Epithelioid/granular soft tissue lesions: correlation of cytopathology and histopathology

Polygonal shaped epithelioid cells are not an infrequent component of soft tissue mass lesions. Such cells exist in association with other cellular shapes (eg, spindle, pleomorphic, stellate, etc) in both tumors and tumor-like conditions. Conversely, only a handful of soft tissue lesions contain either a pure or predominant epithelioid cell population. The cytoplasmic texture of such cells may be finely or coarsely granular, striated, vacuolated, or have combinations of these features. Since a relatively small body of literature on fine needle aspiration cytopathology of soft tissue exists (as compared to other body sites), and there is a lack of using the fine needle aspiration technique for soft tissue tumors in most medical centers, most pathologists are precluded from having the opportunity to correlate the cytopathology and histopathology of epithelioid soft tissue lesions. The aim of this review is to highlight the morphologic features (as seen in both tissue sections and aspiration smears) of this group of soft tissue lesions in order to assist the reader in their recognition, discuss the cytomorphologic and histomorphologic similarities and differences among these lesions, and delineate the limitations in their recognition particularly with the cytologic method.