[Wilms tumor as a novel model of angiogenesis in childood nephropathies]. / Guz Wilmsa jako model angiogenezy w nefropatiach wieku mlodzienczego.

Wilms tumor has a unique possibility of recapitulation within its substance different stages of renal development. Vascular endothelial growth factor (VEGF) and its receptors (VEGFR-1 and VEGFR-2) are regarded to play the crucial role in the process of simultaneous development of tubules and glomeruli in animal kidney. Neoangiogenesis, secondary to rearrangement of epithelial elements in Wilms tumor, may therefore follow the lack of glomeruli in this neoplasm. The aim of the present research was an immunohistochemical analysis of VEGF-C and VEGFR-2 expressions in Wilms tumor and an attempt of explanation of neovascularisation process in this malignancy. The study group was composed of 16 children diagnosed with Wilms tumor (stage III of clinical classification) hospitalised in Department of Paediatric Oncology, Hematology and Transplantology, University of Medical Sciences in Poznan. The indirect immunohistochemical assay with the use of monoclonal antibodies directed against VEGF-C and VEGFR-2 was employed. VEGF-C expression was detected within blastemal and hypocellular stromal components of Wilms tumor. On the other hand, immuno-reactivity of VEGFR-2 was established in dysplastic tubules in the closest proximity of VEGF-C positive parts of stromal origin. VEGF-C dependent neovascularisation in Wilms tumor may follow an adequate differentiation of already existing epithelial elements. It may also explain the process of glomeruli-dependent physiological development of kidney and, what is also probable, the phenomenon of neoangiogenesis described in individual childhood nephropathies.

Intralobar nephroblastematosis: precursor lesions of nephroblastoma in the Sprague-Dawley rat.

Precursor lesions of spontaneous nephroblastoma (NB) in rats are here characterized for the first time, with a description of the progression of the tumor in prenatal, postnatal, and adult Sprague-Dawley rats (Upj:TUC[SD]spf.nb), which are genetically predisposed to the tumor. NB in the rat starts as a focal or multifocal interstitial accumulation of intensely basophilic immature (blastema) cells, invariably located in the deep renal cortex. Precursor lesions of NB (designated intralobar nephroblastematosis) and the early tumor do not overtly disrupt the overall structural organization and integrity of the kidney. However, with increasing size and neoplastic transformation, these lesions trap, compress, and displace/replace the existing renal tubules. Nephroblastematous foci occurred in one or both kidneys in tumor-bearing or non-tumor-bearing kidneys and in young and old rats. Like the precursor lesions, the early tumors in rats as young as 6 weeks of age were located in the inner cortex. Well-developed NB was comprised of blastema cells arranged in dense sheets or in ductular structures surrounded by mantles of blastema cells supported by varying amounts of fibromatous stroma. The stroma in one rat was hemangiosarcomatous (triphasic Wilms' tumor). Tumor cells were slightly pleomorphic and had varying amounts of granular cytoplasm with sparse organelles and showed junctional complexes and basal laminae whose frequency apparently depended upon whether the blastema cell tended to differentiate to epithelial or mesenchymal cells. NB in the rat was morphologically similar to immature pre- and postnatal kidneys, regardless of whether it occurred in young or old rats. The deep cortical location and interstitial infiltrative characteristics of precursor lesions of NB in the rat were analogous to intralobar nephrogenic rests, a variant of the precursor to Wilms' tumor in children.

Cystic partially differentiated nephroblastoma in an adult: an immunohistochemical, lectin histochemical and ultrastructural study.

AIMS: Cystic partially differentiated nephroblastoma (CPDN) is an uncommon renal multicystic tumour, usually affecting early infants. To our knowledge, this report describes the first case of CPDN occurring in an adult. METHODS AND RESULTS: A 45-year-old man was found incidentally to have a left renal cystic tumour, measuring 20 mm in diameter, at the lower pole far from the pelvis. The tumour was composed of multilocular cystic spaces of variable size and intervening septa without solid nodular areas. The cysts were lined by a single layer of flattened, hobnail, or columnar epithelium. The septa were made of mesenchymal cells, which were admixed with small numbers of loosely aggregated blastemal cells, occasional tubular structures in various stages of development, and a few glomeruloid structures. The tumour cells had no anaplasia, and mitoses were rare. Immunohistochemical and lectin histochemical studies revealed that the cyst lining epithelium and the tubular structures in the septa expressed predominantly the markers for distal tubules and collecting ducts. Ultrastructurally, the cyst lining cells closely resembled collecting duct cells while some tubular structures showed an immature nephrogenic morphology. The patient was alive and well without evidence of recurrence 11 months after surgery. CONCLUSIONS: CPDN does occur in adults, as experienced in Wilms' tumour, though its incidence is extremely low. This study suggests that CPDN may show maturation intermediate between cystic nephroma and Wilms' tumour, even in adult cases.

