Abstract
Brain natriuretic peptide (BNP) is a well-established biomarker for heart failure (HF). However, its diagnostic utility can be limited in patients with comorbidities that independently elevate serum BNP levels, including chronic renal failure and sepsis. We describe a rare occurrence of significantly elevated serum BNP levels in a patient with metastatic urothelial cancer without HF or obvious signs of sepsis. The report highlights the need for considering alternative causes for increased serum BNP levels, especially in the presence of malignancy.