CUTANEOUS INTRANEURAL GLOMUS TUMOR

The unusual occurrence of a glomus tumor within a small, deep dermal n erve is reported. This phenomenon has been described previously only o nce in the literature. The lesion appeared as a painful cutaneous nodu le in the shoulder of a 67-year-old woman. Microscopically, a typical solid, smooth muscle actin-positive glomus tumor was seen, encircled c ompletely by neural tissue in the deep dermis. There was no extension of the tumor beyond the nerve. Immunohistochemically, the nerve fibers surrounding and within the tumor were positive for S-100 protein and neurofilament. The presence of perineurium surrounding the glomus tumo r was confirmed by a layer of epithelial membrane antigen-positive cel ls. In view of the absence of normal glomus bodies in the nerves, an o rigin from a less specialized perivascular cell is proposed.