Amyloidosis

Published on 19/07/2015 by admin

Filed under Radiology

Last modified 19/07/2015

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 May be systemic (involving multiple organs in 80%) or localized (in single organ or tissue in 20%)

image Primary: Due to monoclonal plasma cell dyscrasia (associated with no other underlying disease)
image Secondary: Develops in setting of a number of different chronic inflammatory diseases

IMAGING

• CT findings

image Acute disease: Enlarged kidneys
image Chronic disease: Small kidneys with cortical thinning
image Bowel wall thickening, distension, intramural hemorrhage, and intussusceptions

– Wall thickening can be focal or diffuse ± calcification
image Hepatosplenomegaly

– Patchy or diffuse hypoattenuation ± calcification
image Retroperitoneal soft tissue infiltration ± calcification resembling retroperitoneal fibrosis
• MR findings

image Focal amyloid involvement may be low signal on T2WI
• Fluoroscopic findings

image Stomach: Thick folds (which may appear nodular or mass-like) ± calcification
image Small intestine: Symmetrical thickening of folds, impaired motility, and slow transit
image Colon: Luminal narrowing, loss of haustrations, and thickened transverse folds

CLINICAL ISSUES

• Symptoms depend on site of protein deposition
• Most common sites are kidneys, heart, liver, and GI tract
• Renal failure due to amyloid deposition in kidneys is most common cause of death (50%)
• GI tract involvement: GI bleeding, intestinal dysmotility, malabsorption, and protein-losing gastroenteropathy
image
(Left) Axial NECT shows an abnormally hypodense and mildly enlarged liver and spleen in this patient with biopsy-proven primary amyloid of the liver.

image
(Right) Spot film from a small bowel follow-through shows diffuse fold thickening image throughout the jejunum. This is a very nonspecific finding, one that required biopsy for the diagnosis of amyloidosis.
image
(Left) Axial CECT in a patient with amyloidosis demonstrates rind-like soft tissue thickening image surrounding the left kidney with internal calcification image.

image
(Right) Coronal CECT in the same patient demonstrates similar thickening image and calcification image surrounding the left kidney, as well as a more focal soft tissue mass image (amyloidoma) in the adjacent retroperitoneum.

TERMINOLOGY

Synonyms

• Systemic amyloidosis

Definitions

• Group of diseases characterized by deposition of abnormal protein (amyloid) in various tissues

image May be systemic (involving multiple organs in 80%) or localized (in single organ or tissue in 20%)
image Classified based on type of protein being deposited

– 30 different amyloidogenic proteins in humans
• Primary: Due to monoclonal plasma cell dyscrasia (associated with no other underlying disease)
• Secondary: Develops in setting of a number of different chronic inflammatory diseases

IMAGING

General Features

• Best diagnostic clue

image Small bowel wall thickening and hypomotility in patient with underlying chronic illness
• Location

image Small intestine, stomach, colorectum, esophagus, liver, kidney, heart
• Morphology

image Nonspecific small bowel fold thickening and hypomotility

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