Secondary amyloidosis associated with histiocytosis X.

We report a 34-year-old man diagnosed with Langerhans cell histiocytosis (LCH) or histiocytosis X in 1980. He had multiple focal osseous lesions, difficult control of the disease activity and was treated many times with chemo- and radiotherapy for symptomatic control. His kidney disease started 20 years after the diagnosis with progressive renal failure and increasing non-nephrotic proteinuria, coinciding with two flares of LCH. A percutaneous renal biopsy demonstrated amyloidosis. There is only one case described in the amyloidosis literature associated with LCH.