J. Bruce Beckwith

Ultrastructure and Histogenesis of the Renal Tumors of Childhood: An Overview

This review discusses the ultrastructural and immunohistochemical features of the common childhood renal tumors, with an emphasis on their diagnostic usefulness. Speculations regarding their histogenesis also are presented, with the hope that these may serve to diminish some of the confusion surrounding the classification of these morphologically diverse lesions.

Pathologic delineation of the papillonodular type of cystic partially differentiated nephroblastoma. A review of 11 cases

Eleven cases of a previously unrecognized papillonodular variant of cystic partially differentiated nephroblastoma (CPDN) are described. This type of CPDN has all the features of the conventional type of CPDN; however, in addition, there are grossly demonstrable papillonodular projections extending from the septa into the cyst lumina. The septa do not show any expansile tumor masses. Like most cases of the conventional type, this new type of CPDN was usually diagnosed in infants. Nephrectomy (total in 10 and partial in 1) was done in these cases. Additional chemotherapy with or without radiation therapy was given in seven cases. No recurrence was noted during the period extending from 21 months to 8 years in the eight cases in which follow‐up data are available. Nephrectomy with regular follow‐up visits for possible recurrence may be the management of choice. Pathologists should be aware of this variant of CPDN so that overtreatment can be avoided. The revised criteria for CPDN can be summarized as follows: (1) The discrete entirely cystic tumor contains luminal papillonodules in some cases. (2) Septa and the papillonodules, when present, are the only solid portion of the tumor and contain blastemal cells admixed with their normal and aberrant derivatives. (3) The tumor without and with papillonodules is classified as a conventional and papillonodular type of CPDN, respectively.

The National Wilms’ Tumor Study: A Progress Report

Wilms’ tumor was virtually incurable before pediatric surgeons, notably Ladd1, perfected their surgical techniques. Steady improvements thereafter added radiation therapy2 and chemotherapy. The routine postoperative use of actinomycin-D, as reported by Farber3, produced a two-year survival rate of 81% in patients managed from the outset by an experienced team using combination therapy. Wolff and his colleagues4 demonstrated the value of cyclic actinomycin-D given over a prolonged period after operation, and otherss 5,6 showed that vincristine sulfate was effective in the management of these children.

Intriguing Case: Primitive Pelvic Sarcoma Resembling Clear Cell Sarcoma of Kidney

A 46-year-old man presented with a cytologically bland testicular tumor composed of spindle cells that showed both epitheliallike (ie, true desmosomes and tonofilamentlike structures) and myogenous differentiation (ie, thin filaments with focal densities and alpha-smooth muscle actin immunoreactivity). Tumor cells were immunoreactive for vimentin and S-100 protein but negative for cytokeratin and desmin. Peritubular myoid cells are present in the normal testis; contain subplasmalemmal micropinocytotic vesicles; show thin filaments with focal densities; and are reactive with desmin, vimentin, and alpha-smooth muscle actin. They have no desmosomes and lie outside the basement membrane of the seminiferous tubules; thus they are not true myoepithelial cells (a cell type not present in the testis). Paradoxically, the current tumor appeared to show bidirectional differentiation, mimicking both a peritubular myoid spindle cell and an epitheliallike cell (possibly similar to the granulosa cell or rete testis epithelial cell). Although the findings suggest myoepithelial differentiation, the cytogenesis of this tumor remains uncertain.Clear cell sarcoma of kidney (CCSK) is an aggressive childhood renal tumor of unknown histogenesis that has not been reported to occur outside the kidney. The article describes an extrarenal neoplasm arising in the pelvic soft tissues of a 13-year-old boy that was composed predominantly of uniform mesenchymal cells with optically clear cytoplasm supported by an arborizing network of small blood vessels, which was indistinguishable in appearance from CCSK. The electron microscopic findings, although nonspecific, were essentially identical to those of CCSK, with tumor cells displaying fine chromatin, electron-lucent cytoplasm, and intercellular collagen but no evidence of tissue-specific differentiation. Immunocytochemical studies showed positivity for vimentin but negative results for desmin, myoglobin, cytokeratin, epithelial membrane antigen, S-100 protein, neuron-specific enolase and factor VIII-related antigen. Tumor cells were also nonreactive with Ulex lectin. This unusual pelvic tumor and CCSK may both derive from primitive mesenchymal cells and may represent phenotypic but not necessarily histogenetic analogs.

Diagnostic histopathologic criteria in pediatric tumors: An electic review

Malignant tumors of infants and children, unlike their adult counterparts, are commonly undifferentiated or show minimal evidence of differentiation. Because of this, many of these tumors pose a formidable dilemma to the general pathologist in distinguishing one from another. A broad sampling of the more common malignant neoplasms and of newly recognized histologic subtypes which are restricted more or less to the pediatric age group is presented. The minimal microscopic criteria required to establish a diagnosis are given using widely accepted pathologic classifications and seminal journal references as a guide. Ancillary microscopic features, helpful histochemical stains, immunohistochemistry, and ultrastructural morphology are described for most tumors. Histologic distinction from diagnostic mimickers is discussed. Where appropriate, histologic grading and tumor subclassification are presented and their prognostic relevance is reviewed.

BILATERAL NEOPLASTIC KIDNEY DISEASE, PULMONARY CYSTIC DISEASE, AND FETAL MACROSOMIA: A SPECTRUM OF DEVELOPMENTAL ABNORMALITIES

Three similar cases of bilateral neoplastic disease of the kidney were associated with congenital pulmonary cystic disease and fetal macrosomia. These cases are compared to several in the literature. We suggest that these three cases represent a spectrum of abnormal morphogenesis that affects both the kidney and the lung. Case 1 had bilateral multilocular cysts of the kidney in association with hamartomatous pulmonary cysts, This case is compared with Case 2 who had bilateral multilocular renal cysts, with one area of mesoblastic nephroma and multiple pulmonary cysts. These cases are compared to Case 3 who demonstrated markedly hyperplastic renomegaly with medullary dysplasia (similar to what is seen in the Beckwith-Wiedemann syndrome) in association with classical bilateral cystic adenomatoid malformation of the lungs. All three cases were overgrown at birth, and we suggest that these cases illustrate similarities in the development of kidneys and lungs. Embryologically the kidney and lung begin their development around the same time. During the 5th week of gestation, the ureteric bud invades the unsegmented mesoderm that becomes the metanephric system, and the lung bud invades the splanchnic mesoderm which provides the stimulus for its growth. The predominant pattern of a congenital kidney or lung neoplasm may reflect the timing of a prenatal neoplastic event.