Atypical macroglossia caused by multiple myeloma‐associated systemic amyloidosis with severe lingual movement disorder and tongue sclerosis

A 70‐year‐old man presented with dysphagia and difficulty in moving the tongue. Macroscopic findings showed features resembling mild tongue atrophy. We suspected a neurodegenerative disease which causes tongue atrophy such as amyotrophic lateral sclerosis. A needle electromyogram showed a strong resistance from the tongue owing to its hardness. Detection of Bence Jones protein κ type M protein in the serum led to a diagnosis of multiple myeloma‐associated light‐chain (κ) type amyloidosis. Thus, in patients with a rugose‐textured and uneven tongue mimicking atrophy, macroglossia caused by amyloidosis should be considered by examining the tongue hardness.