2020 Volume 73 Issue 11 Pages 665-668
Six neoplastic discontinuous masses were found in a breeding sow slaughtered in Yamagata Prefecture, Japan. They occurred in the serosal surface of the ileum. Two were approximately 7×6×5 cm and the others were 2×1×1 cm in size. The surface was milky white, solid and elastic, and the cross-section showed the same color, organizing abscess and necrosis. Microscopically, the masses composed of spindle-shaped tumor cells, which had oval-to-spindle nuclei and abundant eosinophilic cytoplasm were arranged in streams and bundles. Mitosis was extremely rare. Immunohistochemically, the tumor cells were strongly positive for vimentin, KIT and DOG‐1, weak for α‐SMA, and negative for CK and S‐100. Based on histological and immunohistochemical findings, the masses were diagnosed as a gastrointestinal stromal tumor. To the best of our knowledge, this is the first report on GIST arising from ileum in a pig.
