Clinicopathologic study of glomerulonephritis showing double-contour lesions

Background To elucidate the pathologic significance of double-contour lesions of glomerular capillary walls, we determined how the clinical course of patients with diffuse and global double-contour lesions differs from that of patients with segmentally located double-contour lesions. Methods In 26 out of 308 cases of idiopathic glomerulonephritis double contour lesions and serum complement 3 (C3) deposition along capillary walls were histologically examined. Results Most patients with diffuse (affecting more than 80% of all glomeruli) and global (affecting more than 75% of each glomerulus) double-contour lesions exhibited a persistent profound proteinuria and a deterioration of renal function (assessed via serum creatinine measurements) during a mean observation period of 66 months, even when a transient remission was observed. The amelioration of hypocomplementemia correlated significantly with an improvement in proteinuria (P<0.05). A follow-up biopsy of patients revealed some cases in which there was: (1) no amelioration of the glomerular lesion despite improvements in renal function, proteinuria and hypocomplementemia; (2) an amelioration of the glomerular lesion paralleling an increasing stability in renal function and a reduction in proteinuria; or (3) deterioration of the glomerular lesion paralleling a decrease in renal function, an increase in proteinuria, and persistent hypocomplementemia. Conclusions These findings indicate that the clinical characteristics of mesangiocapillary glomerulonephritis differ from those of other types of mesangial proliferative glomerulonephritis with segmentally-located double-contour lesions. A spot, unrepeated biopsy in cases of atypical mild mesangiocapillary lesions provides insufficient information to reach a diagnosis of mesangiocapillary glomerulonephritis.