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.

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.

Malignant hypertension in children secondary to chronic pyelonephritis: laboratory and radiologic indications for partial or total nephrectomy.

Severe renin-mediated hypertension was noted in 2 children as a result of selective renal damage from vesicoureteral reflux during the early years of life. In each case the reflux had been corrected successfully long before hypertension developed. In 1 case the late damage involved only 1 kidney and nephrectomy resulted in immediate relief of the hypertension. In the second case, even though both kidneys showed segmental scarring from calicectasis and chronic pyelonephritis, removal of the atrophied lower pole of 1 kidney made hypertension amenable to medical treatment and reduced excessive renin output to a fraction of the original high levels. The mechanism of renin-mediated hypertension in kidneys with segmental scars of chronic pyelonephritis is believed to be ischemia of the relatively normal renal cortex in proximity to areas of interstitial fibrosis, within which are tortuous interlobular and smaller arterioles with severe intimal thickening. Hypertrophy of normal renal segment occurs in young patients with segmental chronic pyelonephritis. To accommodate this enlargement the original calix develops an extension or elongation readily distinguishable from other dilated calices.