Retained products of conception with uterine arteriovenous malformation: A case report

Rationale: Uterine arteriovenous malformation (UAVM) is a rare but potentially life-threatening cause of abnormal uterine bleeding. Diagnosis is particularly challenging when UAVM coexists with retained products of conception (rPOC), as both entities can present with overlapping clinical and imaging features. Accurate differentiation is essential for appropriate management, especially in women desiring preservation of fertility. Patient concerns: A woman of reproductive age presented with recurrent episodes of profuse vaginal bleeding, accompanied by progressive anemia. The severity, persistence, and recurrent nature of the hemorrhage raised strong suspicion of an underlying uterine vascular pathology, necessitating urgent diagnostic evaluation and prompt intervention. Diagnoses: Color Doppler ultrasonography and pelvic magnetic resonance imaging demonstrated a markedly hypervascular intrauterine lesion, which led to an initial presumptive diagnosis of uterine arteriovenous malformation. In the context of life-threatening hemorrhage, an acquired UAVM was considered the most likely diagnosis. However, due to substantial overlap in clinical presentation and imaging features, definitive preoperative differentiation from retained products of conception remained challenging. Interventions: Emergency uterine artery embolization was performed as a first-line, fertility-preserving therapeutic approach. Digital subtraction angiography, the diagnostic gold standard for UAVM, revealed extensive collateral vascular networks supplying the lesion, resulting in incomplete devascularization and subsequent embolization failure. Given the persistence of active bleeding and a rapid decline in hemoglobin levels, uterine-sparing surgical excision of the lesion was subsequently undertaken to achieve definitive hemostasis. Outcomes: The surgical procedure successfully controlled the hemorrhage without the need for hysterectomy. Histopathological analysis of the resected specimen demonstrated retained chorionic villi coexisting with an acquired uterine arteriovenous malformation, thereby establishing a retrospective diagnosis of rPOC-associated UAVM. The patient had an uneventful postoperative course and remained free of recurrent vaginal bleeding during follow-up. Lessons: This case illustrates the diagnostic difficulties posed by the coexistence of UAVM and rPOC, particularly due to their shared hypervascular imaging characteristics. Persistent collateral perfusion may limit the effectiveness of uterine artery embolization in such mixed lesions. Uterine-sparing surgery can provide both definitive hemostasis and histopathological confirmation when embolization fails. Early recognition of rPOC-associated UAVM is crucial for guiding individualized management and for preserving reproductive potential in affected women.