Superficial leiomyomas of the gastrointestinal tract with interstitial cells of Cajal.

OBJECTIVE: Some authors suggest common origin of gastrointestinal stromal tumors from stem cells, which may show diverse differentiation. There are reports in which cells morphologically identical to the interstitial cells of Cajal 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. MATERIALS AND METHODS: We analyzed 8 cases of superficial leiomyomas and one deep leiomyoma, received in our institutions as endoscopically or surgically obtained material. The tumor sections were immunohistochemicaly stained with CD117, CD34, NF, S100, αSMA, desmin, caldesmon and mast cell antigen. RESULTS: All leiomyomas showed diffuse positivity for αSMA, caldesmon and desmin. All of them had CD117 and CD34 positive cells morphologically identical to the interstitial cells of Cajal between smooth muscle fibers, 5 had S-100 and NF positive cells and 2 showed positivity for GFAP. The cells were found in different quantity; they were usually diffusely scattered through the tumors without predilection site, forming small groups in some areas. CONCLUSION: CD177, CD34, S-100 and NF positive cells are present in superficial leiomyomas and they may suggest common origin of GI stromal tumors.