[Improvement of chylothorax after lymphangiography in AL amyloidosis].

A 74-year-old man presented with leg edema and was found to have nephrotic-range proteinuria. Renal biopsy revealed AL amyloidosis. Subsequent bone marrow examination demonstrated an increase in monoclonal plasma cells accounting for 13% of nucleated cells. Right-sided pleural effusion developed and was confirmed to be chylothorax. Although treatment with daratumumab, lenalidomide, and dexamethasone (DLd regimen) was initiated, the pleural effusion continued to increase. Lymphangiography using ethiodized oil identified a leakage point in the anterior mediastinum. A chest drain was inserted on the following day, and approximately 4 l of chylous fluid was drained. The tube was removed one week later, and pleural effusion did not recur thereafter. Although a hematologic response was achieved, the nephrotic syndrome persisted, and the patient ultimately died. Chylothorax associated with AL amyloidosis is rare and difficult to treat. This case suggests that lymphangiography using ethiodized oil may be both diagnostic and therapeutic.