Caseous necrosis- Its Causes, Mechanism and Pathology

For medical students, it is very important to learn the process of cell death which has a medical term named Necrosis. Process of cell death happens due to many reason and could have severe consequences sometimes death even. I have already wrote an article on the types of Necrosis but we didn’t generalize it. Today, I am going to do two tasks on the topic. 1st one is to explain the Necrosis and its general concept and 2nd is to determine the most important type of necrosis which is Caseous Necrosis. I hope that at the end of this post you will have a good idea on both necrosis and its major type. We will go through almost everything such as definitions, causes, pathology, etymology, pronunciation, and some other type related to it. You will be allowed to ask the questions in the comments section at the end of this post since after study, questions do appear in the minds of students. Since I have already said that to understand the types we will need to start from necrosis and its general idea because without it, it is not fully possible to understand the topic further so let’s start with it.

What is Necrosis:

Necrosis is a special of kind of injury in the cells in which the cells of the body die prematurely and this cause severe consequences. We can also say that it is the death of all living tissues in a particular part or parts of body we then later, leads that area to dis-function or complete loss. Consequences vary according to the different types as we start moving ahead but first you just need to have a general concept of it. There are not just one but several factors that causes this type of disease or problem to occur.

This cell death can be caused by several things. Some of the main reasons are infections, trauma, toxins and various other injuries that had blown a particular area in such a way that the tissues started dying and that will lead to the organ demise. Unlike apoptosis, necrosis work due to the activation of various receptors present in the body which leads to the cell death in that particular area where you got infected, injured or any other reason for the problem. When these receptors are activated, the integrity of the cell membrane loses which means that it is no longer able to perform its functions correctly. When this happens, the extracellular space is gets filled with the products of the cell death which were released due to their uncontrolled flow.

After this uncontrolled flow the affected area loses its value since all the cells are dead which later causes its loss. This tissue is then later removed by the surgeon through surgery since due to many factor it is unable to be removed automatically from the body. It is important to treat this problem because if you won’t do it, it results in the formation of cell debris around the dead tissue. I guess, now you have a good general idea of the necrosis. It is time to move on to our major objective which is the study of the most important type which is caseous necrosis.

What is Caseous Necrosis:

There are several reasons due to which this is considered as the most important type of necrosis. This basically is a type of coagulative necrosis and is named due to its appearance. You’re going to read the definitions, causes, morphology and also the treatment options that you can use to treat this type of necrosis and get rid of it.


In this type of cell death the tissue appears like a cheese shape type thing. It gives this grassy cheesy appearance due to which this is named as Caseous necrosis. As I have already mentioned that it is a type of coagulative necrosis that’s why we also need to understand the concept of that as well. Coagulative necrosis is the type of the cell death which is mainly causes by some major reasons such as infarction or ischemia. Caseous necrosis mostly happens which a patient has tuberculosis and that is the main factor that causes this problem. This can also be described as a sweet combination of coagulative and liquefactive necrosis

what is caseous necrosiscaseous necrosis in lymph nodes

Causes of Caseous Necrosis:

This type of necrosis is meant to happen due to two main reasons. These reasons include mainly TB or Tuberculosis and also syphilis and come other certain types of fungi are held responsible for this type of cell death to occur. When a patient is suffering from tuberculosis he will likely show this type of cell death since the infection readily effects his cells and will result in the cell death in the living tissue. Syphilis and then there are some other types of fungi that are responsible for the type of necrosis under discussion.

Since this is a sub-type of coagulative and is also described as the combination of two types of necrosis such as liquefactive and coagulative, so the reasons behind these two types can also be the reasons for caseous necrosis as well. These reasons could be ischemia or infarction if the causes of cogulative are behind this to happen. Focal bacteria or some other bacterial infections could also be the reasons if we take causes of liquefactive necrosis. This gives the type of necrosis a grassy cheesy look which is the main reason behind the naming of this type as well.

Caseous Necrosis Pronunciation:

Pronunciation of this word is quite confusing for some people. That is because they try to pronounce it with the sound of SC or SH which is wrong. The word ‘Caseous’ should be pronounced as the word flow of word ‘Case’ and then ‘OUS’. While Necrosis is quite easy to pronounce where you simply need to pronounce C as K and you are done with the rest. To remove the confusion in ‘CASEOUS’ you can refer to this video. In the video you can hear exactly as the term is really pronounced.

Pathology of Caseous Necrosis:

Though the pathology of this types of necrosis is already explained in the paragraphs behind but I felt the need to present it separately since in there, it is quite mixed with other content.
In the case of tuberculosis, the hilar lymph node gets infected by it and that is when the caseous necrosis happens. It appears like a cheesy material and that is the reason behind the naming of this necrosis. This grassy cheesy appearance gives it a strange long and that’s why medical experts named it caseous necrosis according to how it appears.


