An approach to pleomorphic sarcomas: can we subclassify, and does it matter?

The term malignant fibrous histiocytoma (MFH) has been supplanted by undifferentiated pleomorphic sarcoma (UPS). Even now, however, a number of pleomorphic neoplasms are classified as UPSs when in fact at least a subgroup of these can be more precisely classified as a pleomorphic sarcoma with a specific line of differentiation. Still others are pseudosarcomas, most commonly sarcomatoid carcinomas. This review will discuss historical aspects of MFH/UPS as well as provide an approach to the pleomorphic malignant neoplasm with a discussion of useful ancillary techniques in the evaluation of such cases.