The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 47

  1. 58. What is mastocytic enterocolitis?

A high powered field (hpf) is what you see through a microscope when you use powerful magnifying lenses. With very few exceptions, high powered fields using the same lenses are the same size. Since they are the same size, you can directly compare results from various groups all over the world.

In 2006, a paper was published that coined the term “mastocytic enterocolitis”. The author described mastocytic enterocolitis as more than 20 mast cells per high powered field. This paper was about people with severe chronic diarrhea that did not improve with treatment. The author found that healthy people had about 13 mast cells/hpf while people with severe chronic diarrhea had about 20 mast cells/hpf. The author felt that the extra mast cells were responsible for the diarrhea and inflammation so they called the extra mast cells in the colon and the small intestine “mastocytic enterocolitis”. Enterocolitis is the term for inflammation in the small intestine and colon.

The author felt that 20 mast cells/hpf was the cutoff between a normal amount of mast cells in the GI tract and an abnormal amount. Under 20 was considered normal while 20 and above was considered abnormal. However, there have been a number of papers since that look at how many mast cells are present in the GI tract for patients with different conditions as well as healthy people. There are several conditions that can cause you to have 20 or more mast cells/hpf. (I wrote an exhaustive series on this in 2015-2016. Links are below.)

Additionally, in some situations, people have over 20 mast cells/hpf without having any symptoms. Sometimes healthy people without any GI conditions have over 20 mast cells/hpf. For this reason, there is not agreement about how many mast cells in the GI tract is too many. (If you’re looking for my opinion, I think the number for what is too many is around 25-30/hpf. This is just my opinion.)

In the last several years, some doctors have begun linking mastocytic enterocolitis to mast cell disease. This makes sense because we know that in those people, mast cell inflammation drives GI symptoms and damage. Mast cell patients certainly have a lot of inflammation in the GI tract so having extra mast cells there makes sense. Some experts think that mastocytic enterocolitis is a sign of mast cell activation syndrome and that patients with mastocytic enterocolitis all have mast cell activation syndrome.

Mastocytic enterocolitis is absolutely a real phenomenon. In these people, mast cells cause a lot of GI symptoms and damage the GI tract. Experts have not all agreed upon whether or not everyone with mastocytic enterocolitis has mast cell disease. Also, there are some researchers that feel that mastocytic enterocolitis is actually its own mast cell disease rather than just a feature of another mast cell disease like mast cell activation syndrome.

Currently, mastocytic enterocolitis is not recognized by the WHO as its own disorder. However, that could certainly change. It was only last year that MCAS was recognized by the CDC even though it was routinely recognized by researchers and providers. (Author’s note: This was initially published stating that the WHO recognized MCAS, rather than the CDC. MCAS has not yet been recognized by the WHO. This is a whopper mistake on my part. Many thanks to the reader who saw this. Sorry!) I personally expect this to change in the next few years as more mast cell patients are diagnosed and mastocytic enterocolitis is better recognized. I think it is suggestive of mast cell disease but I also think providers need to eliminate other possible causes for the extra mast cells in the GI tract.

For more detailed information, please visit these posts:

Mast cells in the GI tract: How many is too many? (Part One)

Mast cells in the GI tract: How many is too many? (Part Two)

Mast cells in the GI tract: How many is too many? (Part Three)

Mast cells in the GI tract: How many is too many? (Part Four)

Mast cells in the GI tract: How many is too many? (Part Five)

Mast cells in the GI tract: How many is too many? (Part Six)

Mast cells in the GI tract: How many is too many? (Part Seven)

Mast cells in the GI tract: How many is too many? (Part Eight)