Elston Marianne S, Sehgal Shekhar, Dray Michael, Phillips Elizabeth, Conaglen John V, Clifton-Bligh Roderick J, Gill Anthony J
Department of Endocrinology, Waikato Hospital, Hamilton 3240, New Zealand.
Waikato Clinical Campus, University of Auckland, Hamilton 3240, New Zealand.
J Clin Endocrinol Metab. 2017 May 1;102(5):1447-1450. doi: 10.1210/jc.2017-00165.
Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract arising from the interstitial cells of Cajal. Succinate dehydrogenase (SDH)-deficient GISTs are a unique class of GIST defined by loss of immunohistochemical expression of SDHB, indicating dysfunction of the mitochondrial complex 2; lack of driver mutations in KIT and PDGFRA; and distinctive morphologic features and natural history. To date, all reported SDH-deficient GISTs have arisen in the stomach. We report an SDH-deficient GIST arising in the gastrointestinal tract outside the stomach.
A 29-year-old man with a germline SDHB mutation (p.Arg90*) presented with acute upper gastrointestinal hemorrhage. Endoscopy identified a lesion in the second part of the duodenum, close to the distal common bile duct, consistent with a GIST. Endoscopic ultrasonography and magnetic resonance imaging did not demonstrate metastatic or nodal disease. Open transduodenal excision was performed to remove the tumor. Histologic evaluation confirmed the clinical diagnosis of a GIST, with positive staining for DOG1 and KIT. The mitotic count was low (1 per 50 high-power fields). Immunohistochemistry for SDHB was negative in the presence of an internal control. SDHA expression was retained. No somatic mutations were identified in KIT (exons 9, 11, 13, and 17) or PDGFRA (exons 12, 14, and 18). The germline SDHB mutation and loss of heterozygosity were confirmed on molecular testing of the tumor.
We describe an SDH-deficient GIST occurring outside of the stomach. This case indicates that SDH-deficient GISTs may also arise in the small intestine.
胃肠道间质瘤（GISTs）是起源于 Cajal 间质细胞的胃肠道间叶性肿瘤。琥珀酸脱氢酶（SDH）缺陷型 GISTs 是一类独特的 GIST，其定义为 SDHB 免疫组化表达缺失，提示线粒体复合物 2 功能障碍；KIT 和 PDGFRA 无驱动突变；具有独特的形态学特征和自然病史。迄今为止，所有报道的 SDH 缺陷型 GISTs 均发生于胃。我们报告了一例发生于胃外胃肠道的 SDH 缺陷型 GIST。
一名携带种系 SDHB 突变（p.Arg90*）的 29 岁男性因急性上消化道出血就诊。内镜检查发现十二指肠第二部靠近胆总管远端有一病变，符合 GIST。内镜超声和磁共振成像未显示转移或淋巴结疾病。行开放经十二指肠切除术切除肿瘤。组织学评估证实临床诊断为 GIST，DOG1 和 KIT 染色阳性。有丝分裂计数低（每 50 个高倍视野 1 个）。在有内对照的情况下，SDHB 免疫组化染色为阴性。保留 SDHA 表达。在 KIT（外显子 9、11、13 和 17）或 PDGFRA（外显子 12、14 和 18）中未发现体细胞突变。对肿瘤进行分子检测证实了种系 SDHB 突变和杂合性缺失。
我们描述了一例发生于胃外的 SDH 缺陷型 GIST。该病例表明 SDH 缺陷型 GISTs 也可能发生于小肠。
