Metanephric adenoma of the left kidney in a 59-year-old female

female with a nonspecific abdominal pain and palpable mass in the central abdomen on the left side. A well circumscribed, large tumour of the left kidney compressing abdominal structures such as aorta, main inferior vain and descending large bowel was visualised by radiological studies. There was no haematuria, and both kidneys were found to be secreting urine. Total left transperitoneal nephrectomy was performed. Microscopic examination revealed tightly packed, uniform, small epithelial tumour cells forming small acini and tubules. There was no infiltrative growth pattern. Vascular invasion, pleomorphism or anaplasia and mitotic activity were absent. After a microscopic and immunohistochemical examination, metanephric adenoma (MA) was diagnosed. Metanephric adenoma is a rare benign renal tumour. Only 0.2% of adult renal epithelial neoplasms are diagnosed as MAs. The case description is accompanied by a literature review in which we characterise this entity (its aetiology, symptoms, macroand microscopic features). Differential diagnosis and therapeutic approach are also discussed.