腹内胃肠道外间质瘤临床病理、免疫组织化学及分子遗传学研究

目的探讨腹内胃肠道外间质瘤(extra-gastrointestinal stromal tumors,EGIST)临床病理、免疫组织化学、分子遗传学特点及鉴别诊断。方法用CD117、CD34为主的一组抗体对消化道外腹腔软组织原诊断为平滑肌瘤、平滑肌母细胞瘤及平滑肌肉瘤等病例进行研究,获得9例EGLST,其中5例检测了c-kit基因11号外显子序列。结果患者中男性5例,女性4例,年龄38～72岁,平均61．7岁,其中肠系膜4例,网膜2例,腹膜后2例,1例位于脾门,肿瘤直径5～23cm,平均12．9cm。梭形细胞为主型7例,上皮型1例,混合型1例。此组抗体表达分别为CDll7(8／9)、CD34(5／9)、平滑肌肌动蛋白(d—SMA,3／9)、肌特异性肌动蛋白(MSA,4／9)、结蛋白(0／9)、s-100蛋白(1／9)、蛋白基因产物9．5(PGP9．5,1／9)。2例有c-kit基因11号外显子杂合性突变。交界性2例,分别存活8年和11年,恶性7例,1例无瘤生存4年,1例1年后死于肝转移,1例术后3年及4年两次复发,2例失访,2例随访中。结论消化道外腹腔软组织及腹膜后亦可发生符合GIST形态学、免疫表型及分子生物学特征的原发性间质瘤,生物学行为以交界性及恶性多见,肿瘤性坏死、核分裂象≥5／50HPF及细胞明显异型性对判断恶性有重要参考价值。需与相同部位的平滑肌肉瘤、恶性神经鞘膜瘤等鉴别。

Clinicopathological, immunohistochemical and molecular genetic study of intra-abdomen extra-gastrointestinal stromal tumors

OBJECTIVE: To explore the clinicopathological, immunohistochemical and molecular genetic features of intra-abdomen extra-gastrointestinal stromal tumors (EGISTs) and their differential diagnosis. METHODS: Nine cases of EGISTs from the abdominal cavity or retroperitoneum which were previously diagnosed as leiomyoma, leiomyoblastoma, or leiomyosarcoma etc. by a panel of antibodies such as CD117, CD34, alpha-SMA, MSA, desmin, S-100, and PGP9.5 from which five cases were detected for c-kit gene mutation. RESULTS: The tumors occurred in 5 men and 4 women, the age ranged from 38 to 72 years (mean 61.7 years). Four cases arose from the mesentery, two from omentum, two from retroperitoneum and one located at the hilus of the spleen. The size of tumors ranged from 5 cm to 23 cm (mean 12.9 cm) in diameter and the tumor cell components varied: mainly spindle cells (seven cases), epithelioid cells (one case), mixed cells (one case). Tumors expressed CD117 (8/9), CD34 (5/9), alpha-SMA (3/9), MSA (4/9), desmin (0), S-100 protein (1/9) and PGP9.5 (1/9). Of the five cases examined for heterozygous deletion mutation of 11 exon of the c-kit gene two were found positive. Two borderline cases showed long-term survival of 8 years and 11 years, respectively. In seven malignant cases, two showed adverse outcome, one survived 4 years without recurrence, two were lost in follow up and two new cases were still being in followed. CONCLUSIONS: GIST-type stromal tumors can also occur in the abdomen, most cases were borderline or malignant, tumor coagulative necrosis, mitoses >or= 5 per 50 high-power fields and obvious nuclear atypia indicating malignancy. Differential diagnosis of EGIST including benign or malignant smooth muscle tumors, benign or malignant nerve sheath tumors etc.