systemic mastocytosis is a rare disease with abnormal proliferation and infiltration of mast cells in the skin , bone marrow , and viscera including the mucosal surfaces of the digestive tract , liver , spleen , and lymph nodes .
the clinical course of these patients is variable ranging from asymptomatic for years to highly aggressive and rapidly devastating or even mast cell leukemia .
clinical manifestations of systemic mastocytosis reflect either mediator release from mast cells or infiltration of mast cells into tissues .
they include constitutional signs , skin lesions , mediator - related findings ( flushing , syncope , diarrhea , hypotension , headache , and/or abdominal pain ) , and musculoskeletal disease .
due to the rarity of the disease , there are few prospective studies of gastrointestinal ( gi ) involvement , so the actual frequency of upper and lower gi lesions is unknown .
hepatomegaly , portal hypertension , splenomegaly , and ascites occur frequently in patients with systemic mastocytosis . to the best of our knowledge ,
mast cell infiltration in the appendix due to systemic mastocytosis has not been described until to date . in this report
, we describe a case of systemic mastocytosis presenting as acute appendicitis , which has successfully been treated with laparoscopic appendicectomy .
histology revealed dense infiltrates of mast cell aggregates found in tryptase - stained biopsy sections with c - kit d816v positivity .
a 38-year - old caucasian female with systemic mastocytosis c - kit d816v ( + ) diagnosed in 2006 , who had been on symptomatic therapy with anti - histamines ( h1 and h2 blockers ) for pruritus , was admitted to the hospital for acute right - sided abdominal pain which become progressively worse after a duration of 24 h. the pain was constant and sharp in intensity and was not relieved with narcotics .
laboratory studies showed a normal white blood cell count of 8  10/l with eosinophilia of 1.6  10/l , a hemoglobin level of 11.2 g / dl and a platelet count of 253  10/l .
the serum tryptase level was elevated at 23 g / l ( normal value : 0.410.9 g / l ) .
a ct of the abdomen and pelvis noted an enlarged appendix of 12 mm in diameter , with minimal wall enhancement .
the appendix was found to be hyperemic and firm , and it was densely adherent to the posterior cecum , the surrounding peritoneal wall , and the overlying mesenteric fat .
histological exam of the appendix revealed acute appendicitis with mastocytosis ( greater than 30 mast cells per high - power field ) by immunoperoxidase studies with mast cell tryptase and cd117 ( fig . 1 , fig
mastocytosis is a disorder involving neoplastic proliferation of mast cells and their cd34 + precursors .
there are two major forms of mastocytosis : cutaneous mastocytosis , which is defined by the presence of one or more lesions limited to the skin ( the face , palms , and soles are usually not affected ) , and the systemic form of mastocytosis ( systemic mastocytosis ) , characterized by lesions affecting various internal organs , mainly the bone marrow and the gi tract , as well as the liver and spleen .
notably , a point mutation in position 816 of the receptor ( kit d816v mutation ) is found in up to 85% of all patients with systemic mastocytosis .
clinical symptoms in patients with mastocytosis are caused either by release of biological mediators from the mast cells and/or their accumulation in various organs of the body , the skin and the bone marrow being more commonly associated . in their review , jensen et al .  
have reported gi symptoms in 6080% of patients with systemic mastocytosis , rendering gi symptoms as common as pruritus in these patients .
the various gi manifestations reported in systemic mastocytosis are presented in table 1 . in this case report
abdominal pain is a very common gi manifestation in patients with systemic mastocytosis , and it has been reported in up to 80% of patients .
the abdominal pain is most frequently chronic and the major source of distress caused by the disease . in our case report
, the patient also suffered from chronic abdominal pain for the last 5 years , which was controlled with narcotics .
acute appendicitis resulting from mast cell infiltration has not been reported before and should be considered as a potential cause in patients with systemic mastocytosis presenting with acute worsening abdominal pain .
some studies suggest that mucosal inflammation may lead to mast cell infiltrates as part of an acute inflammatory response .
other studies indicate that mast cell degranulation in the lamina propria may directly interact with motor neurons and silent nociceptors leading to smooth muscle contraction , diarrhea , and abdominal pain . the initial clinical picture ( like in our patient )
may be confounded in this patient population since patients may experience chronic abdominal pain and may be on narcotics for pain control , which can mask the typical signs and symptoms of acute appendicitis .
after appendectomy , our patient was discharged on antihistamines and is asymptomatic after 5 months of follow - up .
we have reported the first case of histologic evidence of acute appendicitis due to mast cell infiltration in a patient with systemic mastocytosis .
since the majority of patients with abdominal complains have chronic abdominal pain and are on narcotics , it is important for the physician to identify patients with acute appendicitis .
 systemic mastocytosis is characterized by abnormal growth and accumulation of mast cells in various organs . 
 gastrointestinal ( gi ) symptoms are common disease manifestations in this disease and can significantly impair the quality of life . 
 signs of gi systemic mastocytosis include steatorrhea , malabsorption , hepatomegaly , splenomegaly , portal hypertension , and ascites . 
 acute appendicitis as a presenting feature in systemic mastocytosis has not been reported in the literature previously . in this report 
 , we discuss the case of a female patient with systemic mastocytosis ( c - kit d816v ( + ) ) who was admitted for right - sided acute abdominal pain . 
 laboratory study revealed an normal white blood cell count with eosinophilia and an elevated serum tryptase level of 23 g / l . 
 ct of the abdomen and pelvis showed an enlarged appendix of 12 mm in diameter , with minimal wall enhancement . 
 laparoscopic appendectomy was performed . 
 the appendix was found to be hyperemic and firm , and it was densely adherent to the posterior cecum , the surrounding peritoneal wall , and the overlying mesenteric fat . 
 pathology revealed acute appendicitis with greater than 30 mast cells per high - power field by immunoperoxidase studies with mast cell tryptase and cd117 . 
 the patient subsequently improved and was discharged home . 
 this case is the first reported case with a histological diagnosis of acute appendicitis resulting from mast cell infiltration . 
 physicians should be aware of acute appendicitis as a manifestation of systemic mastocytosis . 
 prompt diagnosis and management may prevent potentially fatal complications of appendiceal perforation and peritonitis . 
Introduction
Case Presentation
Discussion
Conclusion
Disclosure Statement