肾脏上皮样色素性透明细胞肿瘤病理形态观察

Melanotic epithelioid clear cell tumor of kidney： report of three cases

目的 探讨上皮样色素性透明细胞肾脏肿瘤形态学特点,加强对该肿瘤的认识,减少误诊.方法 回顾性分析2000余例肾脏肿瘤,符合上皮样色素性透明细胞肿瘤3例,通过HE、免疫组织化学EnVision法观察3例肿瘤形态学特点,对其中1例行超微结构观察,同时复习相关文献.结果 女性2例,男性1例,2例形态学表现为透明细胞癌样,1例见透明细胞和嗜酸性细胞构成乳头结构.免疫组织化学上皮标记及S-100蛋白均为阴性,HMB45均为阳性,2例Melan A阳性.电镜末见黑色素小体结构.结论 色素性透明细胞上皮样肿瘤是非常罕见的肾脏肿瘤,病理学特征兼有肾细胞癌、上皮样血管平滑肌脂肪瘤与黑色素瘤等肿瘤特征,免疫组织化学有利于鉴别诊断.其可能是上皮样血管平滑肌脂肪瘤的一种亚型.

Objective To study the pathologic features and immunophenotype of 3 cases of melanotic epithelioid clear cell tumor of kidney. Methods More than 2000 cases of renal tumors were retrospectively reviewed. Three cases of melanotic epithelioid clear cell tumor were identified.Immunohistochemical study was carried out using the paraffin-embedded tissue samples. Electron microscopy Histologically, 2 cases showed a clear cell carcinoma-like pattern. Papillary structures covered by clear cells and eosinophilic cells were observed in 1 case. Immunohistochemical study showed that the tumor cells in all cases expressed HMB 45. Two of them were also positive for Melan A. The staining for epithelial markers and S-100 protein was negative. Melanosomes were not identified by ultrastructural examination.Conclusions Melanotic epithelioid clear cell tumor is a rarely seen neoplasm of kidney. There are some histologic overlaps with renal cell carcinoma, epithelioid angiomyolipoma and melanoma.Immunohistochemical study is useful in confirming the diagnosis. The tumor represents a morphologic variant of epithelioid angiomyolipoma.