Abstract
Subinvolution of the implantation site is a significant contributor to delayed postpartum hemorrhage (PPH). There is immense literature documenting the histologic features, development, and involution of the uteroplacental site; however, practice-oriented literature on subinvolution of the implantation site is sparse. In the present study, we briefly review the physiologic characteristics associated with the normal development and involution of uteroplacental arteries and the proposed pathophysiologic attributes of subinvolution. Furthermore, we engage in a comparison of the condition with preeclampsia. Herein, we report a case of postpartum vaginal bleeding that persisted for two weeks following cesarean delivery. The bleeding was nonresponsive to conservative treatment. Sonography performed revealed that a heterogeneous intrauterine vascular mass measuring 14.6 × 9.2 × 10.4 cm was present, distending the uterine cavity. The presence of retained products of conception could not be ruled out. Therefore, to further confirm the condition, the patient underwent an emergency hysterectomy. Gross examination showed an enlarged and boggy uterus with numerous dilated and ecstatic thrombosed blood vessels in the implantation site of the endomyometrium. Histologic and immunohistochemical examination of the implantation site revealed the presence of persistently patent uteroplacental arteries with variable degrees of thrombosis adjacent to normally involuted vessels. Hence, a diagnosis of placental site vessel subinvolution (VSI) was established in this case. We also reviewed the related literature to illustrate the informative histologic findings of subinvolution. Preparing the ground for diagnosing subinvolution is important as this process defines that the cause of delayed postpartum uterine bleeding is idiopathic, rather than iatrogenic.
Highlights
Postpartum hemorrhage (PPH) is a major cause of maternal deaths worldwide due to its association with hemorrhagic shock and the tendency to develop disseminated intravascular coagulation [1,2]
We provide a description of a rare type of recurrent secondary PPH caused by local vessel subinvolution (VSI) after an uncomplicated cesarean delivery and present a review of the available literature to support our findings [6,10]
The findings further showed the formation of venous varix and the indication of the subinvolution of the placental site
Summary
Postpartum hemorrhage (PPH) is a major cause of maternal deaths worldwide due to its association with hemorrhagic shock and the tendency to develop disseminated intravascular coagulation [1,2]. The findings further showed the formation of venous varix and the indication of the subinvolution of the placental site Despite these results, the presence of retained products of conception could not be ruled out. Microscopic examination of the myometrium beneath the placental implantation site revealed the presence of persistently patent uteroplacental arteries adjacent to normally involuted vessels (Figure 1). 5A: subinvoluted blood vessel showing persistent EVT replacing normal endothelium; CD34 negative in the subinvoluted vessel wall; CD34 positive in the adjacent myometrial vessels (internal positive control) (x20). 5B: subinvoluted blood vessel showing numerous persistent PAN-CK-positive endovascular trophoblastic cells; PAN-CK-positive endometrial glands (internal positive control) (x20). 5C: subinvoluted blood vessel showing numerous persistent P63-positive EVT in the vessel wall (x20). 5D: subinvoluted blood vessel showing numerous persistent P63-positive EVT in the vessel wall and surrounding interstitium (x20). She recovered fully and was found to be asymptomatic on follow-up
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