Monarch Disease Ontology id MONDO_0017043 (congenital mesoblastic nephroma) is a low grade childhood congenital malignant neoplasm arising from the kidney. It is characterized by the presence of fibroblastic cells. The majority of cases occur in the first year of life. Complete excision is usually associated with an excellent prognosis. Also known as: CMN, CMn, stromal nephroma, malignant.