Massive splenic mixed vascular malformation with synchronous retroperitoneal and gluteal malformations in pregnancy: a case report and literature review

Abstract Background Splenic vascular anomalies are rare clinical entities, and their occurrence during pregnancy presents a complex therapeutic dilemma. The physiological hemodynamic changes associated with gestation significantly elevate the risk of rapid expansion and spontaneous rupture, posing a catastrophic threat to both maternal and fetal survival. Reports of giant mixed vascular malformations of the spleen coexisting with systemic extra-splenic vascular anomalies in pregnancy remain exceedingly rare. Case presentation We report a case of a 25-year-old primigravida who presented at 16 + 6 weeks of gestation with a rapidly enlarging abdominal mass. Magnetic Resonance Imaging (MRI) revealed a giant cystic-solid lesion replacing the spleen (31 × 21 × 17 cm) and identified concurrent multiple vascular malformations in the retroperitoneum and gluteal regions. A preoperative percutaneous biopsy was omitted due to the high risk of spontaneous hemorrhage, and the lesion was presumed benign based on MRI characteristics. Due to the imminent risk of rupture and mechanical compression, a multidisciplinary team (MDT) recommended surgical intervention. The patient underwent an elective open total splenectomy, and the extra-splenic lesions were managed conservatively. Histopathological examination confirmed a mixed venolymphatic malformation according to ISSVA terminology. The postoperative course was uneventful. The pregnancy continued to term, resulting in the successful cesarean delivery of a healthy neonate at 39 + 2 weeks. Conclusion This case highlights the critical role of MRI in the precise anatomical mapping of complex vascular lesions and underscores the necessity of an MDT approach in managing high-risk surgical pathologies during pregnancy. The second trimester represents the optimal therapeutic window for intervention. For giant splenic lesions where minimally invasive techniques are unfeasible, open splenectomy represents a safe strategy to ensure maternal safety and fetal viability.