Abstract

So called pseudosarcoma of the esophagus is an extremely rare polypoid malignant tumor and a number of cases, totaling 19 cases have been reported in world literatures until 1985. The presenting case is an unique one of pseudosarcoma of the esophagus and we illustrated all microscopic features with mapping, immunoperoxidase stain for cytokeratin and electron microscopic findings to clarify the histogenesis of spindle cells. It is postulated that the spindle cells of pseudosarcoma are transformed from squamous carcinoma cells based on (1) morphological similarity between squamous epithelial cells and spindle cells, (2) positive reaction of immunoperoxidase staining for cytokeratin in the adjacent normal esophageal mucosa, squamous cell carcinoma, spindle cells and giant cells and (3) presence of transformation zone.

• Keywords: Pseudosarcoma;Esophagus