Figure.

Teased and epoxy embedded sections from representative sural nerve biopsies of a patient with IgM-MGUS (a, b) and Waldenström’s macroglobulinemia (WM) (c, d) neuropathy. Both biopsies show combination axonal fiber loss and degeneration (black arrows) with de and remyelination (open arrows). By the electrophysiologic criteria²⁸ the shown IgM-MGUS patient had demyelinating features with axonal loss whereas the WM patient had axonal nerve conductions despite occasional demyelinating teased fibers. Both these patients presented with insidious onset sensory gait ataxia without pain or significant weakness.