Figure 2.

Microscopic appearance of lesion. (A) The lesion is composed of numerous vascular channels, containing red cells and mixtures of hematopoietic cells. (B) The vascular component of the lesion consists of channels of varying caliber lined by benign-appearing endothelial cells. (C) and (D) The hematopoietic cells are mainly erythroid precursors with a smaller number of myeloid and megakaryocytic precursors mixed with numerous macrophages (larger foamy cells). (Hematoxylin and eosin; magnification: ×200 in A; ×600 in B through D.)