骨肉瘤是常见的原发性恶性肿瘤，好发于四肢管状骨，发生于颌骨者尚木多，仅占所有骨肉瘤的65％。上下颌骨均可发生，以下颌骨为多。本组4例均发生在下颌骨，现报道如下。例1，男，25岁，因左下颌骨面部肿胀2个月余伴下唇麻木来院就诊。查：左下颌骨膨隆，触及2．5×2.5×2cm肿 Osteosarcoma is a common primary malignancy that occurs in the extremities of tubular bones. It occurs in the jaws of Shangmudo and accounts for only 65% ​​of all osteosarcomas. Both upper and lower jaws can occur, with more jaw below. This group of 4 cases occurred in the mandible, are reported below. Example 1, male, 25 years old, came to the hospital due to swelling of the left mandible for 2 months with numbness of the lower lip. Check: Left mandible bulging, touching 2.5 x 2.5 x 2cm swollen