Extensively cystic renal neoplasms: cystic nephroma, cystic partially differentiated nephroblastoma, multilocular cystic renal cell carcinoma, and cystic hamartoma of renal pelvis.

Predominantly cystic renal neoplasms have been the source of diagnostic confusion and controversy. In this review, the authors analyze the clinical and pathological features of four entities that consistently exhibit a diffusely cystic growth pattern, are strikingly similar in their gross appearances, and are not separable by preoperative imaging studies. Based on the literature, this review concludes that tumors in young children that have been classified as cystic nephroma and cystic partially differentiated nephroblastoma likely represent a single entity, and all should be considered highly cystic Wilms' tumors with little or no capacity for invasion or metastasis and diagnosed as cystic partially differentiated nephroblastoma. Conversely, cystic nephroma in adults has no discernible connection with Wilms' tumor or nephrogenic rests and should be considered a benign composite neoplasm of stroma and epithelium of unknown histogenesis, which may rarely become malignant with secondary development of a sarcoma. Multilocular cystic renal cell carcinoma appears to be unrelated to cystic nephroma and if the following criteria are met, it appears to be a neoplasm with an intrinsically cystic growth pattern, and no, or at most little, malignant potential: (1) an expansile mass is surrounded by a fibrous wall, (2) the interior of the tumor entirely is composed of cysts and septa with no expansile solid nodules, and (3) the septa contain aggregates of epithelial cells with clear cytoplasm. Cystic hamartoma of the renal pelvis is a rare, complex tumor composed of stroma with a prominent smooth muscle component and a variety of epithelial elements.

Appraisal of the comparative utility of immunohistochemistry and electron microscopy in the diagnosis of childhood round cell tumors.

To provide an objective assessment of the comparative utility of fluorescence- and peroxidase-based immunohistochemistry and electron microscopy, an observer blinded study was conducted under realistic study conditions utilizing a large sampling of poorly differentiated pediatric round cell tumors. Working independently, using a single ancillary technique of particular expertise, each of three investigators attempted to render a specific diagnosis with regard to 50 diagnostically challenging tumors. The results were compared against the subsequent "file diagnosis" established by consensus with all relevant information made available. A grading scheme was applied wherein points were awarded based on the accuracy and confidence of diagnosis. A comparative efficiency rating, expressed as a percentage, was formulated by dividing the number of points awarded each technique by the total number of points theoretically available. Electron microscopy proved superior overall, with an efficiency rating of 89%. Immunoperoxidase and immunofluorescence studies yielded efficiency ratings of 71 and 61%, respectively. Used in combination, the techniques achieved an efficiency rating of 95%. Application of these ancillary techniques resulted in a revision of the provisional diagnosis in 11 of 50 cases, and left only two cases without a firm specific diagnosis.

[Multicystic renal dysplasia and Wilms tumor]. / Displasia renal multiquística y tumor de Wilms.

We review a case of multicystic right dysplasia containing nodular renal blastema in a 3-year-old girl with left Wilms tumor. In relation to this finding the management of the asymptomatic multicystic dysplastic kidney in discussed.

Extrarenal Wilms' tumor: an ultrastructural and immunoelectron microscopic case report.

Wilms' tumor is the most common malignancy of the genitourinary tract in children but the occurrence of extrarenal Wilms' tumor is extremely rare. Extrarenal Wilms' tumor, which by definition excludes a primary tumor in the kidney, has been reported less than fifty times. The ultrastructural appearance of renal Wilms' tumor has been well documented, but the present report is believed to be the first description of the ultrastructural appearance of extrarenal Wilms' tumor. The authors report, for the first time, localization of intermediate filament proteins (vimentin and cytokeratin) and epithelial membrane antigen (EMA) by immunoelectron microscopy in this neoplasm. Demonstration of the coexpression of vimentin and cytokeratin within the same blastemal cell, as well as the identification of desmosomes in a cell with vimentin intermediate filaments, suggests a relationship between stroma, blastema, and epithelia similar to that proposed in renal Wilms' tumor.

Role of immunocytochemistry, electron microscopy, and DNA analysis in fine-needle aspiration biopsy diagnosis of Wilms' tumor.

