Walsh & Hoyt: Pathology

The pathologic hallmark of AIDP is a variable perivenular mononuclear cell infiltrate with segmental demyelination and relative preservation of axons in the peripheral nervous system (PNS). The pathologic findings are remarkably consistent regardless of whether or not there is an antecedent illness or precipitating event. Perivenular infiltrates composed of lymphocytes and macrophages are seen primarily surrounding endoneural and epineural venules of the PNS. Investigators since 1919 have described virtually all parts of the PNS as a site of involvement.