Nephrotic syndrome with mesangial-cell proliferation in children--a distinct entity?

Various morphologic patterns have been identified in renal biopsies of children with the idiopathic nephrotic syndrome. Children with focal segmental glomerulosclerosis have clinicopathologic features sufficiently distinct to warrant a separate subclassification. "Immunoglobulin M (IgM) nephropathy" and other morphologic patterns are less well defined. The clinicopathologic characteristics of eight patients with the nephrotic syndrome, increased mesangial cellularity on renal biopsy, and hematuria (mesangioproliferative nephropathy) were evaluated. Response to standardized prednisone therapy was poor. Of the seven children followed for 7-29 months, only two were in remission at the time of writing, and each of these had had one prior relapse. The eighth patient was lost to follow-up after one month. Although the number of patients studied was small, there was a strong correlation between degree of mesangial-cell proliferation and failure of primary treatment. As concepts of the pathogenesis of idiopathic nephrotic syndrome in children continue to evolve, the mesangioproliferative lesion should be recognized and marked for further study.