NCIt definition : A congenital mesoblastic nephroma characterized by the presence of interlacing fascicles
of fibroblastic cells, low mitotic activity, and collagen formation.;
Alternative definition : NICHD: A congenital, mesoblastic nephroma that is characterized by the presence of
interlacing fascicles of fibroblastic cells, low mitotic activity, and collagen formation.
It is often diagnosed by prenatal ultrasound or within 3 months of birth, and closely
resembles infantile fibromatosis.;