Incisional and Excisional Biopsy

The incisional biopsy revealed a piece of oral mucosa covered with stratified squamous epithelium and supported by connective tissue which was almost completely occupied by a lesion of neural origin.  The latter was made up of lobules of myxoid neural tissue, in some areas, with central nerve bundles.  These lobules are surrounded by a connective tissue capsule (Figure 3).  The neural bundles were made up of spindle-shaped cells with wavy nuclei suspended on a delicate background of collagen fibers.  Immunohistochemistry markers with S-100 protein were positive for nerve fibers (Figure 4).

Figure 3.  Low power (x100) histology shows multiple lobules of well-demarcated nerve tissue separated by denser connective tissue.

Figure 4. Low power (x100) immunohistochemistry using antibody to S-100 protein.  The nerve lobules are positive with central areas of more concentrated staining consistent with a central nerve bundle.