Peripheral neuropathies and lymphoma without monoclonal gammopathy: a new classification.

Recent progress in immunopathological studies of peripheral nerve and lymph node fragments together with 16 personal cases and numerous clinicopathological reports have suggested a new classification of peripheral neuropathies (PN) and lymphomas. These are: (1) PN due to local infiltrations by a T-cell lymphoma: (2) acute polyradiculoneuritis due to active demyelination and associated with infiltrates of a T-cell lymphoma in the epineurium, resembling Marek's disease (which is a T-cell lymphoma); (3) B-cell lymphoma proliferation which may be restricted to or predominate in the peripheral nervous system, with a large clinicopathological heterogeneity ranging from localized forms to ascending polyradiculoneuropathies; (4) angiotropic lymphoma, which is a B-cell lymphoma and may present as an acute mononeuropathy; (5) patients with acquired immunodeficiency syndrome due to lymphomatous infiltrates in the endoneurium, of which 2 cases of PN have been reported; (6) PN associated with organomegaly, endocrinopathy, M-component and skin lesions, certain cases being associated with a plasmocytoma and sometimes Castleman's disease but without any monoclonal gammopathy: (7) classic Guillain-Barré syndrome, prone to develop in patients with extraneural lymphoma but without any lymphomatous infiltrates in the peripheral nervous system; (8) certain cases (4 out of 16 in our series) where there is no clear relationship between PN and lymphoma, and there are mainly features of axonal degeneration. Inflammatory perivascular infiltrates were sometimes present in the epineurium.