Laboratory of Surgical and Molecular Pathology, Hospital Sírio Libanês, rua Dona Adma Jafet 91, São Paulo, SP 01308-050, Brazil.
World J Gastroenterol. 2010 Jan 28;16(4):522-5. doi: 10.3748/wjg.v16.i4.522.
Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasia and currently well recognized as a distinct entity with characteristic morphological, immunohistochemical and molecular findings. We report a case of PEComa arising in the antrum of a 71-year-old female with melena. The tumor, located predominantly in the submucosa as a well delimited nodule, measured 3.0 cm in diameter and was completely resected, with no evidence of the disease elsewhere. Histologically, it was composed predominantly of eosinophilic epithelioid cells arranged in small nests commonly related to variably sized vessels, with abundant extracellular material, moderate nuclear variation and discrete mitotic activity. No necrosis, angiolymphatic invasion or perineural infiltration was seen. Tumor cells were uniformly positive for vimentin, smooth muscle actin, desmin and melan A. Although unusual, PEComa should be considered in the differential diagnosis of gastric neoplasia with characteristic epithelioid and oncocytic features and prominent vasculature.
血管周上皮样细胞瘤（PEComa）是一种罕见的间叶性肿瘤，目前被认为是一种具有特征性形态、免疫组织化学和分子特征的独特实体。我们报告了一例发生在 71 岁女性胃窦部的 PEComa 病例，该患者有黑便。肿瘤主要位于黏膜下层，呈界限清楚的小结节，直径 3.0cm，完全切除，无其他部位疾病的证据。组织学上，它主要由嗜酸性上皮样细胞组成，排列成小巢，通常与大小不等的血管有关，伴有丰富的细胞外物质、中等程度的核异型性和离散的有丝分裂活性。未见坏死、血管淋巴管浸润或神经周围浸润。肿瘤细胞均弥漫表达波形蛋白、平滑肌肌动蛋白、结蛋白和黑色素 A。尽管不常见，但在具有特征性上皮样和透明细胞样特征以及明显血管的胃肿瘤的鉴别诊断中应考虑到 PEComa。
