Leukemia (Blood Cancer)

 

Hi everyone in this blog we'll talk about Necrosis and different types of necrosis.

Necrosis is the death of body tissue. It occurs when too little blood flows to the tissue. This can be from injury, radiation, or chemicals. Necrosis cannot be reversed. The condition is called gangrene when large areas of tissue die due to a lack of blood supply.

Types of necrosis.

Coagulative Necrosis.

The first in our list is Coagulative necrosis and this involves ischemia to any organ, in this type the cell outline is preserved but the inner components are damaged so we do see the cell cytoplasmic membrane but the internal components are heavily changed like nuclei that have disappeared or a cytoplasmic matter that is more receptive to die if we zoom out the entire organ will preserve its shape although it's going to be dead so we might see some change in color but the general overall shape will be preserved.

 

                                                                                            Liquefactive Necrosis.

This involves more bacteria and watery material we see it in bacterial abscesses and brain infarcts in this type Neutrophils will aggregate and release a lot of lysosomal enzymes these are digestive enzymes that will eat everything locally so we're left with a big goo or meshy component filled with dead cells a lot of debris and exudative material over time the body will filter out or suck in the watery components and so we're left with a significant cavity so the overall shape of the organ is not preserved early on we'll see some gooey material and later on we'll see a big hole.  

Caseous Necrosis.

This is of course notorious for TB infections and some fungi infections in this type the body will isolate an infecting organ such as TB cells and put them all in one place and then surround the entire infective organism with a big sphere made of macrophages so if we cut it open we will see a thick wall made of macrophages and protective cells and the inner material is made of dead cells a lot of TB or other infective organisms and a lot of debris.

                                                                                                               Fat Necrosis.

In this type we have fat cells that have simply died this can be the result of trauma or non-trauma, the non-trauma is most likely enzymatic trauma is most commonly affects areas that are very rich in fat such as the breasts and the non-traumatic mostly occurs in areas rich with enzymes such as the pancreas in any case dead fat tissue will release lipase and this lipase will continue to degrade more and more fat cells as they release more lipase and all this free fat will bind to calcium in a process known as saponification. So if we take a sample we will see some dead fat tissue which is evident by fat cells that don't have nuclei in the periphery we'll see some saponification which is basically calcium and that appears dark blue in HNE stains.

Fibrinoid Necrosis

In this type the wall of the blood vessels is damaged or exposed most commonly as a result of immune reaction and as the wall is exposed fibrin and other blood components will seep into the wall and cause it to be thicker so if we take a sample of an affected vessel we will see a thick wall that is very pinkish.

                                                                                         Gangrenous Necrosis.

This is simply the result of lack of blood most commonly affecting distal organs such as the fingers or toes in this area the distal organ will not have blood for a very long time and that will cause the organ to simply die so in a way it's an ischemic insult but it can also be the results of infection such as in diabetic foot with complicated ulcer and in this case, it's more of Liquefactive issue.

Avascular Necrosis.

Avascular necrosis is the death of bone tissue due to a lack of blood supply. Also called osteonecrosis, it can lead to tiny breaks in the bone and cause the bone to collapse. The process usually takes months to years. A broken bone or dislocated joint can stop the blood flow to a section of bone. Avascular necrosis is also associated with the long-term use of high-dose steroid medications and too much alcohol. Anyone can be affected. But the condition is most common in people between the ages of 30 and 50.

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