Immunohystochemical Study of the Intestinal Stromal Tumors in Dogs-7 Cases and Review of the Literature

Primary spindle cell neoplasms of the gastrointestinal system show considerable morphologic overlaps. Proper histological classification of these neoplasms using only the classical hematoxylin-eosin (HE) stained slides is often difficult and frequently a source of diagnosis error. Thus, the immunohistochemistry is an essential tool in the proper diagnosis and classification of such tumors.In this study we tested and standardised an immunohistochemical protocol used for the differentiation of primary intestinal sarcomas (nonangiogenic, nonlymphogenic intestinal sarcomas) in dogs. The paper also aimed to critically review the state of art in immunohistochemistry of intestinal spindle cell neoplasms currently used in dogs.Seven cases of primary intestinal spindle cell neoplasms were diagnosed and classified using a 6 antibody panel immunohistochemistry. Indirect immunohistochemistry staining for S100 protein, desmin, I±-SMA, CD34, c-Kit and GFAP was conducted using a Leica Bond-Max auto-immunostainer.Based on the immunoreactivity, five stromal tumours were classified as leiomyosarcomas, one fibrosarcoma and one an undifferentiated sarcoma.In most cases of intestinal sarcomas, the proper diagnosis requests the use of immunohistochemistry. The retrospective analysis of these tumours proved that at least in one case, the HE stain was not sufficient for the proper diagnosis and classification of the tumour.