MALIGNANT FIBROUS HISTIOCYTOMA OF THE ESOPHAGUS

A 78-year-old man presented with an esophageal polyp that was confirme d by immunohistochemistry and electron microscopy to be malignant fibr ous histiocytoma. The tumor was comprised of a proliferation of spindl e-shaped cells admired with bizarre giant cells, These tumor cells wer e immunoreactive for smooth muscle actin, vimentin, alpha-1-anti-chymo trypsin and CD68. Electron microscopic examination revealed the myofib roblastic and histiocytic features of the tumor cells. No elements of epithelial or myogenic differentiation were found in the tumor. Malign ant fibrous histiocytoma of the esophagus is extremely rare, with 10 c ases being documented so far in the literature. The differential diagn osis of pleomorphic tumors of the esophagus is discussed.