abnormal numbers of the ovarian follicle in which the primary oocyte attains its full size and is surrounded by an extracellular glycoprotein layer (zona pellucida) that separates it from a peripheral layer of follicular cells permeated by one or more fluid-filled antra; the primary oocyte occupies the cumulus oophorus while the theca of the follicle develops into internal and external layers (Mammalian Phenotype Ontology, MP_0011127)
