Which condition typically shows a "lumpy-bumpy" appearance of glomeruli on immunofluorescence?

The condition that typically shows a "lumpy-bumpy" appearance of glomeruli on immunofluorescence is poststreptococcal glomerulonephritis. This distinct appearance is due to the deposition of immune complexes, which are generated in response to group A beta-hemolytic streptococcal infections. Upon immunofluorescence microscopy, one can observe granular deposits of immunoglobulin (particularly IgG) and complement (especially C3) along the capillary walls of the glomeruli, leading to the characteristic lumpy-bumpy pattern.

This pattern reflects the presence of these immune deposits and is an essential feature in the diagnosis, helping to differentiate it from other types of glomerulonephritis. In contrast, other conditions such as IgA nephropathy, membranous nephropathy, and diffuse proliferative glomerulonephritis exhibit different patterns and mechanisms, lacking the classic lumpy-bumpy appearance characteristic of poststreptococcal glomerulonephritis.