Chromophobe renal cell carcinoma

Oncocytic mania: a review of oncocytic lesions throughout the body

Oncocytic lesions are characterized pathologically by an abundance of oncocytes, that is by enlarged, eosinophilic, and finely granular cells enriched in mitochondria. They can arise in numerous organs and tissues, often in endocrine glands, and have been associated with hyperplasia, autoimmunity, and neoplasia. The causes and mechanisms that transform a normal cell into an oncocyte remain to be elucidated. Aim of this article is to review the most common oncocytic lesions, highlighting their key pathological features and clinical significance.

Upregulated IL-18 expression in type 2 diabetic subjects with nephropathy: TGF-beta1 enhanced IL-18 expression in human renal proximal tubular epithelial cells

AIM

In order to clarify the importance of Interleukin (IL)-18 in the development of diabetic nephropathy (DN), we evaluated the expressions of IL-18 in diabetic kidney.

METHODS

We performed immmunohistochemical analysis of IL-18 and IL-18 receptor (IL-18 R) in human kidney tissue derived from 12 subjects with type 2 diabetes and overt nephropathy, and compared with those in 7 subjects with minimal change nephrotic syndrome (MCNS). In addition, we examined the regulation of IL-18 expression using human renal proximal tubular epithelial cells (HRPTECs) in culture.

RESULTS

IL-18 expression in tubular cells was observed in higher rate (83%) in patients with diabetes, whereas one positive specimen (14.3%) for IL-18 in patients with MCNS. In contrast, IL-18 R was expressed in glomerular mesangial cells and endothelial cells as well as tubular cells, similarly in almost of both groups. Exposure to transforming growth factor beta (TGF-beta(1)) led to two-fold increase in IL-18 gene expression in HRPTECs, and mitogen-activated protein kinases (MAPK) inhibitors abolished TGF-beta(1)-induced IL-18 mRNA expression. Western blot analysis showed the IL-18 protein in HRPTECs.

CONCLUSION

The present data indicate that IL-18 is overexpressed in human tubular epithelial cells in diabetic nephropathy, probably through the activation of MAPK pathways induced by TGF-beta(1).

Chromophobe renal cell carcinoma showing oncocytoma-like hyalinized and edematous stroma: A case report and review of the literature

A case of chromophobe renal cell carcinoma (CRCC) with abundant hyalinized and edematous stroma mimicking oncocytoma is presented. This stromal architecture in the current case has not been reported on CRCC to our knowledge. A further interesting finding is entrapped non-neoplastic tubules in the hyalinized and edematous stroma composing the tumor. These histological features, such as abundant hyalinized and edematous stroma containing non-neoplastic tubules, may be analogous to oncocytoma. We reported a unique case of CRCC and studied with light microscopy and immunohistochemistry.

Multilocular cystic renal cell carcinoma: a clinicopathological, immuno- and lectin histochemical study of nine cases

Multilocular cystic renal cell carcinoma (MCRCC) is an uncommon variant of renal neoplasm and its histogenesis is unclear. The aim of this study was to use immuno- and lectin histochemistry to delineate histochemical patterns which might indicate the histogenetic origin of MCRCC from a particular part or parts of the nephron. We present our experience with nine cases of MCRCC. Fifteen cases of renal cell carcinoma with cystic degeneration (RCC-CD) were selected for comparison with MCRCC. We carried out clinicopathological and immunohistochemical examinations of the MCRCC cases. Clinically, the prognosis of the patients was quite good, in that all nine patients are alive and without recurrence at the time of this report. The MCRCCs reacted strongly in a higher proportion of cases with the distal nephron markers, such as peanut agglutinin (PNA, 88.9%) and MUC1-core antibody (MUC1, 100%), but none reacted preferentially with proximal nephron markers such as vimentin, Leu M1 and Lotus tetragonolobus (LTA). The RCC-CD tumours reacted with vimentin (40%), Leu M1 (66.7%) and LTA (86.7%). Except for two cases, the RCC-CD tumours did not react with PNA or MUC1 core antibody. These results illustrate the different patterns of expression of MCRCC and RCC-CD and suggest that MCRCC originates from the distal nephron. Therefore, MCRCC should be differentiated from other types of renal cell carcinoma on the basis of the histogenesis of the tumour and the clinicopathological findings.

