We describe a rare case of malignant teratoma involving the entire right lung. A 28 years old man was admitted to the hospital with severe respiratory failure and general malaise. Chest X-ray showed a dense opacity of the entire right lung, accompanied by pleural effusion. At autopsy, the right lung was completed replaced by a mass of variegated appearance combining cystic spaces and solid areas. Microscopically, the lung tumor exhibited a polymorphous histological picture. Most of the tissue had a malignant mesenchymal appearance, which included areas of chondrosarcoma, chondroblastic osteosarcoma, well differentiated liposarcoma, and undifferentiated pleomorphic sarcoma. Other areas of the tumor showed malignant epithelial components consistent with bronchial and urothelial mucosa with also scattered islands of pigmented epithelium of probable neuronal or retinal nature.