Hypervascular retained product of conception: Characteristic magnetic resonance imaging and possible relationship to placental polyp and pseudoaneurysm

Abstract

The cases of two patients who developed myometrial vascularization following dilatation and curettage are described. In case 1, pathological diagnosis was possible with the resected specimens. This patient had hypervascular retained products of conception (RPOC). In case 2, the natural course of this pathological condition was observed, confirming a process of regression during repeated withdrawal bleeding. The three principal magnetic resonance imaging (MRI) findings in these cases were: (i) presence of a remnant; (ii) breaking of the junctional zone in contact with the remnant; and (iii) vascularization/flow voids infiltrating into the myometrium from the broken junctional zone. These three MRI findings differed in degree and varied in combination in each case of RPOC. Uterine artery pseudoaneurysms have been reported as intrauterine vascularization after abortion or delivery with subsequent spontaneous regression. These reports may include cases of hypervascular RPOC.

Accuracy of Flow-void Diameters on MR Images in Diagnosing Uterine Arteriovenous Malformations in Patients With Pregnancy-related Diseases

“…In our study, MRI examinations were performed for patients with RPOC, CSP, and GTD. The ow void sign, such as multiple dotlike, tubular structures or multiple serpentine with low signal intensity on both T1WI and T2WI, could be found in patients with uterine AVMs in the myometrium and parametrium, which is consistent with the ndings of several previous studies [20,24,28,29,30,31] . Additionally, in clinical practice, we found that the ow void sign can also be observed in patients without uterine AVMs, and there was no signi cant difference between patients with and without AVMs (P > 0.05).…”

“…As previously described [24,28,29,30,31] , the ow-void sign was de ned as multiple dotlike, tubular structures or multiple serpentine with low signal intensity located within the myometrium and parametrium on both T1WI and T2WI in our study.…”

“…However, in contrast to previous reports, our data mainly focused on pregnancy-related diseases coexisting with uterine AVMs, including RPOC (26/36), CSP (8/36) and GTD (2/36). RPOC and CSP are the most common aetiologies for acquired uterine AVMs [30,34,35,36] . In patients treated for CSP, gestation that is left in place could be considered an RPOC and can present a risk for the development of AVMs [14] .…”

“…Additionally, in clinical practice, we found that the ow void sign can also be observed in patients without uterine AVMs, and there was no signi cant difference between patients with and without AVMs (P > 0.05). Nevertheless, most previously reported uterine AVMs on MRI have focused on the morphological characteristics of the ow void sign [24,28,30,31] , and the available studies have been limited to isolated case reports or small case series [6,10,25,26,27,28] . In contrast to previous reports, we found that fv-D was often larger in patients with uterine AVMs than in those without uterine AVMs, and this was true for AVMs occurring in both the myometrium and the parametrium (P < 0.001) in our study.…”

“…This may be associated with large amounts of blood drained through the parametrium vessels, and we speculate that fv-D may be proportional to the shunt volume of uterine AVMs (i.e., a greater volume of shunted blood is associated with a larger diameter). Although the erosive nature of the syncytiotrophoblastic tissue and chorionic villi can increase angiogenesis in the myometrium [30,36] , this phenomenon does not necessarily indicate the formation of an AVM. On the other hand, the dilation of ow voids in the myometrium may be limited by the resistance of the myometrium.…”