ICD-11 definition : Mastocytosis is due to a clonal, neoplastic proliferation of mast cells that accumulate
in one or more organ systems. Activating mutations of KIT are frequently found. It
is characterized by the presence of multifocal compact clusters or cohesive aggregates/infiltrates
of abnormal mast cells. The disorder is heterogeneous, ranging from skin lesions that
may spontaneously regress to highly aggressive neoplasms associated with multiorgan
failure and short survival. Subtypes of mastocytosis are recognized mainly by the
distribution of the disease and clinical manifestations. In cutaneous mastocytosis
(CM), the mast cell infiltration remains confined to the skin, whereas systemic mastocytosis
(SM) is characterized by involvement of at least one extracutaneous organ with or
without evidence of skin lesions. Mastocytosis should be strictly separated from mast
cell hyperplasia or mast cell activation states without morphological and/or molecular
abnormalities that characterize the neoplastic proliferation.;
Mastocytosis is due to a clonal, neoplastic proliferation of mast cells that accumulate
in one or more organ systems. Activating mutations of KIT are frequently found. It
is characterized by the presence of multifocal compact clusters or cohesive aggregates/infiltrates
of abnormal mast cells. The disorder is heterogeneous, ranging from skin lesions that
may spontaneously regress to highly aggressive neoplasms associated with multiorgan
failure and short survival. Subtypes of mastocytosis are recognized mainly by the
distribution of the disease and clinical manifestations. In cutaneous mastocytosis
(CM), the mast cell infiltration remains confined to the skin, whereas systemic mastocytosis
(SM) is characterized by involvement of at least one extracutaneous organ with or
without evidence of skin lesions. Mastocytosis should be strictly separated from mast
cell hyperplasia or mast cell activation states without morphological and/or molecular
abnormalities that characterize the neoplastic proliferation.