Introduction: Polyarteritis nodosa (PAN) is a necrotizing vasculitis of small to-medium-sized vessels, rarely associated with hematologic neoplasms.
Case report: We report a 44-year-old man with a history of monoclonal gammopathy of undetermined significance (MGUS) who presented with rapidly progressing sensorimotor peripheral neuropathy. Two weeks after onset the patient developed severe acute acral and retinal ischemia. MR-angiography and nerve biopsy revealed a systemic necrotizing vasculitis (PAN type). At this time, bone marrow biopsy identified a smoldering multiple myeloma. Immediate immunosuppressive and anti-neoplastic treatment (steroids, immunoglobulins, bortezomib combined with cyclophosphamide followed by lenalidomide maintenance) resulted in a favorable clinical outcome. After 4 years, the patient is in good clinical condition with sustained partial remission from myeloma and without evidence of relapse of PAN.
Conclusion: This is a remarkable case of a histologically confirmed peripheral neuropathy due to polyarteritis nodosa associated with progression of MGUS to multiple myeloma. Immediate diagnosis and combined immunosuppressive and anti-neoplastic treatment may improve the outcome of this potentially life-threatening clinical condition.