Final answer:
The 'spike and dome' pattern is observable under an electron microscope and indicates alternation in the glomerular basement membrane, typically associated with conditions like membranous nephropathy.
Step-by-step explanation:
The "spike and dome" pattern refers to a distinctive morphological feature observed in the glomerular basement membrane (GBM) of the kidney when viewed under an electron microscope. In conditions such as membranous nephropathy, a kidney disorder, the GBM develops abnormal spikes and dome-like structures.
What are normally smooth and consistent membranes appear to be thrown into sharp relief with protruding spikes intermingling with circular dome structures, indicative of immune complex deposition between the normal fibers of the GBM. This alteration can be seen with periodic acid-Schiff (PAS) staining, but electron microscopy provides a clearer image of the deposits and membrane thickening.