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What Are the CD34+ Cells in Benign Peripheral Nerve Sheath Tumors?
Double Immunostaining Study of CD34 and S-100 Protein

Mahmoud A. Khalifa MD, PhD, FRCPC, Elizabeth A. Montgomery MD, Nadia Ismiil MD, Norio Azumi MD, PhD
DOI: http://dx.doi.org/10.1309/C7N9-J2AU-5TB9-5FRL 123-126 First published online: 1 July 2000


To determine whether CD34 expression in nerve sheath lesions was found in a unique cell population or in a subset of nerve sheath cells, we performed double immunohistochemical staining using a standard avidinbiotin complex method with 2 separate color developing systems. We studied 40 neurofibromas and 16 neurilemomas. All lesions strongly expressed S-100 in nuclei and cytoplasm. CD34 was detected in cells having ameboid dendritic cytoplasm present in greatest numbers in Antoni B zones of neurilemomas, myxoid zones of neurofibromas, at the periphery of lobules in both tumor types, and condensed in apposition to perineurium. The CD34+ cells also were detected in normal nerves. They were infrequent in Antoni A zones of neurilemomas. No dual S-100 and CD34 expression was seen. This double immunostaining confirms the presence of a CD34-reactive non-Schwannian cell type in these neural neoplasms. As the CD34+, S-100–-negative cell population is present also in normal nerves and infrequently seen in the areas of cellular neoplastic Schwann cells, CD34+, S-100–negative cells in peripheral nerve sheath tumors most likely are nonneoplastic and may have a supportive function.

Key Words:
  • Double immunostaining
  • CD34
  • S-100
  • Peripheral nerve sheath tumors
  • Neurofibroma
  • Schwannoma
  • Neurilemoma