FCER2 and undifferentiated pleomorphic sarcoma: Likewise, discordant diagnoses are common in the initial evaluation of IPT-like FDCS, which have been misdiagnosed as Hodgkin lymphoma,[14] malignant fibrous histiocytoma,[15] and myofibroblastic tumor.[11,16] Therefore, when an unusual immunoprofile is observed upon the immunohistochemical examination of a malignant spindle cell tumor, additional immunostaining for CD21, CD23, CD35 could be helpful to rule out FDCS, although this tumor is rare.