ResultsThe gastrectomy specimen consisted of a 12 x 10 cm segment of stomach with irregular mucosal and serosal surfaces. On sectioning of the antropyloric region, a firm, yellowish-white
We report a case of oesophageal carcinosarcoma with prominent rhabdomyoblastic differentiation. Immunohistochemically, the rhabdomyblasts were mainly reactive to vimentin, cytokeratin, desmin, muscle-specific actin, myosin, and myoglobin, and were surrounded by laminin and type IV collagen-positive basement membranes. The tumour had dual differentiation, 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 mechanism involved in the histogenesis of this lesion. The word carcinosarcoma, from a descriptive point of view, seems the most suitable to describe a tumour composed of both carcinomatous and true sarcomatous elements.
Disruption and loss of basement membranes at interface between carcinomatous and sarcomatous tissues is a frequent finding in sarcomatoid carcinomas. These changes could be consistent with an epithelial origin of the sarcomatous component in these tumors by means of an epithelial-mesenchymal conversion mechanism.
The distribution of the main extracellular matrix components has been investigated immunohistochemically in four cases of breast sarcomatoid carcinomas. The histogenesis of these tumours is still unclear, but most evidence suggests that the sarcomatous component originates from mesenchymal conversion of carcinomatous cells. We found that carcinomatous portions of the tumours were associated with linear basement membrane-like deposition of laminin, type IV collagen and heparan sulphate proteoglycan that partially circumscribed the epithelial nests. The sarcomatous components produced an extracellular matrix immunoreactive to fibronectin, type I, III and VI collagens and tenascin. However, in two cases, in some sarcomatous areas, focal pericellular staining for antibodies to laminin and type IV collagen was seen. These results indicate that modifications observed in the double tissue component of these tumours involve not only the cell shape and the cytoskeleton, but also the components of the extracellular matrix. The significance of these findings and their relevance in the understanding of the phenotypic pattern changes of these biphasic tumours are discussed.
Liposarcoma is a soft tissue tumor usually observed in adults. Although occasional cases have been reported in childhood, it is virtually unknown in infants and small children. Our experience documents a case of liposarcoma in a 6-year-old girl, an extremely rare occurrence in this age-group. The patient underwent wide local excision followed by chemotherapy. Histologically, the tumor was a myxoid type. Differential diagnosis and problems concerning prognosis and therapy of this tumor in children are discussed.
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