Amyloid-associated muscle pseudohypertrophy and multiple myeloma in a man with hypernephroma.

Amyloidosis is known to occur both in renal adenocarcinoma and multiple myeloma. This paper describes a 52-year-old man who developed multiple myeloma and widespread amyloidosis after surgical removal of a hypernephroma. Multiple myeloma presented with osteolytic bone lesions and slight bone marrow plasmocytosis. Both kappa light chains and monoclonal IgG were secreted. Amyloidosis was seen as muscle pseudohypertrophy with wood-hard masses of amyloid in shoulders, girdle, buttocks and proximal limbs. Macroglossia was impressive and swelling of submandibular structures and the floor of the mouth was marked. Knowing the peculiar immunological potency of hypernephroma, attention is called to associations between renal carcinoma and monoclonal gammopathies, including amyloidosis.