Vasculogenic mimicry in gastrointestinal stromal tumor of the stomach: A case report

Abstract

Here we report a case of gastrointestinal stromal tumor of the stomach showing vasculogenic mimicry phenotype. A well demarcatednodule, measuring 5 cm in diameter, was found incidentally in the stomach of a 66-year-old Japanese man. The tumor consisted of a dense proliferation of fairly uniform spindle cells with a prominent nuclear palisading pattern. Immunohistochemically, tumor cells showed strong positivity for KIT (CD117) and CD34. In an extensive area of the tumor, we found periodic acid-Schiff-positive patterned pseudo-vascular channels filled with a large amount of red blood cells. The interior surface of these structures was directly lined by tumor cells but not CD31-positive vascular endothelial cells. In addition, tumor cells showed a vascular phenotype, expressing vascular endothelial growth factor and vascular endothelial-cadherin. We also observed elevated expression of retinoic acid-metabolizing enzyme CYP26A1, which has been shown to have an oncogenic function in carcinogenesis. Since vasculogenic mimicry results from the ability of tumor cell plasticity, our observations suggest an unidentified insight into neoplasia of a gastrointestinal stromal tumor.