Senile transthyretin cardiac amyloidosis in patients with plasma cell dyscrasias: importance of cardiac biopsy for making the correct diagnosis.

Amyloidosis refers to a group of widely diverse conditions characterized by the deposition of insoluble protein within the extracellular space, leading to disruption of normal organ function. AL primary amyloidosis is associated with plasma cell dyscrasias and is caused by the deposition of insoluble kappa or lambda light chains. Cardiac involvement by AL primary amyloidosis has a very poor prognosis, and patients are treated with systemic chemotherapy. Clinically, the presence of cardiac amyloidosis in patients with plasma cell disorders is usually presumed to represent AL primary amyloidosis, and they are often managed as such. We reported four cases of elderly patients with plasma cell disorders who were found to have biopsy-proven cardiac senile transthyretin amyloidosis. Our cases demonstrated that cardiac amyloidosis in patients with plasma cell disorders does not necessarily represent AL primary amyloidosis. Cardiac biopsy is important in making the correct diagnosis. Accurate subtyping of the amyloid has significant implications in the management of patients and discussion of prognosis.