Malignant transformation in a hybrid schwannoma/perineurioma: Addition to the spectrum of a malignant peripheral nerve sheath tumor

Malignant transformation in a hybrid schwannoma/perineurioma: Addition to the spectrum of a malignant peripheral nerve sheath tumor

Blog Article

Benign nerve sheath tumors include here schwannomas, neurofibromas and perineuriomas.The malignant counterpart of a nerve sheath tumor is designated as a malignant peripheral nerve sheath tumor (MPNST).Lately, benign nerve sheath tumors comprising more than one component have been described, including hybrid schwannomas/perineuriomas.

However, malignant transformation in a hybrid schwannoma/perineurioma has not been documented so far.Herein, we present a rare case of a young adult male who presented with a soft tissue mass in his right thigh that was excised elsewhere and submitted to us for histopathological review.One of the tissue sections displayed histopathological features of a hybrid schwannoma/perineurioma, including alternate arrangement of benign schwann and perineurial cells, reinforced with S100-P and epithelial membrane antigen positivity, respectively, along with low MIB1 and negative p53 immunostaining.

The other two tissue sections showed a spindly sarcomatous tumor that was immunohistochemically positive for S100-P, CD34, p53 and exhibited high MIB1 (30-40%).Diagnosis of a MPNST arising in here a hybrid schwannoma/perineurioma was made.This unusual case forms yet another addition to the spectrum of a MPNST.