[Primary pulmonary sarcoma with spindle-shaped cells. Apropos of a case].

Primary pulmonary sarcoma is a very rare malignant tumour. The authors report a case of a fusiform cell sarcoma simulating a pulmonary metastasis in a woman who previously had a mammary carcinoma. Lymph node invasion is rare. The nature of the tumour was confirmed by histology and aided by immunochemistry or electron microscopy. The primary origin of the tumour can only be confirmed after negative results from careful examination of the marrow, the gastro-intestinal tract, the genito-urinary system and above all the uterus. The prognosis depends on the size of the tumour and the mitotic score. Surgery is the only curative treatment.