We report the unusual case of a man with a 5-year history of relapsing Henoch-Schonlein purpura (HSP) and macroscopic polyarteritis nodosa (PAN) as early manifestations of IgAK multiple myeloma. The glomeruli contained monoclonal IgAK deposits, without other immunoglobulins or A light chains. Glomerular deposits lacked the usual electron density but could be demonstrated by immunoelectron microscopy. Multisystem large vessel vasculitis (antineutrophil cytoplasmic antibody negative) produced aneurysms of renal and hepatic arteries, whereas small vessel vasculitis affected the skin and glomeruli, producing a symptom complex of HSP with dermal and glomerular deposits of IgA. We conclude that HSP/overlap syndrome may be the initial manifestation of IgA myeloma and should be considered within the spectrum of monoclonal IgA deposition disease.Henoch-Schonlein purpura (HSP) is a leukocytoclastic vasculitis of cutaneous venules, capillaries and arterioles, often associated with mesangial glomerulonephritis, and sometimes with a necrotizing intestinal vasculitis. IgA deposits are found in areas of cutaneous vasculitis and are usually present in the renal mesangium (1). HSP with nephritis is common in children, but rare in adults. It sometimes follows respiratory tract infections and in such cases is thought to be due to stimulation of the mucosal immune system with formation of circulating immune complexes (ICs) containing polyclonal IgA (2). HSP can also occur in patients with cirrhosis, and in those cases is thought to be due to defective clearance of IgA-containing ICs (3). Rare cases of HSP associated with monoclonal IgA production have been reported (4).Another IgA-mediated disorder, IgA nephropathy, is the most common primary glomerulonephritis in adults and is a common cause of renal failure. The pattern of IgA deposits and glomerular injury in HSP resembles that seen in IgA nephropathy, and many investigators now consider IgA nephropathy to be a renal-limited form of HSP. We report herein an unusual case of HSP with monoclonal IgAKdomerular deposits associated with antineutrophil cytoplasmic antibody (ANCA)-negative polyarteritis nodosa (PAN) as a complication of IgAK multiple myeloma.
CASE REPORTThe patient, a 50-year-old man, developed a purpuric rash on his arms, abdomen, buttocks, and legs, associated with abdominal pain, arthralgias, myalgias, a painful neuropathy, and peripheral edema. Evaluation at another hospital revealed proteinuria and microscopic hematuria. The results of tests for antinuclear antibody (ANA) and cryoglobulins were negative. Biopsy of a purpuric skin lesion showed leukocytoclastic vasculitis, and a diagnosis of HSP was made. He was treated with prednisone 0.5 mg/kg/ day but continued to have arthralgias, myalgias, proteinuria, microscopic hematuria, and flares of purpura. Oral cyclophosphamide was then instituted at a dosage of 1 mg/kg/day, but symptoms and urinary sediment abnormalities continued. A second biopsy of a purpuric skin lesion revealed leukocytoclastic vasculitis with vasc...