Background: Carcinosarcoma is one of the less common tumors of the lung and is composed of a mixture of malignant epithelial and mesenchymal elements of the type ordinarily seen in malignancies of adults. The carcinomatous component is mostly epidermoid and sometimes adenomatoid or undifferentiated. The mesenchymal part is mostly a spindle cell sarcoma and sometimes a polymorphocellular sarcoma. Differentiation as osteosarcoma and chondrosarcoma is rare.
Case report: This report describes the case of a patient with carcinosarcoma of the lung composed of epidermoid carcinoma and chondrosarcoma. A left hilar mass was incidentally diagnosed. The patient was submitted to surgical exploration and a left lower lobectomy with dissection of local lymph nodes was performed. At microscopy the tumor was composed of both epithelial and stromal malignant component. The epithelial component consisted of poorly-differentiated squamous cell carcinoma and the stromal component consisted of chondrosarcoma. He remains well 30 months later.
Conclusion: The prognosis of patients with carcinosarcoma is not always unfavourable. Potentially curative surgical resections should always be attempted. Pathologists should be aware of a wrong diagnosis of undifferentiated small cell lung carcinoma which eliminates the patient from surgery.