Necrotizing Angiitis of the Small Intestine Related to AA-Amyloidosis: A Novel Association

Abstract

A 71-year-old man with intestinal pseudo-obstruction was found to have a diffusely thickened adynamic small bowel with AA-amyloid in submucosal vessels and muscularis propria, foreign body giant cell reaction to amyloid, and necrotizing angiitis. The mucosa was unremarkable. Immunostains demonstrated numerous CD68+ monocyte/macrophages and CD8+ T cells associated with the amyloid deposits. The patient had no evidence of systemic vasculitis and no underlying cause for AA-amyloidosis was identified. Necrotizing angiitis coexistent with amyloid angiopathy has been reported in brain and temporal arteries, but not in the gastrointestinal tract and not with AA-amyloid. The inflammatory cell infiltrates in this case are consistent with a foreign-body and/or cell-mediated immunologic reaction to AA-amyloid, although a role for these cells in amyloid formation cannot be excluded.

Primary Localized Amyloidosis of the Intestine: A Pathologist Viewpoint

“…Immunohistochemical stains were also performed in some cases to substantiate the diagnosis. Other histological features included mucosal ulceration, amyloid angiopathy, necrotizing angiitis [31], foreign body giant cell reaction [31], ischemic changes, focal active colitis, and cryptitis (a personal observation). The amyloid type was AL (light chain protein) in the majority of the cases of the small intestine [6,16,21,23,24,34,40] and colorectum [16,18,20,21,23,24].…”

“…In the small intestine, the most common endoscopic findings were thickening of the intestinal wall (18%) [28][29][30][31][32]39], and polypoid mucosal protrusions (11%) [37][38][39], followed by mucosal ulceration (7%) [34,36], friability and nodularity of the mucosa (7%) [30,36], and wall perforations (3%) [33].…”

“…Abdominal pain and intestinal obstruction (33%) [6,28,29,31,[33][34][35][36] Rectal bleeding (37%) [15,[20][21][22][23], followed by abdominal pain (11%) [15,20] and anemia [18] Colonoscopic findings…”

Systemic AA-amyloidosis related to MPO-ANCA microscopic polyangiitis: A case report

“…Vasculitis can be classified by involved vessel size as large-vessel, medium-vessel, or small-vessel type. As vasculitis is not widely recognized as a cause of AA-amyloidosis, we carried out a Medline search that found a reported association between a large-vessel vasculitis (Takayasu's disease) and AA-amyloidosis [5][6][7][8][9], but rare for other types of vasculitis including MPA [22]. Oweity et al reported a case with necrotizing angitis of the small intestine accompanied by AAamyloidosis.…”

Clinical images: Primary systemic amyloidosis masquerading as necrotizing vasculitis

“…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).…”