Figure 1.

CD117 expression in patients with hereditary alpha tryptasemia compared to systemic mastocytosis. Panel A and C are representative hematoxylin and eosin (H&E) and CD117 stains of duodenum of a patient with systemic mastocytosis. Panel B and D are representative H&E and CD117 from duodenum of a patient with hereditary alpha tryptasemia (HαT). Mast cells are clustered, expanded in number, and spindle shaped in systemic mastocytosis. In HαT, CD117 positive mast cells are expanded in the lamina propria with slightly clustering and are increased in cell size. CD117 positive cells stain brown. Slides stained for CD117 are counterstained with hematoxylin. Bar length = 50 µm