Chromophobe renal cell carcinoma: clinical, pathological and molecular biological aspects

Chromophobe renal cell carcinoma (RCC), a newly established subtype of renal neoplasm, is composed of tumor cells with characteristically cloudy, weakly eosinophilic and reticular cytoplasm. The tumor should be distinguished from the common clear cell RCC, because of the unique clinicopathological and molecular biological features. The tumor does not show gender bias. Patient ages are similar to those of clear cell RCC, but might occur in the 20- to 40-year-old age group. Grossly, the tumor tends to be beige in color, which is different from the yellowish color of common RCC. Electron microscopy and immunohistochemistry indicate the intercalated cell of the collecting duct as the cellular origin. Cytogenetic study shows non-random multiple chromosome loss, with mitochondrial DNA rearrangement. Alteration of the von Hippel-Lindau (VHL) gene, a cancer suppressor gene relating with clear cell RCC, has not yet been observed. In order to adopt the most appropriate treatment, including gene therapy, recognition and correct pathological diagnosis of chromophobe RCC are extremely important.

Pigmented microcystic chromophobe cell carcinoma: a unique variant of renal cell carcinoma

Five cases of pigmented chromophobe renal cell carcinoma are presented. The patients included four men and one woman between the ages of 60 and 73 years (median age, 66.5 years), who presented with symptoms due to their renal mass. Surgical resection of the renal mass was performed in all patients. Grossly, the tumors were well encapsulated, yellow to dark gray, with a vague nodular pattern on cut surface. The tumors varied between 2.5 and 9 cm in greatest diameter. Histologically, all tumors shared similar features, namely, a malignant cellular proliferation composed of deeply eosinophilic to clear cytoplasm with round nuclei and inconspicuous nucleoli. The cellular proliferation was arranged in a microcystic and/or microalveolar pattern. In one tumor, conventional areas of clear cell carcinoma in association with the chromophobe component were present. In addition, all tumors contained pigmented areas, which were shown by light microscopy to have features of lipochrome pigment. Ultrastructural studies of these areas demonstrated the presence of intracytoplasmic polygonal to round, electron-dense pigment granules, which in some areas seemed to coalesce to form larger granules. In addition, numerous mitochondria and cytoplasmic vesicles were present. The cases described herein highlight an additional morphologic variant of chromophobe renal cell carcinoma.

Sarcomatoid renal cell carcinoma: the chromophobe connection

Eleven cases of sarcomatoid renal cell carcinoma were studied to determine the relative frequency of various subtypes of renal cell carcinoma that may be associated with sarcomatoid transformation. The epithelial components in these tumors were subcategorized according to established histologic criteria into chromophobe carcinoma (n = 6 cases), clear cell carcinoma (n = 3), papillary carcinoma (n = 1), and indeterminate (n = 1). In nine cases, material was available for immunohistochemical and DNA ploidy studies. The sarcomatoid component in all cases showed positivity for epithelial membrane antigen cytokeratin, indicating an epithelial derivation of these cells. Staining for mesenchymal markers was mostly negative, except for vimentin, which reacted strongly in all cases. DNA ploidy studies using flow cytometry and cell image analysis provided very similar results. Five of five chromophobe sarcomatoid carcinomas showed hypodiploid cell lines in the epithelial areas, whereas the sarcomatoid components mostly showed aneuploid peaks. In the remaining cases, DNA ploidy pattern was more variable. These findings indicate that chromophobe carcinoma may be the most frequent epithelial component associated with sarcomatoid renal cell carcinoma.

Bilateral chromophobe cell renal carcinoma in tuberous sclerosis complex

We report on a patient with tuberous sclerosis complex and polycystic kidney disease who developed bilateral chromophobe cell renal carcinoma. We discuss the tuberous sclerosis complex, associated bilateral renal cell carcinoma, polycystic kidney disease and chromophobe cell renal carcinoma; a recently established subtype with a rather favorable prognosis. In a patient with tuberous sclerosis complex and multiple space-occupying lesions, a diagnosis of angiomyolipoma should be considered first but bilateral and/or multifocal renal cell carcinoma is a likely diagnosis.

Renal oncocytoma containing "chromophobe" cells

We report a rare case of renal oncocytoma containing occasional "chromophobe" cells. This case suggests an intimate relationship between oncocytoma and "chromophobe" renal cell carcinoma.