[Intracytoplasmic crystals and Fanconi syndrome in a patient with IgA kappa myeloma]. / Cristales intracitoplasmáticos y síndrome de Fanconi en un paciente con mieloma IgA kappa.

A 45 year old man with IgA-Kappa myeloma had adult Fanconi Syndrome. Examination of renal biopsy revealed lesions in proximal tubules without glomerular lesions and without intratubular casts. By electron microscopy cytoplasmic crystalline inclusions were observed in renal proximal tubular epithelium. Increased plasma cells (28%) in bone marrow aspiration also contained crystalline inclusions. The treatment of myeloma produced partial remission of proliferative disease and Fanconi syndrome. We discuss the pathogenesis of Fanconi syndrome induced by light chains as well as the composition of crystalline deposits and the effects of treatment on Fanconi Syndrome.