Metanephric adenofibroma in a 10-year-old boy: report of a case and review of the literature.

We reported a case of metanephric adenofibroma in a 10-year-old boy to describe the clinical, radiologic, and pathologic features and discuss its treatment and differential diagnosis. Nephrectomy was performed for the patient; final histopathologic evaluation was that of a metanephric adenofibroma. Epithelial and stromal elements were both positive for WT-1, Vimentin, PAX2, and the epithelial tumor cells were also positive for S100, AE1/AE3, PAX8, CK8/18, EMA and a few cells were positive for CK7. Larger vessel wall components were positive for SMA, Des, caldesmon while capillary components were positive for CD10, CD31, and CD34. CA-9, α-inhibin and CD-56 were negative in the neoplasm. The Ki-67 labeling index was <1%. Metanephric adenofibroma is a rare benign renal tumor; the diagnosis of it relies on pathology and immunohistochemistry. As its rarity, there is no standard treatment for this disease. The majority of patients underwent nephrectomy and had good prognosis, as it is a benign neoplasm.