Alveolar soft-part sarcoma has been originally described as a unique pathological entitiy by Christopherson, Foote, and Stewart in 1952, who have chosen its name because of their uncertainty in determining from which cells the tumor arose. The tumor is generally considered to be malignant and originates in soft tissue, the most commonly in the deep tissues of the extremities. The case, reporting here, illustrated several of the recognized characteristics of alveolar soft-part. sarcoma, both clinically and pathologically and is described in view of its rarity of its kind and difficulty of accurate diagnosis. The patient was a 29 year old male who has complained of a adult. fist-sized mass on posterolateral aspect of left arm for one year. Roentgenographic findings showed multiple metastatic lesions on both lung fields, left humerus, skull and cervical spine. The mass on the same site recurred after excision and hemoptysis probably due to aggravation of the metastatic lesions of the both lungs developed 4 months later. He died 8 months after surgery.