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Biomedical subjects

M G Netsky

Publications and source records attributed to M G Netsky.

At least 19 recordsLinked to original sources
PubMed1979

Phagocytic astrocytes and neurons in old encephalomalacia.

Cytoplasmic accumulation of hemosiderin was observed within astrocytes and neurons as well as in other phagocytes associated with old encephalomalacia. The first patient was 3 years old when she died with malnutrition and superimposed infection. A cortical infarct had been caused by an old thrombus in a small artery. The second case was a 9-year-old girl who had old encephalomalacia in the pineal region after extirpation of a pineoloma. The third patient was a 22-year-old man who had a cortical infarct from an embolus associated with chronic rheumatic endocarditis. Granules of hemosiderin had accumulated within the perikaryon of many astrocytes and other phagocytes in all cases, and in a few neurons in the second instance. Review of the literature reveals that cytoplasmic accumulation of particulate matter has been described infrequently with regard to neuroepithelial derivatives. Our findings indicate that astrocytes and neurons as well as derivations of mesenchyme may act as phagocytes of old blood.

Adult↗
PubMed1979

Combined neurilemmoma and angioma. Tumor of ectomesenchyme and a source of bleeding.

Eight cases are described of intracranial and peripheral neoplasms composed of mixed neurilemmoma and hemangioma. It is proposed that ectomesenchyme can differentiate into neurilemmoma and angioma. The latter may be related to recently described angiogenetic factors, or to developmental factors as in rare cases of arterial angiomas. The angiomatous part may be common, but has often been overlooked. The presence of abnormal vessels, whether in kind or in number, helps explain various biological features of neurilemmoma. These vessels frequently bleed within the tumor, which results in the characteristic hemosiderin-laden macrophages. Bleeding may also occur into the cerebrospinal fluid (CSF) to create xanthochromia. The frequent increase in CSF protein in cases of neurilemmoma is attributed to transudation of serum from abnormal vessels. Less commonly, bleeding may be sufficient to cause subarachnoid hemorrhage. The dense collagen usually associated with these angiomas accounts for the relative infrequence of major hemorrhages.

Aged↗
PubMed1979

Relation of age and cerebral ventricle size to central canal in man. Morphological analysis.

The central canal of the spinal cord in man with and without hydrocephalus was studied histologically. The lumen was patent in most patients in the first two decades of life. Cells lining the canal in the prenatal and newborn state and in the first decade of life were predominantly pseudostratified ciliated epithelium. In the second decade, the epithelium became simple columnar or cuboidal. The central canal closed in most cases after the age of 20 years, secondary to proliferation of ependymal cells and astrocytes. Mechanisms whereby the number of glial cells increase are considered. The canal was closed in all adults with normal ventricular size, and in 94% of persons with various degrees of hydrocephalus. In the remaining 6% of cases with hydrocephalus, the lining of the canal resembled that seen in the first two decades, and could have acted as a pathway of cerebrospinal fluid (CSF) absorption. Three cases of severe hydrocephalus in the first two decades of life were encountered; the central canal was patent in one, and occluded in two. Based on these data, the canal was not a significant pathway of CSF absorption in most instances of hydrocephalus and in persons with dilated ventricles who were older than 20 years of age.

Adolescent↗
PubMed1979

Empty sella secondary to suprasellar colloid cyst of foregut (respiratory) origin. Case report.

An enlarged sella turcica was discovered in a 40-year-old man who had bitemporal headaches. A pneumoencephalograph revealed a third ventricular cyst, dilated lateral ventricles, and an empty sella. The colloid cyst was lined by foregut epithelium, probably originating in the respiratory tract, and dense connective tissue. This case is the first instance of an empty sella associated with a colloid cyst of the third ventricle. It is proposed that enlargement of the mass in the third ventricle caused increased pulsation pressure of the cerebrospinal fluid, and that in the presence of an incompetent diaphragma sellae the subarachnoid space expanded into the sella. The origin of third ventricle cysts is reconsidered. It is concluded that suprasellar colloid cysts may arise from endoderm, ectoderm, neuroepithelium, or a combination of these epithelia.

Adult↗
PubMed1979

Melanosis of the choroid plexus, ependyma, subependymal neuroglia, and dentate and trigeminal motor nuclei: observations on the choroidal and ependymal cilia.

Melanosis of the choroid plexus, ependyma, subependymal neuroglia of the fourth ventricle, and dentate and trigeminal motor nuclei was found in a 50-year-old man who died with cor pulmonale, hypertensive cardiovascular disease, and intracerebral hemorrhage. This case is the first known example of melanosis not associated with neurocutaneous melanosis to involve multiple structures of the brain. Nonenzymatic conversion of lipofuscin into melanin is suggested as the mechanism of the melanosis. Cilia of the choroidal epithelium and ependyma were identified in this case, despite a long delay in postmortem examination. These observations on choroidal epithelium confirm previous reports that the choroid plexus of man is ciliated, as in other mammals and lower vertebrates.

Brain Diseases, Metabolic↗
PubMed1979

Light and electron microscopic observations of blood vessels in neurilemoma.

