Miettinen M, Sobin L H, Sarlomo-Rikala M
Department of Soft Tissue Pathology, Armed Forces Institute of Pathology, Washington, District of Columbia 20306-6000, USA.
Mod Pathol. 2000 Oct;13(10):1134-42. doi: 10.1038/modpathol.3880210.
Gastrointestinal (GI) stromal tumor (GIST) is the designation for the major subset of GI mesenchymal tumors and encompasses most tumors previously classified as GI smooth muscle tumors. Although GISTs typically express CD117 (KIT), often express CD34, and sometimes express alpha-smooth muscle actin (SMA), the relative frequency of these markers has not been characterized in large series of GISTs of different sites, and the CD117 expression has not been fully characterized in intra-abdominal tumors. In this study, we immunohistochemically analyzed 292 GISTs throughout the GI tract, including omentum and mesentery, and compared the immunoreactivities with 211 other tumors that may enter in the differential diagnosis. GISTs were defined in this study as CD117-positive primary spindied or epithelioid mesenchymal tumors of the GI tract, omentum, or mesentery. The CD34 positivity of GISTs varied from 47% in small bowel to 96 to 100% in rectum and esophagus, whereas SMA expression showed the opposite patterns and was most frequent in the GISTs of small bowel (47%) and rarest in the GISTs of rectum and esophagus (10-13%). Desmin was seen only occasionally. S100 positivity was rare but was seen most frequently in small intestinal GISTs (15%). True leiomyomas from esophagus, muscularis mucosae of colorectum, and pericolic leiomyomas similar to uterine leiomyomas were negative for CD117 and CD34 and positive for SMA and desmin (46 of 46). Inflammatory fibroid polyps of stomach and small intestine were negative for CD117 but were often positive for CD34 (6 of 8) and variable for SMA (3 of 8). Inflammatory myofibroblastic tumors involving gastric or colonic wall were negative for CD117 but some showed CD117-positive endothelia. GI schwannomas were all negative for CD117 and positive for S100 protein (11 of 11). Extremely focal CD117 positivity was seen in the neoplastic cells of some retroperitoneal leiomyosarcomas and liposarcomas. Among other CD117-positive tumors were intestinal metastatic melanomas (8 of 11) and extraskeletal Ewing's sarcomas (5 of 11), two of which were abdominal. In conclusion, strong CD117 expression defines most primary GI mesenchymal tumors as GISTs, which show different patterns for CD34 and SMA in various parts of the GI tract. Some unrelated CD117-positive tumors (melanomas, Ewing's sarcomas) should not be confused with GISTs.
胃肠道（GI）间质瘤（GIST）是GI间叶性肿瘤的主要类型，包括大多数以前归类为GI平滑肌肿瘤的肿瘤。尽管GIST通常表达CD117（KIT），常表达CD34，有时表达α-平滑肌肌动蛋白（SMA），但这些标志物在不同部位的大量GIST中的相对频率尚未得到明确，并且CD117在腹腔内肿瘤中的表达也尚未完全明确。在本研究中，我们对整个胃肠道（包括大网膜和肠系膜）的292例GIST进行了免疫组织化学分析，并将其免疫反应性与211例可能参与鉴别诊断的其他肿瘤进行了比较。本研究中GIST被定义为胃肠道、大网膜或肠系膜的CD117阳性原发性梭形或上皮样间叶性肿瘤。GIST的CD34阳性率从小肠的47%到直肠和食管的96%至100%不等，而SMA表达呈现相反的模式，在小肠GIST中最常见（47%），在直肠和食管GIST中最罕见（10% - 13%）。结蛋白仅偶尔可见。S100阳性罕见，但在小肠GIST中最常见（15%）。来自食管的真性平滑肌瘤、结直肠黏膜肌层的平滑肌瘤以及类似于子宫平滑肌瘤的结肠周围平滑肌瘤CD117和CD34阴性，SMA和结蛋白阳性（46例中的46例）。胃和小肠的炎性纤维性息肉CD117阴性，但CD34常为阳性（8例中的6例），SMA变化不定（8例中的3例）。累及胃或结肠壁的炎性肌纤维母细胞瘤CD117阴性，但一些显示CD117阳性的内皮细胞。GI神经鞘瘤CD117均为阴性，S100蛋白阳性（11例中的11例）。在一些腹膜后平滑肌肉瘤和脂肪肉瘤的肿瘤细胞中可见极局灶性的CD117阳性。其他CDl17阳性肿瘤包括肠道转移性黑色素瘤（11例中的8例）和骨外尤因肉瘤（11例中的5例），其中2例为腹部肿瘤。总之，强烈的CD117表达将大多数原发性GI间叶性肿瘤定义为GIST，其在胃肠道的不同部位显示出不同的CD34和SMA模式。一些不相关的CD117阳性肿瘤（黑色素瘤、尤因肉瘤）不应与GIST混淆。
