Sarcoma botyroides is a type of

Rhabdomyosarcoma*Tumours with skeletal muscle differentiation. *Most common soft tissue sarcoma of childhood and adolescence*Three histological types - Embryonal, alveolar and pleomorphic.*"Rhabdomyoblasts" is the characteristic finding in all the three types*Embryonal RMS- Most common type. It has three variants namely sarcoma botryoides, spindle cell and anaplastic variant. Sarcoma botyroides develops in the wall of hollow mucosa lined structures like nasopharynx, common bile duct, bladder and vagina. "Cambium layer" is seen where tumour abuts the mucosa of an organ.*Alveolar RMS - associated with PAX3-FOXO1a fusion gene and PAX7-FOXO1a fusion gene *Of all the types, sarcoma botryoides has the best prognosis while others are often fatal.(Ref: Robbins 8/e p1253)