Figure 1. Neuropathic Histologic Changes in Neurofascin-155–Immunoglobulin G4–Positive Patients.

Teased fiber preparations from 4 patients taken from the sural (A, B) and sciatic (C, D) nerves. Shown are variable degrees of paranodal separation and myelin swelling (thickening) from least (A) to most involved (C) in the fascicular proximal sciatic biopsy. Also seen in the fascicular sciatic biopsy is frank segmental demyelination (D) where segments are void of osmium staining (light regions). Electron micrographs show myelin separation within the paranodal region (E) and the internodal areas (F). Also observed were Schwann cell cytoplasm around sites of prior unmyelinated fibers now filled with collagen-forming collagen pockets (G) indicative of small fiber involvement.