CARCINOSARCOMA OF THE ESOPHAGUS WITH RHABDOMYOBLASTIC DIFFERENTIATION

We report a case of oesophageal carcinosarcoma with prominent rhabdomy oblastic differentiation. Immunohistochemically, the rhabdomyblasts we re mainly reactive to vimentin, cytokeratin, desmin, muscle-specific a ctin, myosin, and myoglobin, and were surrounded by laminin and type I V collagen-positive basement membranes. The tumour had dual differenti ation, carcinomatous and sarcomatous, but also showed evident features of transition between the two components, suggesting a common origin. An epithelial-mesenchymal conversion could be the pathogenetic mechan ism involved in the histogenesis of this lesion. The word carcinosarco ma, from a descriptive point of view, seems the most suitable to descr ibe a tumour composed of both carcinomatous and true sarcomatous eleme nts.