Occlusive microangiopathy by immunoglobulin (IgM-kappa) precipitation: pathogenetic relevance in paraneoplastic cryoglobulinemic neuropathy.

Histological, immunohistochemical and ultrastructural sural nerve and skin biopsy findings in a case of cryoglobulinemia secondary to an IgM-kappa-producing non-Hodgkin lymphoma are described. The main finding was an occlusive microangiopathy present in both the sural nerve and the skin. Widespread cryoglobulin deposits of the proliferated vasa nervorum were associated with pronounced changes probably evoked by ischemia. Moderate perivascular inflammation, but no florid vasculitis was additionally present. Our observations indicate that occlusive microangiopathy by precipitated cryoglobulins may be a relevant pathogenetic factor in cryoglobulinemic peripheral neuropathy.