A Focus on Waldenström Macroglobulinemia and AL Amyloidosis

Abstract

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma that is characterized by the overproduction of an IgM monoclonal protein. It may cause adenopathy, hepatomegaly, splenomegaly, as well as other disease-related complications such as cold agglutinin anemia, cryoglobulinemia, hyperviscosity, and neuropathy. While light chain amyloidosis in patients with WM only occurs in about 10% of patients, it is important that advanced practitioners are able to recognize concurrent AL amyloidosis, which will affect the patient's treatment trajectory. Diagnosis of WM with AL amyloidosis is based on bone marrow biopsy and a fat pad biopsy. If AL amyloidosis is suspected, the bone marrow and fat pad biopsy should undergo Congo red staining. If it is negative, and there is a strong suspicion of AL amyloidosis, then an organ biopsy can be considered. Treatment of WM uses rituximab-based therapy in combination with a variety of other agents, including proteasome inhibitors, alkylating agents, and BTK inhibitors. Treatment of light chain amyloidosis uses bortezomib as the backbone of therapy and can be administered with cyclophosphamide, dexamethasone, and now daratumumab, which was recently approved. Waldenström macroglobulinemia and light chain amyloidosis are both rare diseases and can lead to a variety of disease-related complications. Fortunately, many options exist for both diseases. This article will highlight a case of WM with amyloidosis and a case of a patient with relapsing WM with considerations for advanced practitioners managing this patient population.

Figure 1

(A) H & E section showing eosinophilic amorphous materials in the wall of a vessel and some in the interstitium of a bone marrow trephine biopsy. (B) Congo red stains the vessel. (C) Apple green birefringent materials in the Congo red–stained soft tissue viewed under polarized light.