Sarcomatoid carcinomas (SC) of the lung are a heterogeneous group of non-small cell lung carcinomas (NSCLC) containing a sarcoma or sarcoma-like component. SC may represent an epithelial neoplasm undergoing divergent tissue differentiation originating from a single clone. These tumors are the most common pulmonary neoplasms that exhibit a composition by spindled or pleomorphic tumor cells. As such, many of them may be confused easily with true sarcomas diagnostically unless special immunohistological or ultrastructural analyses are performed. Accurate diagnostic workup is crucial for the management of these uncommon tumors .
Reactivity is expected for keratin, epithelial membrane antigen, or collagen type IV in the sarcoma-like elements in SC, although it may be focal. Electron microscopy often shows the presence of junctional complexes between tumor cells, with or without pericellular basal lamina and cytoplasmic skeins of intermediate filaments. Current terminological preferences are such that several formerly used terms--including "spindle-cell carcinoma," "pulmonary blastoma," "squamous cell carcinoma with pseudosarcomatous stroma," "pseudosarcoma," and "carcinosarcoma"--are now encompassed by the more generic designation of "sarcomatoid carcinoma." The clinical course of patients with this neoplasm is aggressive, with an overall 5-year survival rate approximating 20% .
With regard to the origin of neoplastic spindle and giant cells, three hypotheses can be considered. First, carcinoma cells change into neoplastic spindle and giant cells and these cells still are carcinoma. This idea is supported by many investigators because the transition of carcinoma cells into spindle cells occasionally is recognized. Second, although these cells originate from carcinoma, they obtain mesenchymal differentiation and change into true sarcoma. Third, these cells originate from sarcoma and differentiate into carcinoma .
Although sarcomatoid carcinomas are generally believed to be more aggressive and have a poorer prognosis than ordinary lung carcinomas, no statistical analysis has been reported. Except for the report from the Armed Forces Institute of Pathology by Fishback et al. 2 They reported that tumor size > 5 cm, a clinical Stage > Stage I, and lymph node involvement shortened patient survival, significantly. The median survival of patients with sarcomatoid carcinoma was 10 months, which, when compared with that of ordinary lung carcinomas in the literature (20 months for adenocarcinoma, 18.5 months for squamous cell carcinoma, and 12.6 months for large cell carcinoma), was brief. However, in the current study as in our case series there was no significant difference between the prognosis of patients with sarcomatoid carcinoma and that of patients with nonsarcomatoid, non-small cell carcinoma of the lung .
As in every non-small cell lung cancer, early detection, accurate diagnosis and an aggressive operative management is the mainstay of the best chances of long-term survival in these unusual tumors of the lung. The role of adjuvant or neo-adjuvant chemoradiotherapy has not been proved beneficial alone, but they play an important role as an adjunct to standard accepted operative treatment.