[Light chain deposition disease. Experience in our environment]

The Light chain deposition disease (LCDD) is a strange entity characterised by the deposition of only one type of light chain in the renal tubular basement membranes. It can be associated to a plasma cell dyscrasia, however, it can occur in the absence of any detectable hematological disorder and it is called idiopathic LCDD. The clinical manifestation is renal insufficiency and nephrotic proteinuria, it does not have a clearly fixed treatment and has a severe prognosis. The aim of this work is to analyse the characteristics of the LCDD cases diagnosed within our environment. Six cases were identified, all of them between 1999 and 2005, from a total amount of 640 renal biopsies performed during this period, 4 women and 2 men, average age of 57. Multiple myeloma in 3 patients were detected (50%). The acute renal failure or rapidly progressive renal insufficiency was the most frequent clinical presentation (66%) together with nephrotic proteinuria (66%). All the biopsies showed tubular basement membranes thickening and kappa chains with a linear distribution within the same. The most frequent glomerular pathological finding was the nodular sclerosing glomerulopathy (83%). In one of the cases the affectation was exclusively tubular interstitial with tubular casts. 3 patients were treated, 2 with multiple myeloma. 5 patients needed dialysis: 3 with idiopathic LCDD within an average time of 7 days from the diagnosis to its reception and 2 with myeloma, who started needing dialysis in an average of 46 days. 4 patients died, 2 of them with myeloma. The monitoring time until the death was 13 weeks for the patients with myeloma and 110 weeks for the rest.

The LCDD seems to be more frequent than what has been published and it is associated to the myeloma in half of the cases. It appears together with severe renal insufficiency and the patient's and renal prognosis is poor.