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Guilherme Mazui

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What is the Difference Between Mastocytosis and MCAS?

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The main difference between mastocytosis and mast cell activation syndrome (MCAS) lies in the nature of the mast cell involvement and the presence of clonal proliferation.

Mastocytosis is characterized by the proliferation of mast cells, which can infiltrate the skin or other tissues and organs. It encompasses a heterogeneous collection of disorders, including cutaneous mastocytosis (CM) and systemic mastocytosis (SM). The diagnosis of mastocytosis is confirmed when one major criterion and at least one minor criterion are met, such as the presence of multifocal, dense aggregates of mast cells in bone marrow or other extracutaneous organs.

MCAS, on the other hand, is a condition where there is increased and inappropriate activation of mast cells without clonal proliferation. MCAS is characterized by repeated episodes of anaphylaxis-like symptoms, such as hives, swelling, low blood pressure, difficulty breathing, and severe diarrhea. The episodes are called "idiopathic" because the underlying trigger for mast cell activation is usually absent. Diagnosis of MCAS involves determining whether the symptoms occur in separate attacks, if mast cell mediators increase during the episode, and if there is improvement with treatment using inhibitors or blockers of mast cell mediators.

In summary, mastocytosis is a disorder characterized by the proliferation and infiltration of mast cells, while MCAS is a condition marked by the increased and inappropriate activation of mast cells without clonal proliferation.

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  • What is the Difference Between Mastocytosis and MCAS?
  • Comparative Table: Mastocytosis vs MCAS

    • Comparative Table: Mastocytosis vs MCAS

    Here is a table comparing the differences between mastocytosis and mast cell activation syndrome (MCAS):

    Feature Mastocytosis Mast Cell Activation Syndrome (MCAS)
    Definition A collection of disorders characterized by mast cell proliferation with infiltration of skin or other tissues and organs. A group of disorders characterized by the presence of pathological mast cells in organs and the absence of clonality.
    Diagnosis Diagnosis of mastocytosis is confirmed when one major criterion and at least one minor criterion are met, which include the presence of multifocal, dense aggregates of > 15 mast cells in bone marrow or other extracutaneous organs, and other specific criteria. Diagnosis of MCAS is based on the presence of typical clinical signs and symptoms, as well as exclusion of other disorders.
    Mast Cell Clonality Mastocytosis often involves clonal mast cell proliferation. MCAS can present as idiopathic mast cell activation syndrome, where mast cell clonality is absent and the underlying trigger for mast cell activation is usually absent.
    Subtypes Mastocytosis can be broadly categorized as cutaneous mastocytosis (CM) or systemic mastocytosis (SM). MCAS can be classified as primary clonal (including systemic mastocytosis and its cutaneous subtype) or secondary MCAS, where an underlying nonneoplastic disease is present.
    Symptoms Symptoms of mastocytosis can vary depending on the subtype and can include skin lesions, bone pain, and systemic manifestations. Symptoms of MCAS are often similar to those observed in patients with mastocytosis, including tachycardia, syncope, urticaria, flushing, nausea, vomiting, and brain fog.
    Treatment Effective therapy for mastocytosis often involves antihistamines and mast cell membrane-stabilizing medications. Treatment for MCAS may also involve antihistamines and mast cell membrane-stabilizing medications, as well as addressing underlying triggers.
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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.