伴脑膜上皮样旋涡和骨化的去分化脂肪肉瘤

Dedifferentiated liposarcoma with meningothelial like whorls and bone formation

目的 :探讨伴脑膜上皮样漩涡和骨化的去分化脂肪肉瘤的形态特点。方法 :应用常规病理和免疫组化对 1例伴脑膜上皮样漩涡和骨化的去分化脂肪肉瘤进行临床病理分析并复习相关文献。结果 :肿块位于后腹膜 ,直径 17cm ,包膜不完整 ,切面灰白色。肿瘤中大量梭形细胞排列成多个脑膜瘤样漩涡 ,有明显的纤维化、淋巴细胞浸润和出血 ,邻近漩涡处见成熟的骨小梁形成 ;肿瘤内见分化良好的硬化性脂肪肉瘤区域 ,同时伴有黏液性纤维肉瘤区域 ,漩涡与硬化性脂肪肉瘤区域、硬化性脂肪肉瘤与黏液性纤维肉瘤区域二者之间界限清楚 ,呈突然转变之势。结论 :去分化脂肪肉瘤伴脑膜上皮样漩涡和骨形成是十分罕见的 。

Purpose To investigate the morphologic characteristics of dedifferentiated liposarcoma with meningothelial like whorls and bone formation. Methods A case of dedifferentiated liposarcoma with meningothelial like whorls and bone formation was studied by conventional histopathology, immunohistochemistry and literature review. Results The lesion was located in the retroperitoneum and measured 17 cm in dimension. The tumor was ill circumscribed and greyish white in color on cross section. Histologically, spindle to epithelioid cells arranged in concentric whorls resembling meningotheliomas in a hyalinized, fibroconnective tissue background. Metaplastic ossification was located at the periphery of the whorled areas. There was abundant lymphocytic infiltration and focal hemorrhage near the whorled zones. Areas of both well differentiated (sclerosing type) and myxoid fibrosarcoma were present. The transition from the well differentiated liposarcoma areas to the zones exhibiting the whorling pattern or the myxoid fibrosarcoma was abrupt. Conclusions Dedifferentiated liposarcoma with meningothelial like whorls and bone formation is an unusual tumor. The meningothelial like whorls represent a mesenchymal proliferation that may undergo pericytic or myofibroblastic differentiation.