Mixed ependymoma-neuroendocrine tumor of the lateral ventricle.

A histologically unique glioneuronal neoplasm occupying the lateral ventricle of a child was immunohistochemically and ultrastructurally characterized. Its principal component exhibited the characteristic features of ependymoma, whereas a minor population of neuroendocrine cells, occurring singly and in small clusters, lay scattered throughout the ependymoma component. Yet another unusual finding was the presence of numerous elastic fibers within the extracellular matrix. This tumor is considered to represent a true mixed neoplasm consisting of ependymal and neuroendocrine elements.

Small round cell neoplasms: can electron microscopy and immunohistochemical studies accurately classify them?

The answer to the question posed in the title, "Small Round Cell Neoplasms: Can Electron Microscopy and Immunohistochemical Studies Accurately Classify Them?", is obviously "yes"; but a qualified yes--generally yes, perhaps with expertise usually yes, but never just plain yes. Some cases certainly will defy the best attempts even of the most expert in the application of these "special" techniques. And embarrassing as it may be for those of us infatuated with the latest technology to admit, it is with the difficult case especially that old-fashioned technology so often must be depended upon. In his excellent recent appraisal of the role of a variety of special techniques in this application, Triche offers the following comment: "Overall, electron microscopy is probably the most universally useful of all diagnostic techniques other than light microscopy in round cell tumors." The data from our studies certainly point to the same conclusion. With each of the tumors, electron microscopy demonstrated itself to be more reliable than immunohistochemistry. Electron microscopy offers not only greater sensitivity and specificity, but also greater versatility. Immunohistochemistry allows hypothesis testing only. Electron microscopy, on the other hand, can provide answers even when the right questions are not being asked. For example, if a particular small round cell tumor under investigation happens in actuality to represent something other than the neuroblastoma which it is being considered (e.g., a granulocytic sarcoma, liposarcoma, Wilm's tumor, etc.), electron microscopy can reveal this fact, but a neuron-specific enolase stain cannot. Parenthetically, it should also be said that electron microscopy has proven particularly well suited to the examination of fine-needle aspiration specimens. The two spare many patients in our institution the need for a major operative procedure to establish a secure tissue diagnosis. Immunohistochemistry does have a role to play but it is, at least in our opinion, clearly secondary to that of electron microscopy. The concept of replacing electron microscopy with a battery of immunostains has often been advocated as an economic measure, but this argument begins quickly to lose its weight as the number stains included in the battery is increased to cover the diagnostic possibilities. Giving consideration to the capriciousness of some of these stains, there exists with this also an increasing possibility of a spurious or misinterpreted result leading to an errant diagnosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Post-infarction peripheral cysts of the lung in pediatric patients: a possible cause of idiopathic spontaneous pneumothorax.

Occlusion of the main pulmonary artery to the right lung in a newborn infant produced peripheral (subpleural) infarction of the lung and cyst formation. Two older infants were found at autopsy to have subpleural cysts of the upper lobes. One had had surgery for repair of an atrial septal defect and a patent ductus arteriosus eight months prior to death, while the second had died suddenly of carbon monoxide intoxication. The authors suggest that pulmonary arterial occlusion may have been responsible for cyst formation in all three cases and may produce cysts in other infants that lead to idiopathic spontaneous pneumothorax in older children and young adults. The presence of bronchopulmonary arteries in fetuses and newborn infants may provide the mechanism for the production of subpleural cysts following pulmonary arterial occlusion.

Hemolytic-uremic syndrome and T-cryptantigen exposure by neuraminidase-producing pneumococci: an emerging problem?

Hemolytic anemia, thrombocytopenia, and renal failure form a constellation of complications observed in patients infected with neuraminidase-producing pneumococci. The circulating enzyme causes exposure of the T-cryptantigen on cell surfaces to which most people possess a naturally occurring antibody. Antigen-antibody interaction activates effector systems that lead to the clinical manifestations. The syndrome is most frequently seen in infants, in whom it carries more than a 50% mortality rate. T-cryptantigen activation can be detected by demonstrating red cell agglutination by the peanut lectin Arachis hypogea. Plasma exchange and avoidance of blood products containing immunoglobins are of value in the management of this devastating complication of pneumococcal infection.

Combined portal and vena caval hypertension in Gaucher disease: The value of preoperative venography.

Portal hypertension in Gaucher disease is unusual; the seventh known patient with this complication is reported. Prior to portacaval shunting in this child, a localized obstruction of the inferior vena cava at the subdiaphragmatic level was demonstrated by caval manometry and inferior vena cavography. At autopsy, centrilobular hepatic fibrosis seemed to be responsible for the portal hypertension. Nodular enlargement of the right and caudate lobes of the liver was the cause of the caval obstruction; elevated caval resistance may have contributed to the portal hypertension and possibly was responsible for failure of a portacaval anastomosis. The value of preoperative inferior vena cavography in addition to arterial portography in children with portal hypertension is stressed.