Childhood mastocytosis: Update
- Cutaneous mastocytosis in children is the most common form of mastocytosis
- True systemic mastocytosis is very rare in children
- An NIH study of 105 children found 30-65% improved over time
- Elevated baseline tryptase level and organ swelling were good indicators of SM
- Serum tryptase should be measured every 6-12 months
- Children with swelling of both liver and spleen were positive for CKIT D816V mutation
- Swelling of liver and spleen together was linked to disease persisting into adulthood
- Most children with UP with skin and minor GI issues had normal tryptase
- Diffuse cutaneous mastocytosis patients had a much higher average tryptase but no organ swelling
- Serum tryptase and IgE were inversely related (high tryptase with low IgE, low tryptase with high IgE)
Chronic mast cell leukemia: a new variant of systemic mastocytosis
- Mast cell leukemia (MCL) has a significantly shortened lifespan
- Usually over 20% of nucleated cells in bone marrow are atypical mast cells
- Mast cells are present in large quantities on the blood
- Cases where less than 10% of white blood cells in blood are mast cells are called aleukemic variant MCL
- Cases where over 20% of nucleated cells in bone marrow are mature mast cells are called chronic MCL
- Chronic MCL patients do not have any C findings (the clinical markers for SM patients associated with very aggressive disease)
- Chronic MCL patients have stable disease state but can progress to acute MCL at any time
- Mediator release symptoms are more common in chronic MCL than acute MCL
- Acute MCL is marked by immature CD25+ mast cells
- Acute MCL patients do have C findings (the clinical markers for SM patients associated with very aggressive disease)
- Acute MCL has a very short survival time, usually less than a year