摘要目的：探讨琥珀酸脱氢酶缺陷型胃肠道间质瘤（ GIST）的临床病理特征。方法应用免疫组织化学EnVision法检测琥珀酸脱氢酶亚单位B（ SDHB）在192例GIST患者肿瘤组织中的表达情况，对其中SDHB缺陷型GIST的临床病理特征进行分析，并进行CKIT基因第9、11、13、17号外显子和血小板源性生长因子受体α（ PDGFRA）基因第12和18号外显子的基因检测及随访。结果192例GIST中7例SDHB蛋白缺陷（阴性），占3.6％（7／192）。这7例患者中男性4例，女性3例；年龄35～84岁（中位年龄56岁，平均年龄60岁）；其中6例发生于胃，1例发生于肠系膜。组织学特征：混合细胞型4例，上皮样细胞型3例；发生于胃壁的肿瘤在肌层内呈多结节状或丛状生长，瘤细胞丰富，胞质弱嗜碱性，胞质中可见空泡。5例发生淋巴结转移，其中1例还发生肝脏及胰腺转移，其余2例无转移。7例SDHB蛋白缺陷型GIST均未发现CKIT和PDGFRA基因突变。3例获访，随访时间24～127个月，其中2例无肿瘤复发，1例于术后24个月死亡（原因不明）。结论 SDHB蛋白缺陷型GIST具有独特的临床病理特征，均为野生型病例且预后较好。

abstractsObjective To investigate clinicopathologic features of succinate dehydrogenase-deficient gastrointestinal stromal tumors ( SDH-deficient GIST).Methods Immunohistochemical EnVision technique was used to assess the expression of succinate dehydrogenase subunit B ( SDHB) in 192 cases of GIST.Cases of SDH-deficient GIST were further evaluated for the presence of CKIT exons 9, 11, 13 and 17 mutations and PDGFRA exons 12 and 18 mutations with clinical followed-up data.Results Seven of the 192 cases showed SDHB-deficiency(3.6%,7/192).The patients ranged in age from 35 to 84 years(median =56 years;mean=60 years).Four were male and three were female.Six tumors involved stomach and one involved mesentery.Histopathologic features of SDHB-deficient GIST included four cases of mixed-cell type and three of epithelioid cell type.The tumors commonly involved muscularis propria of the stomach as multiple nodules, creating a plexiform pattern.The tumors had high cellularity with cytoplasmic vacuolization.Five cases developed lymph node metastases including one also metastasizing to liver and pancreas.Two cases showed no evidence of metastasis.None of the 7 cases of the SDHB-deficient GIST had CKIT exons 9, 11, 13 and 17 mutations and PDGFRA exons 12 and 18 mutations.Three of the seven SDHB-deficient GIST cases had followed-up data:two did not recur and one died after 24 months of surgery of unknown cause.Conclusion SDHB-deficient GIST has characteristic clinicopathologic features with wide-type CKIT gene and a favorable prognosis.