Fig. 5
From: Modern treatment of perineuriomas: a case-series and systematic review
Histology of the biopsy specimen (Hematoxylin and eosin stain) with intrafascicular tumour cells (asterisk) surrounded by collagen fibres (a). Epithelial membrane antigen staining is positive in tumour cells (asterisk) (b). S100 is not expressed in tumour cells but shows entrapped Schwann-cells in pseudo-onion bulbs (asterisk) (c). Immunohistochemical staining for Ki-67 reveals only very few proliferating tumour cells (asterisk) (d)