Three cases of pulmonary leiomyosarcoma were presented.The characteristic clinical features were described with review of literature.In comparison with bronchogenic carcinoma

the leiomyosarcoma has some characteristics:1) On chest X-ray

it usually appears as a sharply demarcated

even density round mass

growing rapidly within the lung

it rarely accompanies with hilar or mediastinal lymph node metastasis.2) The preoperative cytological or pathological diagnosis is difficult either by sputum smear or by bronchoscopic biopsy or by fine needle percutaneous aspiration biopsy.31 Pathological differential diagnosis of leiomyosarcoma of lung from anaplastic lung cancer is difficult.In conclusion

the primary pulmonary leiomyosarcoma is a rare malignant tumor

detecting the present illness seriously

paying attention to the chest X-ray films characterize

early surgical resection is the only way to get diagnosis and effective treatment method.