A Rare Case of Diffuse Pulmonary Arteriovenous Malformations Secondary to Placental Site Trophoblastic Tumor

Introduction: Placental site trophoblastic tumors (PSTT) is a rare neoplasm arising from trophoblast cells. Pulmonary arteriovenous malformations (PAVMs) secondary to PSTT is an exceedingly rare complication. We hereby present a case of multiple PAVMs in the setting of metastatic PSTT. Case Presentation: A 34-year-old lady initially presented with abnormal uterine bleeding, high output cardiac failure and was found to have an elevated serum beta-hCG levels, a uterine mass on pelvic ultrasound, a pelvic AVM and multiple uterine AVMs. She underwent hysterectomy and bilateral salpingo-oophorectomy which confirmed the diagnosis of PSTT with evidence of uterine AVMs. She received etoposide, methotrexate, actinomycin, and cisplatin with favorable response but was later found to have pulmonary cystic metastases. She was treated with immunotherapy and additional chemotherapy, but failed to respond and subsequently developed embolic stroke leading to seizures. Her course was further complicated by secondary spontaneous pneumothorax requiring chest tube placement. Two years later, she was admitted with acute hypoxemic respiratory failure and underwent chest CT with contrast that revealed progression of the cystic pulmonary metastases in addition to innumerable new PAVMs (image 1). The largest 2 PAVMs were treated with embolization with Amplatz II vascular plugs with improvement in her symptoms. She was ultimately admitted with COVID-19 pneumonia and subsequently developed refractory shock with evidence of diffuse multiple air emboli (image 1) on CT imaging. Despite aggressive resuscitation, the patient ultimately passed away. Discussion: PAVMs are abnormal vascular communications between pulmonary arterial and venous circulation without a normal intervening capillary network. The vast majority of PAVMs occur in the setting of hereditary hemorrhagic telangiectasia. The direct communication between the pulmonary arteries and veins without the filtering capillary bed increases the risk paradoxical embolization of thrombi and bacteria leading to stroke and brain abscess. While AVMs are seen in the uterus in cases of PSTT, PAVMs are considered an exceedingly rare complication with very few cases reported in the literature. The development of AVMs in PSTT is thought to be secondary to proangiogenic effects of hCG in addition to the expression of vascular endothelial growth factor (VEGF) by tumor cells. We hypothesize that the patient developed air embolism secondary to a ruptured cystic metastatic lesion into an adjacent PAVM leading to death. Clinicians need to be aware of the risk of developing PAVMs in patients with PSTT and the potential serious complications associated with them including refractory hypoxemia and paradoxical embolism.