目的：探讨29例上皮样胃肠间质瘤(gastrointestinal stromal tumors，GIST)的组织学形态和免疫组织化学特点以及诊断和鉴别诊断，对临床正确诊断治疗和判断预后具有十分重要的临床意义。方法：回顾性分析安阳市肿瘤医院病理科2009年月3月至2016年8月321例完整切除GIST标本，经筛查并重新阅片诊断上皮样GIST 29例。结果：29例上皮样GIST，发生胃部15例，小肠2例，肠系膜3例，直肠4例，腹腔3例，腹膜后1例，盆腔1例。恶性GIST 25例，良性4例。瘤细胞丰富，胞质嗜酸或透明，部分瘤细胞核质比高，核大小不等具有多形性，核分裂较多，可伴有多灶凝固性坏死，间质多数伴有黏液样变性。组织结构形成器官样、片状、巢状及腺泡状等。免疫组织化学CD34，DOG-1在上皮样GIST均弥漫阳性(阳性率100%)，CD117阳性率(86%)。结论：上皮样GIST发生部位广泛，形态多变，易误诊其他上皮样分化的肿瘤；免疫组织化学CD34，DOG-1，CD117在上皮样GIST诊断及鉴别诊断中具有重要价值；如肿物较大、细胞丰富、核分裂多、间质黏液样变性；绝大多数要考虑恶性GIST。
Clinicopathologic features of 29 cases of epithelioid gastrointestinal stromal tumors
Objective: To investigate the histological and immunohistochemical features of 29 cases of epithelioid gastrointestinal stromal tumors (GIST), as well as the diagnosis and differential diagnosis, which is of great clinical significance for the clinical correct diagnosis, treatment and prognosis. Methods: A total of 321 cases of GIST were retrospectively analyzed from March, 2009 to August, 2016. Twenty-nine cases of epithelioid GIST were screened and re-examined. Results: Among 29 cases of epithelioid GIST, there were 15 cases of stomach, 2 cases of small intestine, 3 cases of mesentery, 4 cases of rectum, 3 cases of abdominal cavity, 1 case of retroperitoneum and 1 case of pelvic cavity. There were 25 cases of malignant GIST and 4 cases of benign. Tumor cells were rich, cytoplasmic was eosinophilic or transparent, the nuclear ratio of some tumor cells was high, nuclear size ranged and was polymorphic, more mitotic, accompanied by focal coagulation necrosis, interstitial cells were most associated with myxoid degeneration. The structures of tissue were organ-like, flake, nest and alveolar shape, etc. Immunohistochemical staining of CD34 and DOG-1 was positive in epithelioid GIST (positive rate 100%) and CD117 (positive rate 86%). Conclusion: Epithelioid GIST is widely distributed in many parts of the body, and it is easy to misdiagnose other epithelial-like tumors. Immunohistochemical staining of CD34, DOG-1 and CD117 is of great value in the diagnosis and differential diagnosis of epithelioid GIST, such as tumor mass, cell-rich, nuclear division, and mucinous stromal degeneration; the vast majority should consider the malignant GIST, so as to provide an important guiding significance for clinical correct diagnosis and treatment.