MAST CELL DISEASES
Mastocytosis occurs from birth
to adulthood; adult-onset cases are more severe.
The WHO separates mastocytosis
into 3 categories:
Cutaneous mastocytosis, seen in children, regresses
over time. Mast cell degranulation enzymes (histamine and tryptase) cause
Systemic mastocytosis is a clonal proliferation of
mast cells associated with a KIT mutation; ≥1 organs are involved, as are the
skin and bone marrow. The WHO now classifies systemic mastocytosis as one of
the myeloproliferative neoplasms.
Variants include some rare leukemias.
Diagnosis is made with bone marrow biopsy and
Localized extracutaneous mast cell neoplasms can be benign (mastocytoma)
or malignant (sarcoma).