Systemic Mastocytosis : Lymph Node

Comments:
Lymph node involvement is seen in 50% of cases of systemic mastocytosis (SM) which is less frequent than involvement of bone marrow, liver, and spleen. Generalized lymphadenopathy is rare and is usually associated with aggressive forms such as aggressive systemic mastocytosis and systemic mastocytosis with hematological neoplasm.

The most frequent pattern is compact mast cell infiltrates in the paracortical areas. In the image shown here from a case of SM with lymph node involvement, the nodal architecture is totally effaced by widespread, small compact clusters of mast cells.