Esophageal squamous cell carcinoma characterized by extensive chondroid differentiation

A rare case of carcinoma characterized by extensive chondroid elements at a site of primary esophageal and metastatic lesion is reported. The patient was a 67-year-old man complaining of dysphagia due to an ulcerative lesion at the lower middle esophagus. He underwent irradiation treatment prior to surgery. Histologically, the tumor consisted of both carcinomatous and chon droid elements and had invaded deeply into the esophageal wall. The carcino matous cells had gradually become chondroid cells embedded within an extens ive extracellular matrix. In addition, the metastatic lesion showed finding s similar to those of the primary lesion. Immunohistochemistry revealed tha t both carcinomatous and chondroid elements were immunostained with cytoker atin and epithelial membrane antigen, suggesting an epithelial nature to th e chondroid cells. Conversely, only chondroid cells were positively stained for S-100 protein. Furthermore, bone morphogenetic proteins (BMP) were pos itive for chondroid cells and their surrounding carcinomatous cells. Given the apparent transition between carcinomatous and chondroid cells based on microscopy and immunohistochemical findings in the present case, we conclud ed that the chondroid cells were derived from carcinomatous cells. In addit ion, our findings suggest that BMP produced by carcinomatous cells lead to chondroid differentiation of the carcinoma cells.