Interpreting segmental glomerular sclerosis

Abstract

The term ‘focal segmental glomerulosclerosis’ (FSGS) is used to describe the common morphologic lesion underlying various progressive renal diseases and also to describe the clinical syndrome with occurrence of the primary idiopathic lesion of focal segmental glomerulosclerosis. Different morphological patterns of focal segmental glomerulosclerosis are associated with different processes, reflecting the presence of diverse pathogenic mechanisms leading to focal sclerosis. The diagnosis of FSGS rests first on the recognition of segmentally sclerotic glomeruli, and then on specific morphologic features to distinguish the various types of FSGS. Five main light microscopic patterns of FSGS have been defined by the Columbia Consensus Classification of FSGS. Some of these patterns may be also observed in some secondary forms of FSGS. The location of sclerosis and the recognition of particular light microscopic patterns, immunofluorescence and electron microscopy findings can provide important information about the aetiology and prognosis of the lesion.