. The blood vessels coiled, looped, and spiraled within these wide adventitial spaces. This phenomenon was observed in the brains from persons ranging from the first to ninth decades of life and there were no statistically significant age-related correlations. Furthermore, there was no evidence of a reduction in the volume of white matter after fixation. Therefore, the observed tortuosity does not appear to be the result of shrinkage of brain tissue following fixation. While the mechanisms responsible for the subcortical arteries circuitry remain undetermined, this coiling architecture may serve as a trap for tumor cells and microorganisms passing through the blood stream, suggesting that these coiling arterial blood vessels may play a significant role in the pathogenesis of tumor metastasis and the brain abscess that frequently occurs in the gray-white matter junction.

Methylmercury poisoning in common marmosets--MRI findings and peripheral nerve lesions.

Common marmosets were used as model animals for methylmercury (MeHg) poisoning. Six marmosets were given MeHg of 5 ppm Hg in drinking water. The animals were divided into 3 groups of 2 each. The first group was examined for acute symptomatic MeHg poisoning. They were given MeHg for 70 and 90 days, respectively, to manifest severe symptoms. The second group was sacrificed after 38 days of MeHg exposure, when they had acute-subclinical MeHg poisoning. The third group of animals was exposed for 21 days, and then observed for 2.5 years without MeHg exposure. One of them showed typical symptoms of MeHg poisoning after MeHg exposure had ended, but the other one showed only slight symptoms without ataxia. This experiment demonstrated that MeHg causes pathological changes in neural tissues including the peripheral nerves in common marmosets. Furthermore, common marmosets were found to show MeHg-induced pathological changes similar to those in humans in the cerebrum and cerebellum.