FNA of extraskeletal myxoid chondrosarcoma: cytomorphologic, EM, and X-ray microanalysis features

Extraskeletal myxoid chondrosarcoma, an unusual soft tissue lesion which preferentially affects the extremities, is a prime candidate for "pathologist performed" fine-needle aspirates (FNA) because it preferentially affects the extremities [Enzinger and Shiraki, Hum Pathol 1972;3:421-435] and is usually an accessible lesion. Cytomorphologically, the neoplasm consists of clusters of fairly uniform cells, lacking cartilaginous differentiation, with a metachromatic matrix when stained with Diff-Quik (DQ). While subtle, this neoplasm has distinct features and must be distinguished for other neoplasms in the differential diagnosis because patient evaluation, prognosis, and therapy will vary greatly. We present a case characteristic of this tumor in which FNA derived material was subjected to light microscopy, X-ray microanalysis, and immunohistochemical studies; each modality provided data essential to the correct diagnosis.