Papillary renal cell neoplasm with reverse polarity: A new subtype of renal tumour with favorable prognosis.

INTRODUCTION: Papillary renal cell neoplasm with reverse polarity (PRNRP) has recently been recognized as an entity separate from the traditional classification of papillary renal cell carcinomas, due to its specific histopathological, immunophenotypic and molecular characteristics, as well as its indolent behavior. MATERIAL AND METHODS: We provide 6 new cases and a review of the literature published until the present time, which comprises a total number of 104 cases. RESULTS: Our PRNRP cases correspond to 5 men and one woman aged between 47 and 91 years. In 5 of the 6 cases, the PRNRP was an incidental finding in nephrectomy specimens. Nephrectomy had been indicated due to the presence of another renal tumor, except for one case, in which surgical intervention was indicated due to PRNRP. Our cases present mass sizes between 2 and 13 mm, as well as papillary histology with a monolayered lining of eosinophilic cells with low-grade nuclei in apical location. Immunohistochemically, they show a constant positivity for GATA3 and negativity for vimentin. KRAS mutations were identified in 50% of our cases. After a follow-up ranging between one and 60 months, 5 of the cases were still alive without recurrences or metastases, and one died from urothelial carcinoma. CONCLUSIONS: Our cases agree with the clinical and pathological characteristics described in the PRNRP cases published to date. With the present study, we provide the first series of national cases corroborating the existence of well-defined and constant diagnostic criteria that allow PRNRP to be considered as a distinctive entity.

Usefulness of GATA-3 as a marker of seminal epithelium in prostate biopsies. / Utilidad de GATA-3 como marcador de epitelio seminal en las biopsias de próstata.

OBJECTIVES: The incidental presence of seminal vesicle epithelium in prostate needle biopsies is generally recognisable through routine microscopy. However, the biopsy can sometimes be erroneously interpreted as malignant due to its architectural and cytological characteristics, and immunohistochemistry can be useful for correctly identifying the biopsy. Our objective was to analyse the potential usefulness of GATA-3 as a marker of seminal epithelium. MATERIAL AND METHODS: Through immunohistochemistry with a monoclonal anti-GATA-3 antibody (clone L50-823), we studied seminal vesicle sections from 20 prostatectomy specimens, 12 prostate needle biopsies that contained seminal vesicle tissue and 68 prostate biopsies without seminal vesicle epithelium, 36 of which showed adenocarcinoma. RESULTS: Staining for GATA-3 was intense in the 20 seminal vesicles of the prostatectomy specimens and in the 12 prostate needle biopsies that contained seminal epithelium. In the 60 biopsies without a seminal vesicle, GATA-3 was positive in the prostate basal cells and even in the secretory cells (57 cases), although with less intensity in 55 of the cases. One of the 36 prostatic adenocarcinomas tested positive for GATA-3. CONCLUSIONS: The intense immunohistochemical expression of GATA-3 in the seminal vesicle epithelium can help identify the epithelium in prostate biopsies. This marker is also positive in the basal cells of healthy prostates and, with less intensity, in the secretory cells. Positivity, weak or moderate, is observed on rare occasions in prostatic adenocarcinomas.

[Expresion of E-cadherin and catenins in urothelial carcinomas]. / Expresión de cadherina E y cateninas en los carcinomas uroteliales.

OBJECTIVE: We examined the presence of E-cadherin and alpha, beta and gamma catenins detected by immunohistochemistry and correlated with the classic variables: grade, stage and recurrence. MATERIAL AND METHOD: The authors evaluated 37 transitional cell carcinomas. Biopsy specimens included no recurrent transitional cell carcinoma (n=19) and recurrent transitional cell carcinoma (n=18). Association of E-cadherin and alpha, beta and gamma catenins immunoreactivity with tumor grade, clinical stage and tumor recurrence was examined. RESULTS: E-cadherin and gamma catenin expression were related to the clinical stage of the disease, alpha and beta catenins were not correlated with grade, stage and recurrence of disease. CONCLUSIONS: Decreased E cadherin and gamma catenin expression were associated with advanced stage of the disease.

[Expression of cytokeratin 5 and calretinin in clear-cell renal cell carcinoma]. / Expresión de citoqueratina 5 y calretinina en el carcinoma renal de células claras.

PURPOSE: Cytokeratin 5 (CK5) and calretinin have been useful in different studies as immunohistochemical markers suggestive of mesothelioma, and their expression is analyzed for the histological differential diagnosis with adenocarcinomas, specially when confronting with metastatic tumors of unknown origin. We have analyzed the expression of CK5 and calretinin in clear cell renal cell carcinoma. METHODS: A series of 63 clear cell renal cell carcinomas was studied. 46 of these cases were embedded in two tissue arrays, and a second group, of 17 cases, was constituted by conventional paraffin blocks from high-grade tumors (grade 4 of Fuhrman). Immunohistochemical staining was performed with monoclonal antibodies against CK5 and calretinin, following the labeled sptreptavidin-biotin technique. RESULTS: No positivity for calretinin was observed in any case, while CK5 was focally expressed, in an isolated group of cells, in 1 of the 63 cases (1,59%) which corresponded to a high-grade carcinoma (grade 4 of Fuhrman). CONCLUSIONS: Expression of calretinin was not observed in clear cell renal cell carcinoma and positivity for CK5 occurred only in one case, in a very small proportion of tumor cells. Therefore, in practice, although the positivity for these markers cannot completely exclude renal cell carcinoma, this result is very rare in this tumor and other diagnostic posibilities should be considered.

[Expression of CD10 and renal cell carcinoma marker in clear cell renal cell carcinoma: analysis on tissue arrays]. / Expresión de CD10 y del marcador de carcinoma renal en el carcinoma renal de células claras: análisis en matrices tisulares.

OBJECTIVES: CD10 and renal cell carcinoma (RCC) marker antibodies react against proteins of the epithelium of the renal proximal tubule, being expressed by renal cell carcinomas. The frequence and pattern of expression of both markers are analysed in a series of clear cell renal cell carcinomas. METHOD: Two tissue arrays were used, which were composed of cylinders obtained with a 16G needle from 40 paraffin blocks that corresponded to clear cell renal cell carcinomas. The labeled streptavidin-biotin technique was performed (LSAB2, Dako) using CD10 and RCC monoclonal antibodies (Novocastra), testing different antigen retrieval methods for RCC. Immunoreactivity was evaluated as + (isolated cells or focal staining); ++ (moderate) and +++ (extense). RESULTS: Thirty cases (75%) were positive for CD10: 12 +; 5 ++ and 13 +++. The best antigen retrieval method for RCC was a double enzyme digestion (trypsin + protease). Twenty cases (50%) were positive for RCC: 7 +; 5 ++ and 8 +++. Four cases out of the 20 immunoreactive for RCC were negative for CD10. The 16 remaining cases also expressed CD10. CONCLUSIONS: CD10 and RCC are often expressed by clear cell renal cell carcinomas, and they may be useful markers to suggest a renal origin of carcinomas. RCC is less sensitive than CD10. Staining for both of them is usually focal, and thus sensitivity of these techniques decreases when small samples are investigated, such as tissue arrays. The antigen retrieval method is essential for RCC immunohistochemical detection, obtaining the best results with the use of proteolytic enzymes.