Table 2.

Mastocytosis types and subtypes.

Cutaneous mastocytosis

Urticaria pigmentosa/Maculopapular cutaneous mastocytosis

Monomorphic

Polymorphic

Diffuse cutaneous mastocytosis

Cutaneous mastocytoma

Isolated mastocytoma

Multilocalized mastocytoma

Systemic mastocytosis

Bone marrow mastocytosis

Indolent systemic mastocytosis

Smoldering systemic mastocytosis

Aggressive systemic mastocytosis

Systemic mastocytosis with an associated haematologic neoplasm

Mast cell leukemia

Mast cell sarcoma

Note: Well-differentiated systemic mastocytosis (WDSM) represents a morphologic variant that may occur in any SM type/subtype, including mast cell leukaemia.