①低倍镜下,瘤细胞巢呈“器官样”或“腺泡状”排列,巢之间为宽窄不一的纤维性间隔,腺泡间为衬覆单层扁平内皮细胞的裂隙状或血窦样毛细血管网,网状纤维染色可清晰显示腺泡状结构;腺泡结构的形成是由于位于细胞巢中央的细胞失去黏附性发生脱离所致。 ②高倍镜下,瘤细胞大小和形状较为一致,呈大圆形或多边形,胞质丰富,内含嗜伊红色颗粒,细胞边界清晰。70%病例于胞质内可见PAS阳性的针状或棒状结晶物,耐淀粉酶消化。瘤细胞的核大,染色质细致或空泡状,核仁明显,核分裂象和坏死不多见。少数病例瘤细胞可有明显异型性及核分裂象。 ③发生于婴幼儿和儿童的病例,瘤细胞多呈小多边形,腺泡状结构较少或较小,低倍镜下瘤细胞常呈实性片状排列。 ④部分病例瘤细胞胞质透亮或空泡状,易被误诊为转移性肾透明细胞癌。 ⑤肿瘤周边常见扩张静脉,血管内常见瘤栓,是肿瘤早期发生转移的主要原因。 Figure Alveolar Soft Part Sarcoma. The tumor shows a uniform nested (上) or pseudoalveolar architecture (下). Figure Alveolar Soft Part Sarcoma. Alveolar structures contain epithelioid cells with abundant eosinophilic cytoplasm, vesicular nuclei, and prominent central nucleoli. Figure Solid Variant of Alveolar Soft Part Sarcoma. The tongue is a relatively common anatomic site. Fig. Alveolar soft part sarcoma arising in child showing clustering and small nests of tumor cells. Fig. Alveolar soft part sarcoma. Periodic acid–Schiff (PAS) staining with diastase reveals varying amounts of intracellular crystalline material. |