[Small intestinal tumors with skeinoid fibers. Report of 3 cases with immunohistochemical and ultrastructural study].

Three cases of small intestinal stromal tumors with skeinoid fibers are presented and are confronted to the 15 cases found in the literature. These tumors are characterized by the presence of intercellular eosinophilic globules that stain positively on periodic acid-Schiff stain. Ultrastructurally, these structures are composed of tangles of curved banded (45 nm) fibers simulating an appearance of skeins. By immunohistochemistry, tumor cells express vimentin only. These tumors seem to be derived from the enteric plexus.