Metastatic Signet Ring Cell Carcinoma Masquerading as Acute on Chronic Thromboembolic Pulmonary Hypertension Requiring ECMO

Introduction Pulmonary thromboembolism can result from underlying hypercoagulability. Malignancy can cause hypercoagulability; however, gastrointestinal malignancy is rare in pediatric patients. We present the case of an adolescent female with severe pulmonary thromboemboli and subsequent right heart failure requiring venoarterial extracorporeal membrane oxygenation (VA ECMO) who was found on autopsy to have widely metastatic signet ring cell carcinoma (SRCC) of gastric origin. Case Report An obese 16-year-old female taking combination oral contraceptives for menorrhagia presented to an outside facility with chest pain, dyspnea, and vomiting. She had no recent history of travel, surgery, or trauma. Her father had been diagnosed with protein C/S deficiency, though she had tested negative for this. She had inverted T-waves with elevated troponin. Chest computed tomography angiogram revealed bilateral pulmonary arterial thrombi and evidence of right heart strain. After transfer to our institution, she developed cardiogenic shock from right ventricular failure. She was placed on peripheral VA ECMO. After failing to wean from ECMO, she was evaluated by our lung transplant committee but was declined for listing. She continued to deteriorate despite ECMO support and maximal medical therapy, developing refractory sepsis and coagulopathy. After one month on ECMO, decannulation was performed. She expired two days later due to multi-system organ failure. Autopsy revealed widely metastatic diffuse SRCC of gastric origin that was not seen on multiple rounds of axial imaging and endoscopies (Figure 1). Summary This report highlights an unusual cause of pediatric hypercoagulability resulting in pulmonary embolism and right heart failure requiring mechanical circulatory support. It is imperative to maintain a broad differential diagnosis for pediatric patients requiring mechanical circulatory support.