I have 2 patients referred by GI for "mastocytic colitis". The 1st patient was asymptomatic 55 year old male and had >20 mast cells per high power field(Hpf) on screening colon biopsy.


The 2nd patient is a 35 yr old female with severe constipation and abdominal pain with colon biopsy showing >20 mast cells per hpf on transverse and right colon, but no mast cells in the left colon. Her pain is mainly right sided. Both pathology reports said final diagnosis: mastocytic colitis.


No eosinophils found on biopsy in either case.


The 2nd patient responded to laxatives but is still not regular (not complete control).


I have tried to do some research on mastocytic colitis but have not found much at all.


My questions are:
1) What are the symptoms of mastocytic colitis and when is it appropriate to order further testing?
2) In these cases, are the mast cells just incidental findings?
3) Would you order a serum tryptase, 24 hr histamine, 24 hr VMA collections, food allergy testing?
4) would gastrocrom or H1/H2 blockers be helpful in the 2nd case?


I researched the ask the expert questions and have not seen any questions related. Thanks.


Thank you for your recent inquiry.

I am only aware of three articles in the literature dealing with mastocytic colitis. For your convenience, I have copied abstracts from two of these below. The third article, which will be the most salient for you, does not have an abstract. It is the article by Ogilvie-McDaniel, et al., which appeared in the Annals of Allergy, Asthma, and Immunology in 2008 (reference copied below). This article puts the first two articles into perspective from the standpoint of an allergist/immunologist seeing such a patient.

There is also a review article which mentions this condition that appeared more recently in Gastroenterology and Hepatology. The reference is also copied below. This article is available without charge online.

As mentioned, I believe that the article in the Annals will put things into perspective for you. However, as you will see from this literature, there are no definitive answers to your questions. Nevertheless I will try and answer your questions.

The major and most common manifestation of mastocytic colitis is diarrhea. Patients usually present to a gastroenterologist with this complaint.

We do not know whether or not these mast cells are incidental findings, but based upon the consensus expressed in these articles, they are rather considered active in the pathogenesis of the disease. The authors of these publications have felt that they were describing a new entity where mast cells were operative in the production of the symptoms.

It is very rare for systemic mastocytosis to present this way, but a serum tryptase, in my opinion, is indicated. If elevated, then you would pursue a diagnosis of systemic mastocytosis. One may also order a 24 hour urinary histamine metabolites (not histamine per se), but the serum tryptase is far more well documented as a test to search for systemic mastocytosis. You need not order 24 hour urinary VMA collections, and there is no evidence to support allergy testing in this condition. 

Again, from the references noted above you will note that Gastrocrom plus H1 and H2 blockers have all been reported, in various cases, to be helpful.

Thank you again for your inquiry and we hope this response is helpful to you.

Arch Pathol Lab Med. 2006 Mar;130(3):362-7.
Mastocytic enterocolitis: increased mucosal mast cells in chronic intractable diarrhea.
Jakate S, Demeo M, John R, Tobin M, Keshavarzian A.
Department of Pathology, Rush University Medical Center, Chicago, IL 60612, USA. shriram_jakate@rush.edu
CONTEXT: In some adult patients with chronic intractable diarrhea, the diagnosis remains elusive even after detailed evaluations, and colonic or duodenal biopsy specimens may appear unremarkable on routine hematoxylin-eosin staining.

OBJECTIVES: To assess the concentration of mast cells in colonic or duodenal biopsy specimens by immunohistochemical analysis for mast cell tryptase from patients with chronic intractable diarrhea and to evaluate their response to drugs affecting mast cell function.

DESIGN: Mast cells per high-power field were assessed in biopsy specimens from 47 patients with chronic intractable diarrhea, from 50 control subjects, and from 63 patients with other specific diseases that cause chronic diarrhea (inflammatory bowel disease, celiac disease, collagenous colitis, and lymphocytic colitis). Patients with chronic intractable diarrhea who had more than 20 mast cells per high-power field were administered drugs affecting mast cell mediator function and release.

RESULTS: The mean +/- SD concentration of mast cells in the 50 control subjects was 13.3 +/- 3.5 cells per high-power field; hence, patients with more than 20 mast cells per high-power field were considered to have increased mast cells. Thirty-three (70%) of 47 patients with chronic intractable diarrhea had increased mast cells, and symptoms were controlled by drug therapy in 22 (67%) of the 33 patients. No patient had systemic or cutaneous mastocytosis. No increase in mast cells was seen in patients with other common causes of chronic diarrhea.

CONCLUSIONS: In chronic intractable diarrhea, colonic or duodenal biopsy specimens may appear unremarkable on routine hematoxylin-eosin staining, but increased mast cells may be demonstrated by immunohistochemistry for mast cell tryptase, with the novel term mastocytic enterocolitis describing this condition. Similar increases in mast cells are not apparent in control populations or in patients with other specific diseases that cause chronic diarrhea. The cause of the increased mast cells remains to be elucidated 

Jackie D. Wood: Enteric neuroimmunophysiology and pathophysiology, Gastroenterology
Volume 127, Issue 2 , Pages 635-657, August 2004

Minute-to-minute behavior of the bowel, whether it is normal or disordered, is determined by integrative functions of the enteric nervous system (ENS). Information input processed by the ENS is derived from local sensory receptors, the central nervous system, and immune/inflammatory cells including mast cells. Enteric mast cells use the power of the immune system for detection of antigenic threats and for long-term memory of the identity of the specific antigens. Specific antibodies attach to the mast cells and enable the mast cell to detect sensitizing antigens when they reappear in the gut lumen. Should the sensitizing antigen reappear, mast cells detect it and signal its presence to the ENS. The ENS interprets the mast cell signal as a threat and calls up from its program library secretory and propulsive motor behavior that is organized to eliminate the threat rapidly and effectively. Operation of the alarm program protects the individual, but at the expense of symptoms that include cramping abdominal pain, fecal urgency, and diarrhea. Enteric mast cells use immunologic memory functions to detect foreign antigens as they appear and reappear throughout the life of the individual. Mast cells use paracrine signaling for the transfer of chemical information to the neural networks of the ENS. Integrative circuits in the ENS receive and interpret the chemical signals from the mast cells. Signals from the mast cells are interpreted by the ENS as a labeled code for the presence of a threat in the intestinal lumen.

Ann Allergy Asthma Immunol. 2008 Dec;101(6):645-6.
Mastocytic enterocolitis: a newly described mast cell entity.
Ogilvie-McDaniel C, Blaiss M, Osborn FD, Carpenter J.

Gastroenterol Hepatol (N Y). 2010 Dec;6(12):772-7.
Mast cells in gastrointestinal disease.
Ramsay DB, Stephen S, Borum M, Voltaggio L, Doman DB.

Phil Lieberman, M.D.


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