Pleomorphic sarcoma, NOS

Pleomorphic sarcoma NOS is a diagnosis of exclusion in case in which ancillary methods fail to demonstrate a specific line of differentiation. They are synonymous with storiform/pleomorphic MFH. They account for 5% of all sarcomas in adults, most commonly occurring as deep seated lesions in the extremities in the elderly. There is immunohistochemical positivity only for vimentin and sometimes of a few cells for SMA.