[Clinicopathological studies on pseudosarcomatous lesion of the upper gastrointestinal tract].

Thirty-seven cases of pseudosarcomatous lesion (PSL) are studied clinicopathologically on the upper gastrointestinal tract. Majority of the cases showed polypoid tumor lesions, and only minority of them showed non-polypoid lesions. All showed surface erosion or ulcer. Atypical proliferating cells, easily mistaken for sarcoma, were observed in the stroma. The cellular atypia of the stromal cells was related on site and shape; polypoid or non-polypoid. The lesions with severe atypia were observed mainly in the esophago-cardiac junction, lower portion of esophagus and cardia. Non-polypoid lesions showed mild atypia. Immunohistochemically, atypical stromal cells were positive only for vimentin, so considered to be fibroblastic cells. In order to avoid over-diagnosis on biopsy of the upper gastrointestinal tract, recognition of the clinicopathological features of PSL is very important.