Miettinen Markku, Makhlouf Hala R, Sobin Leslie H, Lasota Jerzy
Department of Soft Tissue Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
Am J Surg Pathol. 2009 Nov;33(11):1624-32. doi: 10.1097/PAS.0b013e3181ae666a.
A great majority of gastric mesenchymal tumors are gastrointestinal stromal tumor (GIST). A rare group of non-GISTs include myxoid mesenchymal neoplasms. In this report, we describe 12 cases of a distinctive gastric tumor, named here as plexiform fibromyxoma. These tumors occurred in 5 men and 7 women of ages 7 to 75 years (median, 41 y). All tumors were located in the gastric antrum and 6 of them also extended into extragastric soft tissues or into the duodenal bulb. The tumors measured from 3 to 15 cm (median, 5.5 cm). Histologically typical was a plexiform intramural growth with multiple micronodules containing paucicellular to moderately cellular myxoid to collagenous and fibromyxoid neoplastic elements. A prominent, sometimes plexiform capillary pattern was typically present. Extramural components included subserosal nodules, and sometimes more cellular, solid nonplexiform spindle cell proliferation. The tumor cells varied from oval to spindled and had limited atypia and mitotic activity < 5/50 high-power fields. Frequent ulceration, mucosal invasion, and vascular invasion (4 cases) had no adverse significance in these tumors. Immunohistochemically, the tumor cells were positive for alpha smooth muscle actin, and variably for CD10, and were consistently negative for KIT, DOG1, CD34, desmin, and S100 protein. No KIT or platelet-derived growth factor receptor alpha mutations were present in the 3 examined cases. None of the 4 patients who were followed from 9 to 20 years (median, 19 y) developed recurrences or metastases. Additional 3 patients survived 14 to 25 years with unknown tumor status. Review of large numbers of mesenchymal tumors in the esophagus and intestines did not reveal similar tumors. Plexiform fibromyxoma is a distinctive benign gastric antral neoplasm that should be separated from GIST, nerve sheath tumors, and other fibromyxoid neoplasms.
绝大多数胃间质瘤是胃肠道间质瘤（GIST）。一小部分非GIST包括黏液样间质肿瘤。在本报告中，我们描述了12例一种独特的胃肿瘤，在此命名为丛状纤维黏液瘤。这些肿瘤发生在5名男性和7名女性中，年龄为7至75岁（中位年龄41岁）。所有肿瘤均位于胃窦，其中6例还延伸至胃外软组织或十二指肠球部。肿瘤大小为3至15厘米（中位大小5.5厘米）。组织学上典型表现为丛状壁内生长，有多个微结节，含有少细胞至中等细胞的黏液样至胶原性和纤维黏液样肿瘤成分。通常可见突出的、有时为丛状的毛细血管模式。壁外成分包括浆膜下结节，有时还有细胞较多的实性非丛状梭形细胞增生。肿瘤细胞从椭圆形到梭形不等，异型性有限，有丝分裂活性<5/50高倍视野。频繁的溃疡、黏膜侵犯和血管侵犯（4例）在这些肿瘤中并无不良意义。免疫组化显示，肿瘤细胞α平滑肌肌动蛋白阳性，CD10呈可变阳性，而KIT、DOG1、CD34、结蛋白和S100蛋白始终为阴性。在3例检测病例中未发现KIT或血小板衍生生长因子受体α突变。4例随访9至20年（中位随访19年）的患者均未出现复发或转移。另外3例患者存活14至25年，肿瘤状态不明。对大量食管和肠道间质瘤的回顾未发现类似肿瘤。丛状纤维黏液瘤是一种独特的胃窦良性肿瘤，应与GIST、神经鞘瘤和其他纤维黏液样肿瘤相鉴别。
