Primary pulmonary leiomyosarcomas are a rare malignant tumor with generally poor prognosis. They pose important problems of differential diagnosis especially with pulmonary metastatic sarcoma. They are subdivided into two categories those originating from pulmonary parenchyma and those originating from pulmonary arteries. The authors describe a case of 54-year-old woman that had her left upper lobe mass checked. The diagnosis was made based on the microscopic examination of the percutaneous trans-thoracic needle biopsy. The general examination did not show any metastatic lesions in other areas. The treatment was based on chemotherapy followed by a surgical resection. The patient did not experience recurrences or complications.