We reviewed the cytologic features and results of ancillary studies in eight fine-needle aspiration biopsies (FNAB) performed by posterior approach in 8 patients with unresectable Wilms' tumor (WT). Chemotherapy was given following the FNAB diagnosis of WT, which was confirmed subsequently by histologic examination of surgically resected specimens. Indications for FNAB included: unresectable tumor, bilateral disease, initial presentation with metastatic disease, uncertainty regarding tumor site, and documentation of recurrence. Cytologic examination revealed blastemal cells (8/8 aspirates), spindle cells (3/8 aspirates), and epithelial differentiation or tubules (3/8 aspirates). There was no cytologic evidence of anaplasia in any of the cases. Immunocytochemical studies on cell blocks and/or smears showed cytokeratin positivity in 5/8 and vimentin positivity in 5/5 of the aspirates in which these studies were performed. Focal positivity for neuron-specific enolase (NSE) was seen in 3/3 aspirates. Stains for actin and leukocyte-common antigen were negative (0/3 and 0/2 aspirates, respectively). DNA ploidy analysis of the aspiration material by flow cytometry revealed near-diploid populations in three aspirates. Electron microscopic findings helpful for diagnosis included: cell junctions, microvilli, flocculent basement membrane-like material, cilia, autophagolysosomes, and lack of neuroectodermal differentiation. Diagnostic morphologic pitfalls for an incorrect diagnosis of neuroblastoma included nuclear molding (all aspirates), pseudorosette formation (one aspirate), and focal NSE positivity (3/3 aspirates). None of the tumors showed anaplasia on histologic examination. Cytologic recognition of the triphasic cellular components of WT (blastemal cells, spindle cells, and epithelial cells) can be helpful for a correct diagnosis; however, in 5/8 aspirates in this study, only the blastemal component was present. In these cases, immunocytochemical stains and electron microscopy proved useful in arriving at a correct FNAB diagnosis of WT. However, NSE positivity can be a pitfall for a diagnosis of neuroblastoma if the radiologic, clinical, and other cytologic features are not clearly delineated. Presence of cytokeratin and vimentin positivity would be helpful in the diagnosis of WT in such instances.

Isochromosome 7q in adult Wilms' tumor.

We describe cytogenetic and histologic findings in a Wilms' tumor resected from a 37-year-old man. The tumor karyotype was 45,X,-Y,i(7)(q10). These findings are notable because overrepresentation of chromosome 7 long arm material, i(7)(q10) in particular, has been described recently as a nonrandom event in pediatric Wilms' tumors. The present case suggests a shared genetic pathway in the initiation or progression of some pediatric and adult Wilms' tumors.

A nude mouse Wilms' tumor line (KCMC-WT-1) derived from an aniridia patient with monoalleleic partial deletion of chromosome 11p.

BACKGROUND: A candidate tumor suppressor gene, WT-1, is believed to have an important role in the pathogenesis of Wilms' tumor, especially that occurring in patients with congenital aniridia. METHODS: To obtain a stable tumor line to work with, Wilms' tumor tissue was serially transplanted in athymic nude mice. Biopsied Wilms' tumor tissue, derived from an aniridia patient, was transplanted subcutaneously to an athymic nude mouse, and then transplanted serially. Histopathologic and molecular biologic studies were performed on the xenotransplants. RESULTS: The aniridia patient showed partial deletion in one short arm of chromosome 11, which bears the WT-1 gene. The tumor was successfully transplanted in the nude mouse. Although the tumor contained blastemic, organoid, and stromal histologic elements, the organoid element began to decrease after more than 20 passages. Cytogenetic analysis revealed an additional abbreviation of one long arm of chromosome 6. Dot blot analysis showed that the copy number of WT-1 gene was decreased to half the amount in the tumor, in spite of the WT-1 transcript with normal size detected by Northern blotting. CONCLUSIONS: The tumor is expected to bear one WT-1 gene with minute abnormalities as well as one congenitally deleted gene. This tumor line is useful when examining the effect caused by introduction of WT-1 gene to Wilms' tumor in vivo.

Establishment and characterization of a cell line (NB-YK) derived from a transplantable rat nephroblastoma.

A new cell line, designated NB-YK, was established from a transplantable rat nephroblastoma (NB-Y) which was derived from a spontaneous nephroblastoma in an aged Fischer 344 rat. NB-YK grew in a piling-up and noncohesive pattern on the plastic surface and formed colonies in a soft agar. The main cell type of NB-YK represented morphology of mesenchymal phenotype and most of the cells contained several secretory granules in their cytoplasm. Immunocytochemically the cells were positive for vimentin, cytokeratin, and laminin. Coexpression of vimentin and cytokeratin in the cells was confirmed by the one-dimensional gel electrophoresis and immunoblotting for intermediate filament proteins. NB-YK cells were tumorigenic and produced fibrosarcoma-like tumor when inoculated subcutaneously or intraperitoneally into syngeneic rats and nude mice. NB-YK seems to be a useful model for studying biological properties of nephroblastoma.

