Clinical images: Primary systemic amyloidosis masquerading as necrotizing vasculitis.

Abstract

The patient, a previously healthy woman, developed a small bowel perforation. Surgical examination revealed extensive bowel thickening with diffuse segmental ischemia. Physical examination results were normal except for periorbital ecchymosis, dystrophic nails, and a purpuric rash. Findings on visceral angiography were strongly suggestive of necrotizing vasculitis in all vascular beds, with segmental arterial strictures and fusiform aneurysms as illustrated in the inferior mesenteric artery (A). However, on pathologic examination of the bowel, there was no evidence of vasculitis, whereas significant amyloid deposition was revealed (B) (Congo red stain). Characteristic apple-green birefringence on polarized microscopy confirmed the presence of amyloid (C). Serum immunofixation revealed an M-spike of monoclonal lambda protein. The patient's condition improved remarkably with thalidomide treatment and total parenteral nutrition, with resolution of the M-spike. In a patient with features of vasculitis but negative biopsy results for this disease, the possibility of primary systemic amyloidosis should be considered. Primary amyloidosis can mimic vasculitides, especially giant cell (temporal) arteritis or polymyalgia rheumatica (1-3). Rarely, it can coexist with necrotizing vasculitis of the central nervous system, giant cell arteritis, or vasculitis of the small intestine (1, 4, 5). P. Auethavekiat MD*, N. S. Murali MD*, N. J. Manek MD*, * Mayo Clinic College of Medicine, Rochester, MN.