Renal amyloidosis

What it means

A form of amyloidosis that affects the kidney. On hematoxylin and eosin stain, amyloid is identified as extracellular amorphous material that is lightly eosinophilic. These deposits often stain weakly for periodic acid Schiff (PAS), demonstrate a blue-to-gray hue on the trichrome stain and are typically negative on the Jones methenamine silver (JMS) stain. These tinctorial properties contrast with the histologic appearance of collagen, a major component of basement membranes, mesangial matrix and areas of sclerosis, which demonstrates strong positivity for PAS and JMS (See Figure 1 of PMID:25852856).

In the kidney, amyloid deposits may be found in any of the parenchymal compartments, including glomeruli, tubules, interstitium and/or vessels. Glomeruli are most commonly involved. In most instances, amyloid accumulation involves the mesangium before the capillary walls. In early cases, the process can be subtle and involves only a few mesangial regions and therefore can easily be missed by routine histologic evaluation. More extensive involvement results in marked expansion of the mesangium, which can take on a nodular appearance and mimic mesangial sclerotic processes such as diabetic glomerulosclerosis. However, the often negative staining with PAS and JMS is more typical of amyloid.

Rare diseases that can present with this8

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category