Systemic Mastocytosis: Causes, Symptoms, Treatment, Diagnosis

Systemic Mastocytosis is a pathological condition characterized by abnormal accumulation of mast cells in the tissues of vital organs of the body like the liver, spleen, bone marrow, and small intestine.

Systemic Mastocytosis is normally seen in adults. The symptoms of Systemic Mastocytosis are variable and depend on the organ that is affected by the condition.Systemic Mastocytosis is basically caused by mutation of the KIT gene which is responsible for various functions of the cells.

Majority of the cases of Systemic Mastocytosis are not inherited but are caused due to sporadic mutation of the KIT gene even though some familial cases have been reported of Systemic Mastocytosis. There are four main types of Systemic Mastocytosis. These are:

• Indolent systemic mastocytosis
• Systemic mastocytosis with associated hematologic non-mast cell lineage disorder
• Aggressive systemic mastocytosis
• Mast cell leukemia

It is important for an individual who has been diagnosed with Systemic Mastocytosis to identify the type of the condition as the treatment and the overall prognosis are different for different types of Systemic Mastocytosis.

As stated, the root cause for Systemic Mastocytosis is mutation in the KIT gene. This mutation is in most cases sporadic and does not follow any inheritance pattern. The function of the gene is to produce a protein responsible for various cellular processes and cell growth and division.

This protein is also responsible for development of mast cells which are immune cells which are necessary for inflammatory response by the body. The abnormal mutation of the KIT gene results in overproduction of the mast cells which then start to accumulate in the tissues of the various organs of the body leading to the symptoms of Systemic Mastocytosis.

The symptoms of Systemic Mastocytosis depend on which part of the body is affected by the mast cells, whether it is intestines, liver, spleen, or the bone marrow. Some of the symptoms which are common irrespective of the affected organs are:

• Anemia with associated bleeding disorders
• Abdominal pain
• Diarrhea
• Nausea with or without vomiting
• Itching
• Development of hives
• Flushing of the skin
• Hepatomegaly
• Splenomegaly
• Lymphadenopathy.

Systemic Mastocytosis is suspected based on the symptoms that the patient presents with. Various investigational studies may be done to rule out other conditions that may be causing similar symptoms.

Once all these conditions are ruled out then a confirmatory diagnosis is made of Systemic Mastocytosis. Some of the tests done to diagnose Systemic Mastocytosis are:

• Bone Marrow Biopsy: This is perhaps the best test in order to confirm the diagnosis of Systemic Mastocytosis.
• Blood Studies: Blood studies will clearly show anemia, elevated WBCs, hypoalbuminemia which are all tell tale signs of Systemic Mastocytosis.
• Radiological studies like an ultrasound or an MRI may help in determining the extent and severity of the disease process.
• Once the affected organ is identified a biopsy of the organ can be conducted to look for the type and extent of Systemic Mastocytosis.

The treatment for Systemic Mastocytosis depends on the symptoms of the patient and the type of Systemic Mastocytosis. Some of the medications that are used to treat Systemic Mastocytosis are antihistamines for skin and gastrointestinal symptoms, PPIs for increased acid in the stomach.

In cases of anaphylaxis due to complication of Systemic Mastocytosis, epinephrine may be utilized. Steroids may be given to treat malabsorption. In case if the condition is malignant then steroids along with chemotherapy will be given to treat Systemic Mastocytosis.