[A case of giant renal hamartoma considered as congenital mesoblastic nephroma of adult].

A case of giant renal hamartoma considered as congenital mesoblastic nephroma in an adult is reported. A 24-year-old woman was admitted to our hospital with complaints of macroscopic hematuria and left flank pain. On clinical examination, a large left renal tumor was recognized and radical left nephrectomy was performed. The tumor weighed 2,500 g. On histological examination, the tumor was composed of spindle-shaped cells, that were considered as fibroblasts, surrounded by abundant collagenous interstitial material, and many cystic or tubular structures lined by cuboidal epithelium were also seen in the peripheral region. Because of histological similarity we considered this tumor as congenital mesoblastic nephroma in an adult.