Prediction of disease-free survival after therapy in Wilms' tumor using nuclear morphometric techniques.

The outlook for children with Wilms' tumor has markedly improved with the use of multimodal therapy, and survival currently exceed 85%. Current trends have been to use less intense therapy for children whose tumors have favorable histology (FH). By decreasing the amount of therapy given to patients whose conditions have an excellent chance of responding, the need for accurate criteria to separate high-risk and low-risk groups becomes imperative. Nuclear morphometric techniques have been developed and extensively tested in the author's laboratory. Preliminary studies of FH Wilms' tumors demonstrated the applicability of this technique. Herein, the authors present a retrospective study of 108 patients with FH tumors, with a mean follow-up period of 1,994 +/- 107 days (66 months) for those whose tumors did respond to therapy, and 686 +/- 61 days (23 months) for those whose tumors did not respond. The univariate predictors were age (P = .02), the skewness of nuclear roundness factor (SNRF) (P = .009), and the mean of the lower five values for nuclear ellipticity, measured by the feret diameter method (L5EFD) (P = .01). A multivariate analysis combining all three variables better separated the two groups (P = .00016). A probability function curve was constructed to predict poor prognosis. Kaplan-Meier actuarial survival analysis was used to predict disease-free survival as clinical progression, and separated the two groups (P = .0004, Wilcoxon-Gehan statistic). These results suggest that nuclear morphometry is useful in the initial assessment of patients with Wilms' tumor.

Mesoblastic nephroma of adulthood. Report of three cases.

Mesoblastic nephroma is an uncommon congenital tumor of infancy that rarely occurs in adults. We report three patients (two were female, one was male) who had mesoblastic nephroma of adulthood and who presented at 45, 64, and 66 years of age with hematuria, flank mass, and pain. All underwent nephrectomy without postoperative adjuvant therapy. The tumors were solitary yellow-tan masses with solid and cystic areas involving the renal cortex (three cases) with extension into the renal pelvis and calyces (two) and ureter (one). Microscopically, all consisted of uniform spindle cell proliferations with entrapped dilated renal tubules. Focal necrosis was present in two, but no atypia or mitoses were identified in any case. The spindle cells displayed cytoplasmic immunoreactivity for vimentin, desmin, panmuscle actin (HHF-35), and alpha-smooth-muscle actin, but were nonreactive for keratin (AE1/AE3), epithelial membrane antigen, and S-100 protein. Electron microscopy revealed the presence of smooth-muscle differentiation in two cases and undifferentiated mesenchyme in one. All tumors were DNA diploid by flow cytometry. The patients were free of recurrence 8 months-2 years postoperatively. Because surgical excision may be curative, mesoblastic nephroma in adult patients must be differentiated from spindle cell neoplasms of the kidney that require additional therapy.

Aspiration cytology of Wilms' tumor.

We reviewed the cytomorphologic features of fine needle aspiration biopsy (FNAB) smears from 15 cases of renal, extrarenal and metastatic Wilms' tumor. The findings were correlated with the histopathologic features. In cytology smears, blastemal cells were recognized in all cases. The following cell types were seen: epithelial cells, 60%; stromal component, 33.3%; tubular differentiation, 26.6%; and glomeruloid differentiation, 33.3%. FNAB smears of the metastatic lesions in the liver and of the primary lesions did not reveal any significant difference in cellular composition. Subcutaneous soft tissue metastasis from an anaplastic Wilms' tumor showed marked anaplasia and pleomorphism of blastemal cells along with frequent mitosis and bizarre tumor giant cells. Extrarenal Wilms' tumor showed only blastemal cells, though histopathology showed the classic triphasic pattern along with skeletal muscle differentiation. There were no complications attributable to the procedure. Recognition of these cellular components in FNAB smears will help in establishing an FNAB diagnosis of Wilms' tumor, particularly when preoperative chemotherapy is needed.

Morphology and growth characteristics of epithelial cells from classic Wilms' tumors.

