Fine-needle aspiration in liposarcoma: cytohistologic correlative study including well-differentiated, myxoid, and...

We have reviewed cytopathology and the corresponding histopathology material of 86 liposarcomas (55 patients) seen at Institut Curie. The liposarcomas (LS) were well differentiated in 14 cases (9 pure, 2 dedifferentiated, 3 sclerosing), 64 myxoid, and 8 pleomorphic. Twenty-four tumors were primary, 34 recurrent, and 28 secondary. Smears in LS were composed in different proportions of round, spindle cells, lipoblasts, and myxoid and vascular arborizing structures. Pure well-differentiated LS were frequently composed of lipoblasts, and round or spindle cells were occasionally seen. Dedifferentiated and sclerosing liposarcomas were composed of spindle or round cells, but lipoblasts were also occasionally present. Myxoid or vascular arborizing structures were absent. Myxoid LS (including round and spindle cell LS) frequently showed a myxoid background and less frequently vascular arborizing structures. Tumor cells were round or spindle. Lipoblasts were also seen. Pleomorphic LS were composed of an admixture of all cellular and stromal elements. Well-differentiated LS should be distinguished from hibernoma and spindle cell lipoma, and myxoid LS from myxoma, myxoid chondrosarcoma, chordoma, myxoid leiomyosarcoma, and myxoid malignant fibrous histiocytoma. The demonstration of the specific translocation t(12;16)(q13;p11) of myxoid LS is very helpful to establish the diagnosis. Pleomorphic LS should be differentiated from other high-grade sarcomas, whenever possible.