背景:PEComa是一种间充质肿瘤,可发生在包括子宫和软组织在内的各种器官中。PEComas由血管周围上皮样细胞组成,血管平滑肌脂肪瘤(AML),透明细胞糖肿瘤(CCST),和淋巴管肌瘤病(LAM)被认为是与PEComa家族肿瘤相同谱系的病变。组织学上,常见的PEComa显示上皮样细胞的固体或片状增殖。这伴随着扩张血管数量的增加。这里,我们报告一例胰腺PEComa伴明显炎性细胞浸润。
方法:一名74岁男性患者因急性阑尾炎行阑尾切除术。术后计算机断层扫描和磁共振成像显示胰腺尾部有30×25mm非对比增强的圆形病变。影像学表现与恶性肿瘤一致,并进行了远端胰腺切除术。组织学上,病变的大部分区域浸润有炎症细胞。几个上皮样细胞有很大的,圆形原子核,不同的核仁,观察到嗜酸性粒细胞胞浆。观察到梭形肿瘤细胞。在肿瘤细胞周围观察到精致和扩张的血管。免疫组织化学,异型细胞αSMA阳性,MelanA,HMB-45和TFE3。肿瘤细胞的细胞学特征和免疫组织化学染色结果导致胰腺PEComa的诊断。
结论:已经定义了肝AML的一种组织学变异,称为炎性亚型。少量肿瘤细胞存在明显的炎性细胞浸润,占病变的一半以上,和炎性肌纤维母细胞瘤样外观。据我们所知,这是胰腺PEComa伴严重炎症的首次报道。PEComa也是来自血管周围上皮样细胞的肿瘤的通用术语,比如AML,CCST,还有LAM.因此,该病例被认为是PEComa的炎性亚型.它具有不典型的PEComa的独特形态。这种组织学表型应得到广泛认可。
BACKGROUND: PEComa is a mesenchymal tumor that can occur in various organs including the uterus and soft tissues. PEComas are composed of perivascular epithelioid cells, and angiomyolipoma (AML), clear cell sugar tumor (CCST), and lymphangiomyomatosis (LAM) are considered lesions of the same lineage as tumors of the PEComa family. Histologically, a common PEComa shows solid or sheet-like proliferation of epithelioid cells. This is accompanied by an increase in the number of dilated blood vessels. Here, we report a case of pancreatic PEComa with marked inflammatory cell infiltration.
METHODS: A 74-year-old male patient underwent an appendectomy for acute appendicitis. Postoperative computed tomography and magnetic resonance imaging revealed a 30 × 25 mm non-contrast-enhanced circular lesion in the tail of the pancreas. The imaging findings were consistent with a malignant tumor, and distal pancreatectomy was performed. Histologically, most area of the lesion was infiltrated with inflammatory cells. A few epithelioid cells with large, round nuclei, distinct nucleoli, and eosinophilic granular cytoplasm were observed. Spindle-shaped tumor cells were observed. Delicate and dilated blood vessels were observed around the tumor cells. Immunohistochemically, the atypical cells were positive for αSMA, Melan A, HMB-45, and TFE3. The cytological characteristics of the tumor cells and the results of immunohistochemical staining led to a diagnosis of pancreatic PEComa.
CONCLUSIONS: A histological variant known as the inflammatory subtype has been defined for hepatic AML. A small number of tumor cells present with marked inflammatory cell infiltration, accounting for more than half of the lesions, and an inflammatory myofibroblastic tumor-like appearance. To our knowledge, this is the first report of pancreatic PEComa with severe inflammation. PEComa is also a generic term for tumors derived from perivascular epithelioid cells, such as AML, CCST, and LAM. Thus, this case is considered an inflammatory subtype of PEComa. It has a distinctive morphology that is not typical of PEComa. This histological phenotype should be widely recognized.