For the greater understanding of the topic, it is also important that we study the mechanism of it. After studying the mechanism you can claim that you have a very good grip on this type of necrosis and you are ready to explain and give tests for it. Mechanism is how this thing appears and how does it look like. There are different steps in the mechanism of caseous necrosis that you really need to understand and don’t worry because here, they are explained in easy steps along with easy wordings so let’s get going.

1. Macrophages:

These are the first thing in the mechanism of this type of necrosis. Ingestion of various microorganisms is caused by the special kind of activity known as phagocytic activity which is the basic thing in the macrophages. These macrophages are not as effective as they may look. There a lot of types of organism which they can’t kill and that’s why they are something that can’t be relied on. The best they do is the engulfing of these organism and then let them to be presented to the next thing in the mechanism which is T lymphocytes.

2. T lymphocytes:

Now this is the one which performs some important function. That’s why it is called sole warrior in the mechanism of the caseous necrosis. Here is what it does.

After the activation of T lymphocytes, different types of cytokines are produced. These cytokines mainly included interleukin 2 and interferon gamma which as a medical student you must know that how important they are and what role they play. Macrophages which weren’t very useful before, they now get activated by these lymphocytes. Epithelial cells are the next form they get transformed into. Following is what happens next after the mentioned happening.

Then comes the formation of multi-nucleated giant cells. These giant cells are produced by the fusion of Epitheloid cells. Macrophages which were playing an important role now, some of them could die in all of this happening. In this they are not completely useless since they contribute to the necrosis in the larger areas. This happens when they release their lysosomal enzymes and this could be the last of contributions which macrophages can make after their death. Cell mediated immunity is the term given to this types of process which is a major part of the mechanism of caseous necrosis. This is explained in great detail in another of our articles.

3. Epitheloid Cells:

This kind if cell is completely different from the macrophages since their nucleus is less dense than a macrophage and also, they have pale pink granular cytoplasm. It plays a completely unique role if we talk about the mechanism of caseous necrosis. Its working is already mentioned in the 2nd heading of the mechanism which is T lymphocytes and after reading which you can realize its importance. Writing a separate reading only serves the objective of explaining what these cells are. They have ovalent or vesicular shape. They perform a secretory function but the phagocytic activity is something very less in them.

4. Multi-nucleated Giant cells.

Giant cell is the last and a major part of the mechanism of caseous necrosis. This results after a bigger fusion takes place. This fusion is of the epitheloid cells in greater numbers. In this type of fusion there are more than 20 types of nuclei involved and these are the reasons why this form such a giant molecule. You can see this in the case of tuberculosis when it forms a distinctive horse shoe type shaped and that’s of course after the fusion.

Some other types of Necrosis:

Here is the list of some other important types of necrosis. Read our separate post for detailed study about all types of necrosis.

1. Liquefactive Necrosis:

Mentioning this type of necrosis is important which liquefactive and coagulative combination forms the caseous necrosis. So the reason behind these types of cell death can also be the reasons behind our main topic. In this type of necrosis, the affected area forms a viscous mass in which the liquid is present. This happens due to many reasons and one of the main reasons is a severe injury. After you get a strong injury, the cells of the area gets affected and their death and accumulations causes this type of viscous mass. This also happens due to some other reasons such as various bacterial infections and focal bacteria that could be dangerous. They create severe reactions at the place thus, forming this type of necrosis.

2. Gangrenous Necrosis:

A regular blood supply to each and every part of the body is very important. All body parts work properly as long as the blood supply is good. But when it stops, then many problem can occur and one of those many problem is this types of necrosis called Gangrenous or Gangrene. This type of necrosis occur when these is insufficient supply of blood to the certain part of human body. This constituent a special form of necrosis which you can study in detail in our article types of necrosis.

Final Words:

In this detailed post, I guess you have learnt almost everything about Necrosis, Caseous Necrosis and its types. You also learned other different things related to it such as etymology, pathology and causes etc. Now you must have understood this topic very well and you can do quite well in getting good marks in your studies.
How much did you like this and how much did you learn from it? Do you have any queries related to the topic? You can do all of this by typing in your feedback in the section below and keep visiting our website.

Hi, This is Hamza Khan from Peshawar, Pakistan. I am a 2nd prof MBBS Student at Bannu Medical College and a hobby Blogger. The Purpose of this site is to share my knowledge and Guide new Medical Students.

2 comments On Caseous necrosis- Its Causes, Mechanism and Pathology

  • I’m just confused. So in cellular adaptation of the body, macrophage transforms into epithelioid cells which is activated by the lymphocytes, and then again forms a fusion of multi-nucleated giant cells after release of lysosomal enzymes until it defends the body from the invaders. Correct me if I’m wrong. So the origin of the forms of these cells are macrophage. In conclusion all of these cells are macrophage just in different forms? Is that right. Also, is there any treatment for this type of necrosis(caseous)?

    • yes right…this is also called delayed type of hypersensitivity reason. the best example is pulmonary tuberculosis and i hope you would know about the treatment of pulmonary TB.

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