A Rare Presentation of Metastatic Extragonadal Nonseminomatous Germ Cell Tumor Complicated by Suspected Transfusion-Associated Circulatory Overload.

Extragonadal nonseminomatous germ cell tumors (NSGCTs) are rare and aggressive malignancies that commonly present with advanced metastatic disease and elevated tumor markers. We present the case of a 27-year-old man with no significant past medical history who presented with abdominal pain, dark stools, fatigue, weight loss, and severe normocytic anemia. Imaging revealed a large retroperitoneal mass with extensive pulmonary and hepatic metastases, while tumor marker evaluation demonstrated markedly elevated beta-human chorionic gonadotropin levels without evidence of a primary testicular lesion, consistent with metastatic extragonadal NSGCT. The patient required multiple packed red blood cell (pRBC) transfusions for progressive anemia, and subsequently developed acute hypoxic respiratory failure with pulmonary edema concerning for transfusion-associated circulatory overload (TACO). Despite intensive care management, embolization for active hepatic bleeding, and initiation of chemotherapy, the patient experienced progressive clinical deterioration and expired following cardiac arrest. This case highlights the aggressive clinical course of metastatic extragonadal NSGCT and the challenges associated with transfusion-related pulmonary complications in critically ill oncology patients. It also emphasizes the importance of careful transfusion practices, clinical vigilance, and early recognition of transfusion reactions in patients with significant inflammatory burden, ongoing hemorrhage, and extensive metastatic disease.