Overdiagnosis: under-recognized clinical and pathological features of "focal ischemic glomerulosclerosis clustering".

"Focal ischemic glomerulosclerosis clustering (FIGSC)" is a term used by us temporarily to describe a rare kind of focal renal scar with a high percentage of global sclerosis in the renal biopsy tissue. We retrospectively studied the clinical and pathological data from 15 cases of FIGSC followed up in order to avoid overdiagnosis and to investigate its diagnostic basis. We found that in 7 cases with FIGSC, the percentage of global sclerosis was higher than 50% with mild or moderate tubulointerstitial lesions, and most cases showed sclerotic regions distributed both beneath the renal capsule and in the deep cortex. Fourteen cases of afferent arterioles sclerosis were observed. Fourteen did not evolve to end-stage renal disease (ESRD) during the follow-up period. The values of the percentage of severe tubulointerstitial lesion, SCr, BUN, and the cumulative incidence of ESRD were significantly lower compared to the diffuse proliferative sclerosis glomerulonephritis group (P<0.05). The results suggest that the essence of FIGSC may be a kind of focal renal scar related to sclerosis, stenosis or obstruction of several adjacent afferent arterioles, not caused by original glomerulonephritis. Comprehensive understanding should be very important to avoid overdiagnosis and overtreatment.