Congenital mesoblastic nephroma (CMN), light micrograph. CMN is a mesenchymal neoplasm of the kidney that usually presents by the age of 6 months. It is the most common congenital renal neoplasm. Three histologic variants have been described - classic (25%), cellular (65%), and mixed (10%). It has excellent prognosis with 95% survival rate following complete resection. The image shows cellular variant of CMN. It consists of plump spindle or ovoid cells arranged in densely packed sheets or poorly-formed fascicles. A few dilated vessels with staghorn configuration are seen near the top. The cellular variant resembles infantile fibrosarcoma and carries ETV6-NTRK fusion.