Immunohistochemistry
S-100 less intense than for neurilemmoma
EMA may be positive due to the presence of perineural elements.
Cytogenetics
Monosomy 22, eliminating one of the NF-2 alleles, has been reported in Schwannomas, neurofibromas and perineuromas1.
Differential diagnosis
See the immunohistochemistry of the differential diagnosis of spindle cell tumours of the pleura.
spindle cell / neurotising naevi: may also be positive for S-100 and CD57. Positivity for HMB45 and tyrosinase distinguishes, but neurotised naevi are negative for Melan-A. Factor XIIIa is positive in neurofibromas but negative in melanocytic naevi.
References
Diagnostic Immunohistochemistry edited by Professor D. J. Dabbs, page 74
1 Hahn HP, Fletcher CDM. The role of cytogenetics and molecular genetics in soft tissue tumour diagnosis - a realistic approach. Current Diagnostic Pathology 2005;11:361-370.
©SMUHT/PW Bishop