Unicentric Castleman's disease associated with malignant cardiac Amyloid-A amyloidosis: a case report.

Background: Unicentric Castleman's disease (UCD), a lymphoproliferative disorder characterized by enlargement of the lymph nodes, is a rare cause of Amyloid-A amyloidosis. While patients usually present with impaired kidney function and proteinuria, heart involvement is neither common nor the main cause of signs and symptoms. Case summary: We present a patient who was admitted to the hospital for impaired exercise capacity. Diagnostic work-up revealed severe left ventricular hypertrophy suggestive of cardiac amyloidosis. Although Congo red staining of endomyocardial biopsies was initially negative, subsequent immunohistochemical staining against serum amyloid A finally confirmed the diagnosis of cardiac amyloidosis. 18F-fluorodeoxyglucose positron emission tomography/computed tomography revealed a tumour located in dorsal of the duodenum. Fine-needle aspiration biopsy of the tumour was suggestive but could not confirm the presence of UCD beyond reasonable doubt. Rapid worsening of heart failure symptoms warranted urgent surgical tumourectomy, which resulted in immediate post-operative lowering of serum amyloid protein. However, post-operative cardiogenic shock could not be stabilized even with veno-arterial extracorporeal membrane oxygenation, and the patient eventually died. The UCD of the hyaline vascular (HV) subtype was confirmed by pathologic work-up of the excised tumour. Discussion: This case report presents for the first time a patient with malignant cardiac Amyloid-A amyloidosis caused by unicentric Castleman's disease of the HV subtype. Since the disease progresses swiftly, rapid diagnosis is essential for potential curative treatment.