Sarcoma Unit, Department of Histopathology, Royal Marsden Hospital, London UK.
Ann Diagn Pathol. 2013 Oct;17(5):457-63. doi: 10.1016/j.anndiagpath.2012.08.006. Epub 2012 Oct 3.
Dedifferentiation within solitary fibrous tumor is a rare and only recently characterized phenomenon. It differs from malignant solitary fibrous tumor in that there is abrupt transition between classical solitary fibrous tumor and the dedifferentiated component. The latter is a high-grade sarcoma, which can exhibit a number of morphologies, but heterologous differentiation is exceptionally rare. We report a case of dedifferentiated solitary fibrous tumor, with heterologous osteosarcomatous and rhabdomyosarcomatous elements, arising in the deep soft tissue of the thigh of a 59-year-old man. This comprised morphologically and immunohistochemically typical solitary fibrous tumor, juxtaposed to pleomorphic, high-grade malignant neoplasm of 2 distinct lineages. The sharp demarcation between well-differentiated and dedifferentiated components is typical of the dedifferentiation seen in other mesenchymal neoplasms. This expands the range of histopathology of this rare, newly characterized type of malignant progression in solitary fibrous tumor.
去分化在孤立性纤维瘤中是一种罕见的现象，最近才被描述。它与恶性孤立性纤维瘤不同，因为经典孤立性纤维瘤和去分化成分之间有明显的过渡。后者是一种高级别的肉瘤，可以表现出多种形态，但异源性分化非常罕见。我们报告了一例发生在大腿深部软组织的去分化孤立性纤维瘤，伴有异源性骨肉瘤和横纹肌肉瘤成分。该肿瘤由形态学和免疫组织化学表现典型的孤立性纤维瘤组成，与 2 种不同谱系的多形性、高级别恶性肿瘤相邻。分化良好和去分化成分之间的明显界限是其他间叶性肿瘤中所见的去分化的典型特征。这扩大了孤立性纤维瘤中这种罕见的、新描述的恶性进展类型的组织病理学范围。
