I posted what I found from Wiki below. However, I though the a hypercellular glomeruli could also refer to any inflammatory process of the glomerulus.
This is primary, or secondary to SLE, viral hepatitis, hypocomplementemia. One sees 'hypercellular and hyperlobular' glomeruli due to proliferation of both cells and the matrix within the mesangium. Presents usually with a combined nephritic-nephrotic picture, with inevitable progression to end stage renal failure.
Hypercellular glomeruli typically means that there is mesangial hypercellularity though you can also get more of the tubular parietal cells in crescent formation which would also probably be referred to as hypercellular. The hypercellularity that is being referred to is often the inflammatory cells that have infiltrated the area rather than actual hyperplasia of the endogenous mesangial cells, though that can occur also such as in the membranoproliferative above.