Spindle Cell/Sclerosing Rhabdomyosarcoma : Congenital
The congenital/infantile form of sclerosing/spindle cell rhabdomyosarcoma is characterized by gene fusions involving VGLL2 and NCOA2 or CITED2 genes. Less common are TEAD1-NCOA2 and SRF-NCOA2 fusions. The tumor is present at birth or develops within 1 year of age, usually on the trunk. It consists of fascicles of low-grade appearing spindle cells that resemble low-grade leiomyosarcoma. Scattered rhabdomyoblasts may be present. It carries an excellent prognosis.