Muscle involvement with pseudohypertrophy in systemic light chain amyloidosis: Case report

Abstract

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 λAL 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.