[A case of collapsing variant of FSGS]

We report a case of collapsing variant of FSGS. An 82-year-old man without HIV-1 infection or a history of intravenous drug abuse was admitted to our hospital with the chief complaints of acute onset of generalized edema and loss of appetite. Laboratory findings were consistent with nephrotic syndrome. He developed acute renal insufficiency. Initially, we suspected minimal change nephrotic syndrome and started steroid pulse therapy but the nephrotic syndrome was refractory and a renal biopsy was performed. The pathologic findings were judged to be consistent with a collapsing variant of focal segmental glomerulosclerosis (FSGS). This form was described by Weiss et al. in 1986 as a clinically and pathologically distinct variant of FSGS. Valeri et al. further reported that the incidence of this idiopathic collapsing type of FSGS which is devoid of evidence of HIV-1 infection or intravenous drug abuse has progressively increased over the past two decades. They reported that cyclosporin is effective for the treatment of this type of FSGS with a remission rate of about 30%. The present case also had a nearly complete remission after 2 month-cyclosporin treatment. In Japan, no adult case of this type of FSGS has been reported according to our review of the literature.