Histologic changes

This lesion originates from a large muscular artery (lower left). At the center is a compact mass of angioblastic tissue or granulation tissue (plexiform lesion). The endothelial cells are prominent. Stroma has the bluish tinge of new matrix. The vascular lumens contain fibrin thrombi that organize as remodeling continues. Microangiopathic, hemolytic anemia and thrombocytopenia have been associated with these lesions [1].

At the periphery of the plexiform lesion are enlarged, angiomatous channels of the dilation lesion (arrows). Note the extension into adjacent capillary walls.


1. Jubelirer S. Primary pulmonary hypertension. Its association with microangiopathic hemolytic anemia and thrombocytopenia. Arch Intern Med 1991; 151:1221-1223.

Clinical summaryImage 3

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