Antigen immunohistochemistry of renal cell adenomas in autopsy cases: relevance to histogenesis

Papillary Renal Adenoma of Distal Nephron Differentiation in a Horse

A 20-year-old thoroughbred mare had a mass in the right kidney. The mass was encapsulated with fibrous capsule and composed of variably-sized papillary projections lined by a single layer of flattened to cuboidal neoplastic epithelial cells with no cytological and nuclear atypia. Immunohistochemically, the neoplastic cells were broadly positive for cytokeratin AE1/AE3 and granular staining for alpha-1-antitrypsin was focally detected; this immunohistochemical property was similar to that of the normal distal nephron. From these results, this case was diagnosed as papillary renal adenoma of distal nephron differentiation.

Histogenesis of the acquired cystic kidney disease: an immunohistochemical study

The aim of this study was to characterize by immunohistochemistry the histogenesis of cysts in acquired cystic kidney disease (ACKD). Thirty renal tissues fixed in 10% formalin and embedded in paraffin from 20 cases of ACKD were studied. Vimentin was used to stain the Bowman's capsule epithelium, Lotus tetragonolobus agglutinin (LTA) and Leu M1 (CD15) for proximal tubules; Tamm-Horsfall protein (THP) for distal tubules; epithelial membrane antigen (EMA), cytokeratin 19 (CK19), Arachis hypogea agglutinin (PNA), and Glycine maximum agglutinin (SBA) for distal tubules and collecting ducts; and Ulex europaeus agglutinin (UEA-I) and Dolichos biflorus agglutinin (DBA) for collecting ducts. A histologically normal kidney, free of cystic disease, was used as a control for all the markers. Most of the cysts showed strong reactivity to LTA and CD15, an immunophenotype more characteristic of proximal tubules.

Histogenesis of human renal cell carcinoma by using electron microscopy and immunohistochemical techniques

Electron microscopy and immunohistochemical techniques are powerful tools for the determination of tissue origin. Both techniques have been used in the current experiment for histogenesis of renal cell carcinoma. Fifty kidney tumors were subjected to immunohistochemical detection for intermediate filaments cytokeratin and vimentin, which are normally expressed in epithelial tissue and mesenchymal tissues, respectively. Twenty cases of the above were examined by electron microscopy for detection of ultrastructure features. From each kidney, two specimens were taken, one from the diseased area and another far from it to serve as a control. Immunohistochemical study revealed in cases of renal cell carcinoma, cytokeratin and vimentin were expressed alone in 44% of cases, and 40% of cases, respectively. Twelve percent of cases were coexpressed with both cytokeratin and vimentin. Electron microscopic study of diseased specimens revealed the expression of desmosomes which was observed in almost all tumor specimens. The expression of the vimentin in some cases either alone or with cytokeratin was interpreted as a change in the characters of some tumor cells which indicates the need for additional techniques in such cases to get the proper interpretation. The prevalence of the expression of cytokeratin and the persistence existence of desmosomes indicate the epithelial origin of the tumor. This data is very beneficial for determination of line of therapy and follow up of the patients. The results confirm the power of combined use of both immunohistochemistry and electron microscopy in the field of histogenesis.

Multicentric papillary renal cell carcinoma associated with renal adenomatosis

A case of multicentric papillary renal cell carcinoma (RCC) associated with renal adenomatosis in the bilateral kidneys is reported. Bilateral multiple renal cysts in a 46-year-old man were pointed out incidentally by ultrasonography. Some of the left renal lesions were considered to be RCC, and left radical nephrectomy was performed accordingly. The left kidney was occupied by numerous solid nodules, which ranged from yellow to tan in color, and some of the large ones had foci of hemorrhage and necrosis. Microscopically, most of the tumors showed papillary RCC associated with renal adenoma, while others consisted only of adenomas. Ten months later, multiple lesions of the right kidney, which were initially considered to be multiple cysts, were found to have become enlarged and some of them were diagnosed as RCC. Thus, right radical nephrectomy was also performed, and these tumors showed the same features as the left renal tumors. The patient's familial history was not remarkable. The kidneys revealed various histological features, ranging from dysplastic to adenoma or carcinoma, including transitional or overlapping features between them. The findings suggest an adenoma-carcinoma sequence in papillary RCC. It is worth considering such entities.

Subclassification of renal cell neoplasms: an update for the practising pathologist

The classification of renal cell neoplasms has been extensively studied in the last decade, and a standardized nomenclature adopted. Although this system is based on a combination of genetic, histological and immunohistological features, in most cases accurate classification can be based on histological features alone. This review summarizes the key features of the tumours included in this system, and then focuses on diagnostic difficulties that can arise when using this system, as well as reviewing several recently characterized tumours that are not yet included.

Analysis of multiple renal cell adenomas and carcinomas suggests allelic loss at 3p21 to be a prerequisite for malignant development

Multiple renal cell tumours from three unrelated patients have been analysed for loss of heterozygosity of 3p, mutation of VHL, and chromosome 7 and 17 imbalances. Loss of 3p alleles is characteristic for clear cell type tumours and the combination of +7, +17 for chromophilic cell type tumours. Thus, we could classify adenomas and carcinomas of the three patients according to the genomic patterns of the tumours. Adenomas appeared to be mostly of the chromophilic cell type. In some adenomas, however, allelic losses of chromosome 3 were detected, pointing to a clear cell phenotype. Irrespective of showing loss or retention of the 3p25 region, none of the adenomas had a VHL mutation. Therefore, inactivation of VHL does not seem to be an early event in the development of renal cell tumours. Results of an analysis of regions of loss and retention of alleles of 3p markers in multiple tumours of the individual patients suggest that losses at either 3p25 or 3p12-p14 are associated with adenomas. Additional loss at 3p21 is most likely required to lead to development of a more malignant clear cell carcinoma.