Systemic mastocytosis (pronounced mass-toe-sigh-TOE-sis), or SM for short, is a rare disorder that causes the body to make too many abnormal mast cells. Mast cells are white blood cells that aid the immune system and help fight off illness. When these cells are activated, it can result in symptoms similar to an allergic reaction. A severe allergic reaction, known as an anaphylaxis, can cause severe inflammation and organ damage.

About Advanced Systemic Mastocytosis

Advanced Systemic Mastocytosis (AdvSM) is less common than Non-Advanced Systemic Mastocytosis (NonAdvSM) but represents a more serious form of the condition.

What makes advanced systemic mastocytosis different from non-advanced?

Advanced systemic mastocytosis involves mast cell accumulation that causes damage to major organs like your liver, spleen, bone marrow, or digestive system. Unlike NonAdvSM, AdvSM can affect organ function and may require more intensive medical management.

What are the three types of advanced systemic mastocytosis?

• Aggressive Systemic Mastocytosis (ASM) features organ damage or dysfunction from mast cell infiltration, affecting organs like the liver, spleen, or digestive tract.
  
  
• Systemic Mastocytosis with Associated Hematologic Neoplasm (SM-AHN) occurs when systemic mastocytosis develops alongside another blood disorder, requiring treatment for both conditions.
  
  
• Mast Cell Leukemia (MCL) is the rarest and most aggressive form, characterized by high numbers of abnormal mast cells in the bone marrow and blood.

What symptoms might I experience with advanced systemic mastocytosis?

In addition to symptoms seen in NonAdvSM, people with AdvSM often experience more severe fatigue, unexplained weight loss, low blood counts, bone pain and fractures, enlarged liver or spleen, and swollen lymph nodes. Some may also have difficulty absorbing nutrients.

Symptoms of Advanced Systemic Mastocytosis

Symptoms may include:

Fatigue

Nausea, malabsorption, and weight loss

Low blood counts

Bone pain and/or fractures

Abnormal liver function

Liver and/or spleen enlargement

Will advanced systemic mastocytosis affect life expectancy?

Advanced Systemic Mastocytosis can potentially affect life expectancy, although prognosis varies depending on the specific subtype and how well it responds to care. Early diagnosis and specialized treatment are particularly important for the best possible outcomes.

Why specialized care matters

Because AdvSM can affect multiple organ systems and may progress more rapidly than NonAdvSM, working with specialists experienced in treating mast cell disorders—particularly hematologists or oncologists—is crucial for optimal management.

How is advanced systemic mastocytosis monitored?

Regular monitoring typically includes blood tests to check organ function and blood counts, imaging studies to assess organ involvement, and bone marrow evaluations to track disease progression. Your healthcare team will determine the appropriate monitoring schedule for your specific situation.

What should I focus on if I have advanced systemic mastocytosis?

Prioritize building a specialized healthcare team, staying vigilant about new or worsening symptoms, maintaining open communication with your medical providers, and connecting with support resources that understand the unique challenges of living with a more serious form of systemic mastocytosis.