Intraneural biphasic synovial sarcoma: an alternative "glandular" tumor of peripheral nerve

A primary intraneural biphasic synovial sarcoma that arose within the common digital nerve of the hand is reported. The patient, a 16-year-old girl, presented with a small soft tissue mass that clinically and intraoperatively resembled a nerve sheath tumor. The diagnosis of synovial sarcoma was established on the basis of a typical light microscopic appearance and immunohistochemical staining profile. Intraneural biphasic synovial sarcoma resembles "glandular" peripheral nerve sheath tumor, because both are composed of a mixture of spindled mesenchymal cells with admixed glandular epithelial elements. The features allowing differentiation of these two unusual tumors of peripheral nerve are discussed.