2005 Volume 44 Issue 4 Pages 255-258
Background: Fine needle aspiration cytology plays an important role in making a definitive diagnosis of soft-tissue tumors. We report a case of extraskeletal myxoid chondrosarcoma encountered by us recently, with emphasis on the cytological findings.
Case: A 47-year-old man. Imaging revealed a multilobular cystic mass, 10×15cm in size, arising in the skeletal muscles in the posterior aspect of the left thigh. The lesion appeared as a low-signal-intensity area on T1-weighted MR images and high-signal-intensity area on T2-weighted MR images. A massive sarcoma with myxoid stroma was suspected. Fine needle aspiration cytology revealed round or oval cells in a background of myxoid stroma containing microfibril-like structures. Diverse patterns of cellular arrangement were observed, such as small clusters of pair cells in a funicular configuration. The nuclear-cytoplasmic ratio was high. Fine granular chromatin was observed in the nuclei, and wrinkles and constrictions were observed at the nuclear edge. Histologically, the extracted tumor exhibited lobulation with an abundance of a myxoid stroma. The tumor cells exhibited syncytial growth, and were arranged in cords or in small clusters. Immunohistochemically, the tumor cells were positive for S-100 protein and vimentin.
Conclusion: Thus, the characteristic cytological findings were that of the tumor cells arranged in diverse patterns, in an abundant myxoid background containing microfibril-like structures, and wrinkles and constrictions were found at the edge of the cellular nuclei. However, it was not so easy to make a differential diagnosis from other myxoid tumors only from the cytological features.
