A 61-year-old man presented to the hematology department with progressive difficulty in swallowing food. He also described a 2-year history of edema in his hands and face as well as dry skin and hair loss. Physical examination of the oropharynx showed macroglossia with posterior scalloping, erythema of the palatoglossal arch, and an enlarged uvula. Biopsy of the uvula was performed, and staining with Congo red showed apple-green birefringence suggestive of amyloid deposits. Immunohistochemical analysis showed high circulating levels of kappa light chain. Serum electrophoresis with immunofixation revealed a monoclonal spike of 0.4 g per deciliter. Additional evaluation was notable for a level of free kappa light chain of 56.6 mg per liter (reference range, 8.3 to 27.0), an elevated ratio of kappa to lambda light chains of 3.3 (reference range, 0.26 to 1.65), and proteinuria (0.26 g of protein in a 24-hour urine sample). Flow cytometry of bone marrow showed 0.54% plasma cells with an atypical phenotype, and cardiac magnetic resonance imaging was suggestive of amyloid involvement in the left ventricular myocardium. Amyloidosis is characterized by deposition of abnormal proteins in extracellular tissue; in the light-chain form of the disease, the extracellular tissue is derived from immunoglobulin light chains associated with a plasma-cell dyscrasia. The patient underwent autologous bone marrow transplantation and had a complete response.