Case Report: Challenges in the diagnosis and treatment of cardiac amyloidosis: a case misdiagnosed as dual cardiac amyloidosis

Cardiac amyloidosis (CA) is a pathologic condition characterized by the cardiac deposition of insoluble misfolded proteins, often resulting in nonspecific symptoms that complicate diagnosis. Although advances in diagnostic techniques have improved the diagnostic rates, accurate identification of amyloid fibril deposits remains challenging. Here, we present a 52-year-old Chinese woman who was initially diagnosed with both wild-type cardiac transthyretin amyloidosis (ATTR-CA) and lambda cardiac light-chain amyloidosis (AL-CA) after the standardized diagnostic workup. Subsequent liquid chromatography-tandem mass spectrometry, however, identified lambda light chains as the primary amyloidogenic protein, confirming a final diagnosis of lambda AL-CA. The diagnostic process was further complicated when a review of ^99mTc-pyrophosphate scintigraphy turned strongly positive after an eleven-month interval. Following the patient's refusal of chemotherapy, her heart failure progressively worsened, requiring the support of vasoactive and inotropic drugs, and she ultimately succumbed to cardiogenic shock 17 months after initial presentation. This case underscores the diagnostic challenges and necessity of sophisticated techniques for accurately typing CA.