Superficial leiomyoma of the gastrointestinal tract with interstitial Cajal-like cells

Abstract

Objective: Some authors suggest common origin of all gastrointestinal stromal tumours from stem cells, which may show diverse differentiation. There are reports in which cells with a morphology of interstitial Cajal-like cells are found in deep leiomyomas. The aim of this study was to demonstrate CD117 positive cells in superficial gastrointestinal (GI) leiomyomas and to find other cells that would suggest diverse differentiation in histologically typical leiomyoma. Method: We have analyzed 9 cases of superficial leiomyomas, received in our institutions as endoscopically or surgically obtained material. The tumour sections were immunohistochemically stained with CD117, CD34, NSE, S 100, α-S MA and desmin. Results: There were one esophageal and 8 colonic superficial leiomyomas, 2 of which rectal. Histological analysis showed presence of stellate cells morphologically similar to the interstitial cells of Cajal. Immunohistochemical analysis showed that in addition to diffuse positivity for -SMA and desmin, all leiomyomas showed presence of CD117, CD34 and NSE positive cells between smooth muscle cells, while six of them showed presence of S-100 positive cells. The cells were found in different quantity, usually were scarce and diffusely scattered through the tumours without predilection site. Conclusion: The presence of CD177, CD 34, S-100 and NSE positive cells in superficial leiomyomas may suggest a common origin of GI stromal tumours.