<prompt> Answer this question truthfullyWhat are the historical and symptomatic characteristics of metanephric adenoma?  <response>: <reason> Metanephric adenoma are often asymptomatic. Possible symptoms of metanephric adenoma include: Hematuria Abdominal distension Abdominal painPolycythaemia is a characteristic finding seen in approximately 10 of patients with metanephric adenoma. 