Pleomorphic malignant peripheral nerve sheath tumor

KER, keratin, detected by a mixture of CAMS.2, MAK-6, and AEl /AE3 EMA, epithelial membrane antigen VIM, vimentin DES, desmin MSA, muscle-specific actin SMA, smooth muscle (alpha isoform) actin CALD, h-caldesmon S-1 OOP, S-100 protein LM, laminin UL, Ulex europaeus I lectin binding OCN, osteocalcin PRMS, pleomorphic rhabdomyosarcoma PLPS/DLPS, pleomorphic and dedifferentiated liposarcoma PLMS/DLMS, pleomorphic and dedifferentiated leiomyosarcoma MPNST, pleomorphic malignant peripheral nerve sheath tumor MFH, malignant fibrous histiocytoma DCHOR, dedifferentiated chordoma DCHS, dedifferentiated chondrosarcoma POCS, pleomorphic osteosarcoma. 

Pleomorphic Malignant Peripheral Nerve Sheath Tumor... 

Malignant peripheral nerve sheath tumor (MPNST) may likewise assume a pleomorphic appearance. In most instances, that tumor variant shows patterns of reactivity for S-100 protein, CD56, CD57, and collagen type IV that are superimposable with those of better differentiated (spindle cell) MPNSTs." In the absence of focal S-100 protein expression and foci with conventional appearances, it is very difficult (if not impossible) to render this diagnosis with certainty. Unlike spindle cell variants of MPNST, pleomorphic subtypes have not been shown to be desmin-reactive. 

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