NCIt definition : A congenital mesoblastic nephroma characterized by increased cellularity, sheet-like
proliferation of fibroblastic cells, and increased mitotic activity. Necrotic changes
are commonly present.;
Alternative definition : NICHD: A congenital mesoblastic nephroma that is characterized by increased cellularity,
sheet-like proliferation of fibroblastic cells, and increased mitotic activity. There
is a suggested linkage with infantile fibrosarcoma that is based on both containing
the same t(12;15)(p13;q25) translocation, resulting in the ETV6/NTRK3 fusion. This
type is associated with risk of recurrence.;