A study of 105 cases of neurilemoma disclosed frequent alterations of blood vessels, including hyalinized walls. Many vascular walls were formed by tumor cells. Two cases were analyzed by electron microscopy, and showed fenestrae, patent interendothelial gap junctions, and leakage of RBCs. The presence of erythrocytes in the gap junction and outside vessels is a factor acounting for xanthochromia of the CSF, and serum leakage for the frequent increase in CSF protein in cases of neurilemoma. Attenuation of endothelial cells increases the liability of vessels to bleed within the tumor. Massive bleeding may cause subarachnoid hemorrhage on rare occasions. Hyalinized vessels and dense collagen are features contributing to the relative infrequence of major hemorrhage. Evidence is presented that Schwann and perineural cells are similar.

Blood Vessels↗
PubMed1978

Combined congenital vascular anomalies and neuroepithelial (colloid) cysts.

We present two unique cases of intracranial congenital lesions of different origins. A 29-year-old woman had an angioma of the choroid plexus of the third ventricle and paraventricular region; a small neuroepithelia cyst was also included in the lesion. This case is the first known description of a choroidal angioma in the third ventricle. The other patient, a 39-year-old woman, had a ruptured saccular aneurysm at the junction of the anterior communicating and left anterior cerebral arteries, a cerebellar hemangioma, and a small neuroepithelial cyst with numerous papillary infoldings in the pineal region. The presence of choroid plexus in this cyst is further evidence of a developmental malformation. Review of the literature disclosed that vascular malformations and neuroepithelial cysts are occasionally associated with other congenital anomalies. The findings support the congenitally derived nature of these lesions.

Adult↗
PubMed1977

Brain tumors of mixed tissue origin: staining procedures to distinguish glial from connective tissue.

Described is a unique mixed intracerebral tumor composed of schwannoma, piloid astrocytoma, and angiomatous malformation. Review of conventional staining methods for distinguishing glial from connective tissue fibrils reveals that Mallory's phosphotungstic acid-hematoxylin (PTAH) method is less specific than is generally recognized. Knowledge of these pitfalls, combined with use of hematoxylin and eosin stains, and reticulum impregnations are currently most useful in making the distinction by light microscopy. Criteria for malignancy of schwannoma and other mesenchymal tumors should be based on number of mitotic figures and invasiveness rather than on pleomorphiam of cells. Prior knowledge of the location of the tumor may lead to diagnosing some schwannomas as other types of tumor.

Adult↗
PubMed1977

Multiple neuroepithelial (colloid) cysts: association with other congenital anomalies.

A 4-year-old boy had three neuroepithelial cysts, one in the third ventricle and two in the supratentorial subarachnoid space, and also had stenosis of the cerebral aqueduct, obstructive internal hydrocephalus, frontoethmoidal meningoencephalocele, and right microphthalmia. The occurence of these combined lesions supports the congenitially derived nature of the cysts. The cysts originated from neuroepithelium including ectopic ependyma-lined structures. The exception may be those cysts arising in or near the floor of the third ventricle; these cysts could be derived from the cleft of Rathke's pouch, an endodermal derivative. Folding of the neuroepithelium in contact with mesenchyma or neuroglial tissue is proposed as the mode of formation of most "colloid" cysts. Review of the literature as well as our experience indicates that neuroepithelial cysts are widely distributed throughout the central nervous system.

Abnormalities, Multiple↗
PubMed1976

Pigmented ganglioneuroblastoma: relation of melanin and lipofuscin to schwannomas and other tumors of neural crest origin.

An unusual case of ganglioneuroblastoma containing melanin is presented. Electron microscopy revealed various stages of development of melanosomes in neoplastic cells of Schwann, the first direct demonstration in human material that these cells are malanogenic. The frequent occurrence of neuromelanin in autonomic ganglia and in ganglioneuromas is interpreted as the presence of altered lipofuscin. Review of ultrastructural and other observations indicates a relation between various pigmented tumors, the cell of Schwann, and other cells arising from the neural crest.

Adolescent↗
PubMed1976

Melanosis of the choroid plexua.

A unique case of melanosis of the choroid plexus in a 74-year-old man who died of hypertensive cardiovascular disease is described. The cerebral lesion did not cause symptoms. The proposed pathogenesis is the conversion of choroidal epithelial lipofuscin into melanin. Our findings also may explain the origin of a previously reported primary malignant melanoma of the choroid plexus and of black cortical adenomas of the adrenal gland.

Aged↗
PubMedDate not supplied

Melanotic neuroectodermal tumors of the brain and skull.

A case of melanotic neuroectodermal tumor in the cerebellum of a 21-year-old man is presented. Melanin was found mainly in small neoplastic cells rather than in large epithelioid cells. The tumor also contained neurons, as well as neoplastic tissue of ependyma, choroid plexus; and astrocytes. We propose that this neuroectodermal tumor resulted from a combination of cells originating in the neural crest and in the neural tube. The small cells have been described as medulloblasts, but they may be poorly differentiated ependymal cells, or, sympathicoblasts. The presence of pigment in these cells is compatible with an origin in the neural crest. The so-called melanotic progonoma, occurring most often in the maxilla of infants, is reviewed in relation to the melanotic neuroectodermal tumor of the brain. The tumor in facial bone occurs in adults as well as infants, in locations other than the maxilla, and has malignant forms. Melanotic neuroectodermal tumors, whether in brain or bone, are therefore similar in behavior as well as histologic appearance. The finding of similar tumors in these different locations is readily explained embryologically.

Adult↗