Endoneurial and perineurial cells and nerve sheath fibroblasts were S-100 negative [1, 9], whereas there was EMA-antigen immunoreactivity of the perineurial sheath, in particular the residual perineurial sheath, underscoring the localized intraneural form of neurofibroma [8]. The gene discussed is MUC1; the disease is plexiform neurofibroma.