Multinucleated floret-like giant cells in sporadic and NF1-associated neurofibromas: a clinicopathologic study of 94 cases

Virchows Arch. 2010 Jan;456(1):71-6. doi: 10.1007/s00428-009-0859-y. Epub 2009 Nov 25.

Abstract

Multinucleated floret-like giant cells (MNFGCs), similar to those commonly observed in pleomorphic lipoma and giant cell fibroblastoma, have been occasionally reported in gynecomastia and neurofibromas from patients affected by neurofibromatosis type 1 (NF1). Accordingly, it has been suggested that their detection, especially in an otherwise typical neurofibroma, could be a morphological clue to diagnosis of NF1. The aim of the present study was the identification of MNFGCs in a large series (94 cases) of sporadic and NF1-associated neurofibromas, to assess if their presence may indeed be a morphological marker of NF1. Numerous MNFGCs, namely, those that were easily apparent at low magnification (x50 and x100), were identified only in 5.3% of cases. In 18.1% of cases, a low number of these cells could be observed but only after a careful search, especially at higher magnification (x200 and x400). Immunohistochemically, all MNFGCs were stained with vimentin and CD34, but not with S-100 protein. Interestingly, there was no statistically significant correlation between MNFGCs (presence or absence) and NF1 (p = 0.73), gender (p = 0.59), age (p = 0.43), and site of tumor (cutaneous vs deep-seated soft tissue; p = 0.27). Our clinicopathologic findings suggest that MNFGCs in an otherwise typical neurofibroma are not a reliable marker of NF1, likely representing a morphological reactive change of the indigenous dermal or endoneurial fibroblasts or dendritic cells in response to unknown microenvironmental stimuli.

Publication types

  • Multicenter Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antigens, CD34 / analysis
  • Child
  • Female
  • Giant Cells / pathology*
  • Humans
  • Male
  • Middle Aged
  • Neurofibroma / pathology*
  • Neurofibromatosis 1 / pathology
  • Retrospective Studies
  • S100 Proteins / analysis
  • Skin Neoplasms / pathology*

Substances

  • Antigens, CD34
  • S100 Proteins