Muscle involvement with pseudohypertrophy in systemic light chain amyloidosis Case report

Rationale: Muscle pseudohypertrophy is a rare manifestation of light chain amyloidosis (AL) amyloidosis. Patient concerns: A 63-year-old woman presented with a 2-year history of progressive asthenia, macroglossia, dysphonia, cachexia, hypotension, paresthesia, and lower limb muscle hypertrophy. Diagnosis: Free serum lambda light chains were increased, and fat pad biopsy demonstrated Congo red-positive deposits. Additionally, electromyography showed a myopathic pattern, whereas muscle biopsy revealed amyloid deposits. A diagnosis of lambda AL with cardiac, renal, nervous system, and skeletal muscle involvement was established. Interventions and outcomes: The patient received 3 subsequent lines of therapy over the following 23 months, with very slow hematological remission followed by resolution of organ dysfunction. Lessons: Despite its rarity, muscle involvement should be considered in patients diagnosed with AL amyloidosis associated with unexplained muscle hypertrophy or weakness associated with macroglossia or elevated troponin T levels in the absence of clear cardiac involvement.

Automated summary

This case report highlights a rare manifestation of light chain amyloidosis (AL) amyloidosis, presenting as muscle pseudohypertrophy with involvement of the heart, kidneys, nervous system, and skeletal muscles. The patient received three subsequent lines of therapy over 23 months, resulting in slow hematological remission and resolution of organ dysfunction.