关键词: 后肾腺瘤, 病理学特征, 免疫组织化学

Abstract: Objective Metanephric adenoma（MA）is a rare tumor of the urinary system. Its histopatholgy features， differential diagnosis and prognosis were analyzed. Methods Two cases of MA recently diagnosed in our institute were observed and analyzed in the gross，histopathological features and immunohistochemical features. Pathological features were concluded based on clinical information extracted from the medical records and literature review. Results Both tumors were masses with a clear boundary. They also had distinct feature in histology as small cells with high ratio of nucleus to cytoplasm，no nuclear atypia or mitotic figures. The tumor exhibited well- organized tubules，small cell nests，glomeruloid bodies，and sharply demarcated from the adjacent renal parenchyma. The expression of Vimentin ，WT1 and CD57 were positive while CK7，AMACR were negative. Conclusion Metanephric adenoma is a rare kidney primary epithelial origin benign tumor，based on morphological characteristics and immunohistochemical staining results，it can be correctly diagnosed.

Key words: metanephric adenoma, pathological feature, immunohistochemistry