The ability to establish cell cultures representing the epithelial component of Wilms' tumor was determined for 18 cases of classic Wilms' tumors. From these 18 cases only two resulted in the culture of epithelial cells. Although the tumors from both cases were composed of a prominent epithelial component, other classic tumors not producing epithelial cell cultures also possessed appreciable epithelial components. Likewise, heterotransplants of these two primary tumors failed to give rise to epithelial cell cultures, although cultures of the blastemal element were produced. This suggests that Wilms' tumors may be prone to differentiate in different directions at varying times during tumor growth, possibly dependent on local tumor environment. Epithelial cells from these two classic cases were grown in culture in basal medium composed of a 1:1 mixture of Dulbecco's modified Eagle's medium and Ham's F-12 medium, supplemented with selenium, insulin, transferrin, hydrocortisone, tri-iodothyronine, and epidermal growth factor, on a collagen type I matrix with absorbed fetal calf serum proteins. One of the two cases also required the addition of bovine pituitary extract, ethanolamine, prostaglandin E1, and putrescine for optimum growth. Morphological analysis disclosed that the cultured cells were very similar to normal renal tubular cells in culture, except that the cells displayed little evidence for differentiated active ion transport and tended to grow in a multilayered arrangement. The culture of the epithelial cells from classic Wilms' tumors provides a model system for the study of tumor differentiation and progression.

The use of nuclear morphometry to predict prognosis in pediatric urologic malignancies: a review.

Wilms tumor, the most common pediatric urologic malignancy, and genitourinary rhabdomyosarcoma, the most common soft tissue sarcoma of childhood, represent two of the most commonly diagnosed pediatric urologic malignancies. The introduction and use of multimodal therapy (surgery, radiation, and chemotherapy) by the National Wilms Tumor Study (NWTS) and the Intergroup Rhabdomyosarcoma Study (IRS) groups have greatly improved the survival among children with these malignancies. Present survival rates for Wilms tumor exceed 85% and for rhabdomyosarcoma survival rates are approaching 80% as well. For Wilms tumor, current treatment trends suggest less intense therapy for those children with favorable histology tumors who are considered at relatively low risk for tumor recurrence. Likewise, the significant morbidity associated with the present therapy regimens for rhabdomyosarcomas has prompted investigators to search for individualized management schemes for children with a high probability of responding. The need for accurate criteria to separate these high and low risk groups becomes imperative. In this review we present our work using nuclear morphometry, as a prognostic indicator, to retrospectively predict response to therapy for children with Wilms tumors and genitourinary rhabdomyosarcomas.

Adenomyoepithelioma of the breast: fine-needle sampling with histologic, immunohistologic, and electron microscopic analysis.

Fine-needle sampling was performed in a woman with a subareolar breast mass. The cytologic diagnosis was consistent with a benign sweat gland-type tumor. Cytologic features included epithelial cells and spindle-shaped cells lying free or in fibrillary myxoid ground substance. Histologic study revealed the biphasic appearance of this tumor composed of proliferating myoepithelial cells and glandular epithelial cells as supported by immunohistologic and electron microscopic analyses. Epithelial cells were strongly positive for cytokeratins, and spindle cells were positive for actin, S-100 protein, and keratin and showed ultrastructurally typical features of myoepithelial cells.

Preoperative chemotherapy of cellular congenital mesoblastic nephroma in a 5-month-old infant.

Cellular (or atypical) congenital mesoblastic nephroma (CMN) is a potentially aggressive form of the benign classical congenital mesoblastic nephroma. We report here a case of cellular CMN in a 5-month-old boy treated preoperatively with chemotherapy with an excellent response allowing a complete surgical resection.

Incidence, histopathologic and electron microscopic features of spontaneous nephroblastomas in rats.

Primary renal neoplasms in the rats are uncommon. Nephroblastoma is the only renal embryonal tumor of the rat; all other tumors are reported in older rats. The occurrence of spontaneous nephroblastoma in rats has been reported. However, metastasis from the nephroblastoma in rat is extremely rare. Data from 2669 Sprague-Dawley control rats and 1060 Fischer-344 rats were reviewed and evaluated to determine the incidence and pathology of nephroblastoma. This tumor was observed in three Sprague-Dawley rats. Metastasis was observed in the lungs and renal lymph nodes in two different rats. No case of nephroblastoma was observed in Fischer-344 rats. Detailed histopathological and electron microscopic features of these neoplasms are described and discussed.

Ultrastructural study of foetal and adult mouse renal tissue implanted in testis.

Kidneys of mice foetuses 15, 17, 19 days old, as well as kidneys of mice 1 and 4 weeks old of the pure C3H/SY species, were implanted into the right testis of 40 adult mice 1.5 to 2 months old, of the same species. The animals were sacrificed after 30 and 60 days and the evolution and development of the renal implants within the testis ware studied. The findings in the light as well as in the electron microscope, showed that the renal implants presented the histologic characters of nephroblastoma, which became clearer the more prolonged the time of the implantation was.