Rinsho Shinkeigaku (Clinical Neurology)

Brief Clinical Note

A case of systemic AL amyloidosis diagnosed on muscle biopsy

Tomohiro Yata, M.D.1)2), Takashi Miwa, M.D.1)3), Katsuya Araki, M.D., Ph.D.1), Toru Kida, M.D.4), Keiko Toyooka, M.D., Ph.D.2), Ichizo Nishino, M.D., Ph.D.5) and Chikao Tatsumi, M.D., Ph.D.1)

1)Department of Neurology, Toyonaka Municipal Hospital
2)Department of Neurology, Osaka Toneyama Medical Center
3)Department of Neurology, Osaka University Graduate School of Medicine
4)Department of Internal Medicine (Hematology), Toyonaka Municipal Hospital
5)Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP)

A 69-year-old man was admitted to our hospital with a 1-year history of progressive easy fatigability while walking. He presented with proximal muscle weakness dominant in the lower extremities, hoarseness, and mild dysphagia. Muscle pseudo-hypertrophy was observed in the gastrocnemius. A biopsy specimen from the left deltoid muscle revealed amyloid deposition in the blood vessels and ring-like fibers. These findings suggested amyloid myopathy. The serum and urine immunofixation electrophoresis detected κ type Bence-Jones proteins, and bone marrow examination showed an increase in atypical plasma cells; thus, we established a diagnosis of multiple myeloma. Thereafter, he experienced frequent diarrhea, and the gastrointestinal endoscopy revealed extensive amyloid deposition in the upper and lower digestive tract. We started treatment with lenalidomide and dexamethasone; however, his condition worsened, and he died of aspiration pneumonia. Amyloid myopathy indicated systemic AL amyloidosis; therefore, muscle biopsy was necessary in this case.
Full Text of this Article in Japanese PDF (2135K)

(CLINICA NEUROL, 60: 60－63, 2020)
key words: amyloid myopathy, AL amyloidosis, multiple myeloma, muscle biopsy

(Received: 27-Jun-19)