Two cases of cardiac arteriovenous malformation complicated by a local angioproliferative process

Abstract

Vascular malformations of the heart are extremely rare with only a few cases of the arteriovenous type of vascular malformation (AVM) reported. We investigated the pathology of two additional cases, which were complicated by the occurrence of a local vasoproliferative response of immature but benign vessels. We suppose that the mass forming effect of this vasoproliferative response, which has also been reported recently as a complication of congenital AVM elsewhere in the body, has significantly contributed to the onset of symptoms and ultimate death of both patients.

Fig. 1

Patient no. 1. a Endomyocardial biopsy specimen showing diffuse spread of capillary vessels amidst myocardium (haematoxylin and eosin stain). b Immunostain with anti-CD31 antibody outlines the endothelium of the immature vessels. c Immunostain with anti-Ki-67 shows nuclear positivity in some vascular wall cells. d Midventricular transverse section through the heart showing biventricular endocardial fibroelastosis and cystically dilated vessels. e Elastica von Gieson-stained section of myocardium showing closely apposed artery and vein (with recanalized thrombus [arrow]) of the vascular malformation

Fig. 2

Patient no. 2. a Midventricular transverse section of the heart showing anteroseptal hypertrophy with congested hypervascular areas. b and c Histology (overview and details) showing large dilated and congested vessels surrounded by closely packed microvessels and sparse remaining cardiomyocytes (arrows). d and e Areas of myocardial disarray in the area affected by the vascular process and in adjacent nonaffected myocardium, respectively (b and e haematoxylin and eosin stain)