A lost race against time-a rare case of AL amyloidosis.

introductionAmyloidosis is a rare multi-system disease that can affect the heart. Recent advances have been made in finding successful treatments for these patients. Nonetheless, cardiac amyloidosis continues to carry high morbidity and mortality. CASE PRESENTATION: This case refers to a 52-year-old man presenting with signs and symptoms of heart failure. Electrocardiogram showed q waves in V1-V3 and T wave inversion in the inferior and lateral leads. Echocardiography revealed moderate concentric left ventricular hypertrophy, with preserved biventricular systolic function and no other changes. Cardiac magnetic resonance showed severe left ventricular hypertrophy and diffuse fibrosis, suggesting infiltrative cardiomyopathy. Given these findings, a diagnosis of amyloidosis was considered and complementary tests were requested. Laboratory tests showed elevation of Kappa light chains in urine, with normal serum light chains. Cardiac scintigraphy with Tec99m-DPD showed increased cardiac uptake. Genetic testing showed no clinically relevant variants in the TTR gene. Salivary gland and abdominal fat biopsy demonstrated no deposition of amyloid substance. Bone marrow evaluation demonstrated the presence of 0.8% plasma cells (99.2% clonal). Given that a high degree of suspicion remained, an endocardial biopsy was performed and immunohistochemical staining revealed deposits of kappa light chains, suggesting AL amyloidosis. However, in the course of the clinical investigation, the patient's condition progressively deteriorated. By the time AL amyloidosis was diagnosed and targeted therapy initiated, the patient was already severely debilitated, ultimately leading to a short-term fatal outcome. COMMENT: Amyloidosis, often undiagnosed early, can severely affect multiple organs, particularly the heart, leading to poor prognosis without timely intervention. In this case, AL amyloidosis, a type where plasma cells produce amyloidogenic light chains, was identified. The patient's late diagnosis led to rapid progression and treatment with chemotherapy and steroids; however, his condition deteriorated quickly, resulting in a fatal outcome.