Overview of Neo-Vascular Lesions after Delivery or Miscarriage

Abstract

The concept of intrauterine neo-vascular lesions after pregnancy, initially called placental polyps, has changed gradually. Now, based on diagnostic imaging, such lesions are defined as retained products of conception (RPOC) with vascularization. The lesions appear after delivery or miscarriage, and they are accompanied by frequent abundant vascularization in the myometrium attached to the remnant. Many of these vascular lesions have been reported to resolve spontaneously within a few months. Acquired arteriovenous malformations (AVMs) must be considered in the differential diagnosis of RPOC with vascularization. AVMs are errors of morphogenesis. The lesions start to be constructed at the time of placenta formation. These lesions do not show spontaneous regression. Although these two lesions are recognized as neo-vascular lesions, neo-vascular lesions on imaging may represent conditions other than these two lesions (e.g., peritrophoblastic flow, uterine artery pseudoaneurysm, and villous-derived malignancies). Detecting vasculature at the placenta-myometrium interface and classifying vascular diseases according to hemodynamics in the remnant would facilitate the development of specific treatments.

Keywords: arteriovenous malformations; neo-vascular lesion; placental polyps; retained products of conception.

Figure 1

Findings of color Doppler ultrasound: Hypervascular appearance with turbulent flow. The hypervascularity was limited to the point of contact between the remnant and the myometrium, and there was no pulsatile perfusion in the remnant itself.

Figure 2

Findings of angiography: Abnormal engorgement in the arterial phase, with a thick venous phase visualized only 2 s later. This indicated the presence of an arteriovenous shunt. There was no pulsatile arterial perfusion in the remnant itself, where the contrast agent simply appeared to be leaking.