Discussion
WM is a non-Hodgkin lymphoma characterized by the invasion of lymphoplasma cells into bone marrow and IgM-monoclonal proteinemia. The incidence rate of WM is 3–4 cases per million persons per year, accounting for only 1% of lymphomas1. WM causes AL amyloidosis in only 3% of WM cases2. Information about cutaneous manifestations of WM-related AL amyloidosis is limited.
AL amyloidosis affects various organs/tissues including the kidneys, heart, nerves, and skin3. Cutaneous manifestations are dependent on the histological area where amyloid protein deposits; previous literature reported that protein deposition in vessel walls, folliculosebaceous units, and the epidermis/dermis causes purpura, alopecia, and papules/nodules, respectively4. Purpura is reportedly caused by vessel fragility due to the deposition and abnormality of the coagulation/fibrinolysis system5. Our case, however, presented with papules/nodules and not purpura. The cutaneous manifestation was considered to have developed by the following mechanisms: i) abnormalities of factors controlling coagulation and fibrinolysis were not severe enough to cause the collapse of the coagulation/fibrinolysis system; ii) the vascular endothelial cells were not destroyed by the deposition, compatible with the histopathological findings that vascular endothelial cells were not affected by the deposition; and iii) marked deposition around vessels in the dermis and subcutis caused papules/nodules.
This case report provides evidence that WM may cause cutaneous manifestations represented as papules/nodules through the development of AL amyloidosis.
Acknowledgement: None
Statement of Ethics: This study protocol was approved by The Ethics Committee of The Jikei University School of Medicine and the patient provided written informed consent.