Colon non tumor
Nonneoplastic, noncongenital lesions

Author: Raul S. Gonzalez, M.D. (see Authors page)

Revised: 10 January 2017, last major update July 2013

Copyright: (c) 2003-2017,, Inc.

PubMed search: colonic amyloidosis

Cite this page: Amyloidosis. website. Accessed March 29th, 2017.
Definition / General
  • Extracellular deposition of amyloid protein, often around blood vessels
  • Localized (limited to the colon) or diffuse (present in numerous organs)
  • Can be primary, secondary, hereditary or endocrine related
  • Overproduction of amyloid protein (AL, AA, ATTR, etc.) due to various causes
  • Senile amyloid is often present in GI tract of elderly patients (Pathol Res Pract 1994;190:641)
Clinical Features
  • Gastrointestinal involvement is seen in most patients with systemic amyloidosis
  • May be asymptomatic or cause bleeding, obstruction, perforation or abnormal motility
  • Amyloid tumor may clinically resemble carcinoma (AJR Am J Roentgenol 2002;179:536)
  • Uncommonly, amyloid is localized to colon and does not require systemic treatment (Amyloid 2003;10:36)
  • Can diagnose with rectal biopsy that includes submucosa (85% sensitivity), though amyloid deposition may be initially discovered in a resection specimen
Radiology Description
Case Reports
  • If systemic, depends on type of amyloid, but generally targeted at the cause (myeloma, kidney failure, etc.)
Gross Description
  • Mucosa may be normal or finely granular
Gross Images

Images hosted on other servers:

Amyloid tumor (above)
and adenocarcinoma
arising from villous
adenoma (below)

Micro Description
  • Amyloid present in blood vessel walls and muscularis propria; may be subepithelial; may cause ischemic changes or frank hemorrhage
Micro Images

Images hosted on other servers:

Rectal biopsy

Submucosal vessel involvement

With Congo Red stain

Congo Red stain
highlights vessel
wall and free
submucosal amyloid

Congo Red stain

Subepithelial deposits
resembling collagenous colitis

Positive Stains
  • Congo Red (stains deep pink and demonstrates apple green birefringence, as in other body sites)
Differential Diagnosis
  • Collagenous colitis: surface epithelial damage, epithelial lymphocytes
  • Elastofibromatous change: lacks apple green birefringence on Congo Red, elastin stain positive
Additional References