[A case of so-called carcinosarcoma of the lung].

A 65-year-old male was admitted to our institute because of bloody sputum. A tumor in right S6 was detected by X-ray, CT and MRI. Bronchoscopic study showed that the right lower bronchus was occluded by the tumor, in which non-epithelial malignant cells were detected. Therefore right bilobectomy was performed. This tumor was a pedunculated endobronchial type measuring 6 x 4 x 3cm. Histologically, the tumor presented carcinomatous (squamous cell carcinoma and adenocarcinoma) and sarcomatous elements. Immunohistologically, many malignant cells were positively stained by vimentin and muscle-actin, which suggested differentiation from muscle components.