abnormal dentate gyrus morphology abnormal hippocampus region morphology abnormal hippocampus CA4 region morphology abnormal field CA4 of hippocampal formation abnormal dentate gyrus hilus morphology MP:0008269 any structural anomaly of the region of the hippocampal formation that is comprised of mossy cells that primarily receive inputs from granule cells in the dentate gyrus in the form of mossy fibers and from pyramidal cells in CA3, and send outputs into the dentate gyrus MPheno.ontology abnormal hilus of dentate gyrus morphology