Tickoo S K, Lee M W, Eble J N, Amin M, Christopherson T, Zarbo R J, Amin M B
Department of Pathology, Henry Ford Hospital, Detroit, Michigan, USA.
Am J Surg Pathol. 2000 Sep;24(9):1247-56. doi: 10.1097/00000478-200009000-00008.
On light microscopic examination, the morphologically overlapping features of granular eosinophilic cytoplasm in renal oncocytoma and the eosinophilic variants of chromophobe renal cell carcinoma and conventional (clear cell) renal cell carcinoma may pose difficulties in diagnosis. We investigated the ultrastructure of 5 renal oncocytomas, 7 eosinophilic variants of chromophobe renal cell carcinoma, and 5 eosinophilic variants of conventional (clear cell) renal cell carcinoma. Special attention was paid to mitochondria and microvesicles and interrelations thereof. The electron microscopic features were correlated with the light microscopic findings. All of the tumors had abundant mitochondria. Although abundant microvesicles were present in all of the chromophobe renal cell carcinomas, scant numbers of microvesicles were also sometimes present in renal oncocytomas (2 of 5) and in the eosinophilic variant of conventional (clear cell) renal cell carcinoma (1 of 5). The mitochondria in all three types of renal neoplasms studied differed in morphology, being predominantly uniform and round with predominantly lamellar cristae in renal oncocytoma, variable in shape and size with predominantly tubulocystic cristae in chromophobe renal cell carcinoma, and swollen and pleomorphic with rarefied matrix and attenuated cristae in the eosinophilic variant of conventional (clear cell) renal cell carcinoma. Variable numbers of mitochondria in all of the chromophobe renal cell carcinomas had outpouchings of the outer membranes, some of which carried parts of inner membrane within them. These outpouchings closely resembled the nearby cytoplasmic microvesicles, as did the tubulocystic cristae of the mitochondria. Some microvesicles contained homogeneous, electron-dense, finely granular matrix, similar to that seen in mitochondria. In one of seven chromophobe renal cell carcinomas, microvesicles were present in rough endoplasmic reticulum, and in two others, mitochondria were present within some vesicles. These features strongly suggest a close relationship between the microvesicles and mitochondria. Based on the role of vesicle formation in normal mitochondriogenesis, and some of our observations, we propose that defective mitochondriogenesis may be the source of microvesicles in chromophobe renal cell carcinomas.
在光学显微镜检查中，肾嗜酸细胞瘤、嫌色肾细胞癌的嗜酸性变体以及传统（透明细胞）肾细胞癌中嗜酸性变体的颗粒状嗜酸性细胞质在形态学上有重叠特征，这可能给诊断带来困难。我们研究了5例肾嗜酸细胞瘤、7例嫌色肾细胞癌的嗜酸性变体以及5例传统（透明细胞）肾细胞癌的嗜酸性变体的超微结构。特别关注了线粒体和微泡及其相互关系。电子显微镜特征与光学显微镜检查结果相关。所有肿瘤都有丰富的线粒体。虽然所有嫌色肾细胞癌中都有大量微泡，但肾嗜酸细胞瘤（5例中的2例）和传统（透明细胞）肾细胞癌的嗜酸性变体（5例中的1例）中有时也有少量微泡。所研究的三种类型肾肿瘤中的线粒体形态不同，肾嗜酸细胞瘤中的线粒体主要呈均匀圆形，嵴主要为板层状；嫌色肾细胞癌中的线粒体形状和大小各异，嵴主要为管状囊状；传统（透明细胞）肾细胞癌的嗜酸性变体中的线粒体肿胀且多形，基质稀薄，嵴变细。所有嫌色肾细胞癌中数量不等的线粒体有外膜的囊状突出，其中一些囊状突出内含有部分内膜。这些囊状突出与附近的细胞质微泡非常相似，线粒体的管状囊状嵴也是如此。一些微泡含有均匀的、电子致密的细颗粒状基质，类似于线粒体中的基质。在7例嫌色肾细胞癌中的1例中，微泡存在于粗面内质网中，在另外2例中，一些囊泡内有线粒体。这些特征强烈提示微泡与线粒体之间存在密切关系。基于囊泡形成在正常线粒体生成中的作用以及我们的一些观察结果，我们提出线粒体生成缺陷可能是嫌色肾细胞癌中微泡的来源。
