In recent literature, there have been case reports of an extremely rare entity characterized by hybrid peripheral nerve tumors consisting of elements of neurofibroma, schwannoma, and/or perineurioma. The authors present a unique case of a patient with multiple painful hybrid tumors with negative genetic testing for neurofibromatosis Type 1 and no clinical evidence of neurofibromatosis Type 2 or schwannomatosis.
A 28-year-old woman presented with tentatively diagnosed schwannomatosis. She had painful bilateral retromastoid scalp tumors as well as multiple other painful tumors in the distribution of the saphenous, femoral, and sciatic nerves. Her family history was significant for a paternal grandfather with a solitary schwannoma. The patient underwent multiple surgical procedures for tumor resection, including tumors in the regions of the retromastoid scalp, bilateral sciatic nerves, left femoral nerve, and left axilla. These tumors were examined and evaluated histologically. Within the tumors, components of both neurofibromas and schwannomas were found, even though these 2 peripheral nerve sheath tumors have been long considered to be distinct entities. This case report suggests a distinct syndrome that has not previously been appreciated.
Abbreviations used in this paper:EMA = epithelial membrane antigen; NF1 = neurofibromatosis Type 1; NF2 = neurofibromatosis Type 2; PNST = peripheral nerve sheath tumor.
Address correspondence to: Shih-Shan Lang, M.D., Department of Neurosurgery, Hospital of the University of Pennsylvania, 3 Silverstein, 3400 Spruce Street, Philadelphia, Pennsylvania 19104. email: email@example.com.
Please include this information when citing this paper: published online September 14, 2012; DOI: 10.3171/2012.8.JNS111841.
GonzalvoAFowlerACookRJLittleNSWheelerHMc-DonaldKL: Schwannomatosis, sporadic schwannomatosis, and familial schwannomatosis: a surgical series with longterm follow-up. Clinical article. J Neurosurg114:756–7622011
KazakovDVPithaJSimaRVanecekTShelekhovaKMukensnablP: Hybrid peripheral nerve sheath tumors: schwannoma-perineurioma and neurofibroma-perineurioma. A report of three cases in extradigital locations. Ann Diagn Pathol9:16–232005
MichalMKazakovDVBelousovaIBiscegliaMZamecnikMMukensnablP: A benign neoplasm with histopathological features of both schwannoma and retiform perineurioma (benign schwannoma-perineurioma): a report of six cases of a distinctive soft tissue tumor with a predilection for the fingers. Virchows Arch445:347–3532004
PatilSPerryAMaccollinMDongSBetenskyRAYehTH: Immunohistochemical analysis supports a role for INI1/SMARCB1 in hereditary forms of schwannomas, but not in solitary, sporadic schwannomas. Brain Pathol18:517–5192008
RodriguezFJStratakisCAEvansDG: Genetic predisposition to peripheral nerve neoplasia: diagnostic criteria and pathogenesis of neurofibromatoses, Carney complex, and related syndromes. Acta Neuropathol123:349–3672012