A typical mesoblastic nephroma: Histopathological entity or specific anatomoclinical form?

Atypical mesoblastic nephroma is a rare kidney tumor mostly which occurred in early infancy. We describe two cases of atypical mesoblastic nephroma diagnosed in infants aged respectively 2 and 3 months. The tumors were completely removed and surgical margins were histologically free of disease. The two patients are well 14 and 9 months after surgery. Microscopically, the tumor was characterized by a densely cellular prolifiration, high mitotic levels, cystic degeneration and necrosis. In the literature, the prognostic is good in patients aged fewer than 3 months and in cases in which the surgical removal was complete.