Alveolar soft part sarcoma located within deep soft tissues. Image source: Daigeler et al. World Journal of Surgical Oncology 2008, 6:71. The most common location is deep soft tissues of the lower extremities. Other locations include head & neck region, mediastinum, retroperitoneum, uterus, bladder and vagina. Young females are more commonly affected; but it is also seen in infants and children, usually involving the head & neck region.