Amyloid myopathy is a rare manifestation of amyloid light chain amyloidosis. We present a case of a 41-year old male with multiple myeloma with muscle hypertrophy, muscle weakness and enlargement of the submandibular glands as the only presenting clinical symptoms, illustrating the sheer difficulty of diagnosing amyloid light chain amyloidosis in patients with mainly soft tissue involvement. Even if there is a clinical suspicion, it is often hard to verify as Congo red stain and immunohistochemistry on muscle biopsy are not always reliable. After bortezomib-based induction treatment followed by autologous stem cell transplantation with high dose melphalan conditioning, he achieved complete haematological remission as well as a significant clinical response. We would like to highlight the importance of early diagnosis and treatment, as progression to more extensive visceral involvement can lead to rapid occurrence of organ failure and death.

(BELG J HEMATOL 2017;8(3):113–7)