Fine-needle aspiration cytology of well-differentiated inflammatory liposarcoma: a case report with histologic follow-up.

Inflammatory liposarcoma is an unusual variant of well-differentiated liposarcoma. We report on the fine-needle aspiration (FNA) cytology findings of a retroperitoneal well-differentiated inflammatory liposarcoma from a 63-yr-old white female. The smears showed numerous dispersed inflammatory cells, with the majority being reactive lymphoid cells and plasma cells. There were scattered, large, atypical cells containing multiple or hyperlobated nuclei with coarse chromatin and abundant ill-defined cytoplasm. The large atypical cells, as well as the inflammatory cells, were also found within the fibrous tissue fragments. The follow-up surgical resection of the tumor demonstrated a well-differentiated inflammatory liposarcoma with coexistent dedifferentiated areas and lipoma-like, well-differentiated liposarcoma. With the appropriate anatomic and radiographic settings, the FNA cytology findings of abundant, reactive inflammatory cells and scattered, large, atypical tumor cells that are CD15-, CD30-, and cytokeratin-negative are highly suggestive of a well-differentiated inflammatory liposarcoma.