Miettinen M, Sarlomo-Rikala M, Lasota J
Department of Soft Tissue Pathology, Armed Forces Institute of Pathology, Washington, DC, USA.
Ann Chir Gynaecol. 1998;87(4):278-81.
Gastrointestinal stromal tumour (GIST) is the designation used here to identify the most common subset of gastrointestinal mesenchymal tumours specific to those sites. These tumours have unique histological, immunophenotypic and molecular genetic features that set them apart from typical smooth muscle tumours and schwannomas; however, by tradition, they have been classified as GI-smooth muscle tumours, or stromal tumours/smooth muscle tumours. GISTs occur predominantly in persons over 40 years of age with an equal sex incidence. Benign GISTs outnumber the malignant ones by a margin of 10:1. GISTs occur throughout the gastrointestinal tract, but are most common in the stomach (60-70%) and small intestine (30%). GISTs are rare in esophagus, colon and rectum. Histologically they may show a spindle cell or epithelioid pattern (the former largely corresponds with the designation of cellular leiomyoma and the latter with that of leiomyoblastoma). Immunohistochemically most GISTs are positive for CD34 and c-kit protein (CD117); the latter is quite specific for GISTs among mesenchymal tumours. Genetically GISTs commonly show DNA losses in the long arm of chromosome 14, and c-kit gene mutations occur at least in some cases. c-kit is also expressed in the interstitial cells of Cajal, the gastrointestinal pacemaker cells, and relationship of GISTs to these cells has been proposed recently. GISTs differ histologically, immunohistochemically and genetically from typical (esophageal) leiomyomas that are negative for c-kit and CD34 and neither show DNA-losses in 14q nor c-kit mutations. Evaluation of malignancy of GISTs is based on mitotic count, tumour size and extra-gastrointestinal spread. Tumours with mitotic counts higher than 5/10 high power fields or larger than 10 cm have a significant risk for recurrence and metastasis and are considered histologically malignant; however, some tumours with mitotic activity < 1/10HPF may metastasize indicating some uncertainty in malignant potential of GISTs, especially those larger than 5 cm.
胃肠道间质瘤（GIST）是本文用于识别特定于胃肠道部位的最常见的胃肠道间充质瘤子集的名称。这些肿瘤具有独特的组织学、免疫表型和分子遗传学特征，使其有别于典型的平滑肌瘤和神经鞘瘤；然而，按照传统，它们被归类为胃肠道平滑肌瘤或间质瘤/平滑肌瘤。GIST主要发生于40岁以上人群，男女发病率相等。良性GIST的数量比恶性GIST多10倍。GIST可发生于整个胃肠道，但最常见于胃（60 - 70%）和小肠（30%）。GIST在食管、结肠和直肠中罕见。组织学上，它们可能表现为梭形细胞或上皮样模式（前者大体上与细胞性平滑肌瘤相对应，后者与成平滑肌瘤相对应）。免疫组化方面，大多数GIST对CD34和c-kit蛋白（CD117）呈阳性；后者在间充质瘤中对GIST具有相当的特异性。遗传学上，GIST通常显示14号染色体长臂的DNA缺失，并且至少在某些情况下会发生c-kit基因突变。c-kit也在胃肠道起搏细胞即 Cajal间质细胞中表达，最近有人提出了GIST与这些细胞的关系。GIST在组织学、免疫组化和遗传学上与典型的（食管）平滑肌瘤不同，后者c-kit和CDs4呈阴性，且在14q既不显示DNA缺失也不发生c-kit突变。GIST恶性程度的评估基于有丝分裂计数、肿瘤大小和胃肠道外扩散情况。有丝分裂计数高于5/10高倍视野或肿瘤大于10 cm的肿瘤复发和转移风险显著，组织学上被认为是恶性的；然而，一些有丝分裂活性＜1/10HPF的肿瘤可能会转移，这表明GIST的恶性潜能存在一定不确定性，尤其是那些大于5 cm的肿瘤。
