Sensorimotor perineuritis--an autoimmune disease?

The literature contains a single description of sensory perineuritis (Asbury et al 1972). These patients demonstrated a painful, distal, sensory neuropathy, and examination of peripheral nerve biopsies revealed focal thickening and inflammatory infiltrates of the perineurium. We report a patient with sensorimotor peripheral nerve dysfunction, accompanied by progressive slowing of nerve conduction velocity. Examination of a sural nerve biopsy demonstrated focal thickening of the perineurium, inflammatory infiltrates, and necrosis of perineurial cells. Immunohistology revealed a patchy precipitation of IgG and IgM on perineurial cells. Ultrastructurally, mononuclear cells were found adjacent to perineurial cells undergoing necrosis. The patient showed gradual improvement partially coinciding with a course of steroid therapy. We suggest that this neuropathy is caused by damage to the perineurial barrier possibly by an immune-mediated destruction of perineurial cells and subsequent compression of the endoneurial content by perineurial scarring.