abnormal cell morphology abnormal cell nucleus morphology MP:0003111 MPheno.ontology abnormal nuclear compartment morphology abnormal nucleus morphology any structural anomaly of a membrane-bounded organelle of eukaryotic cells in which chromosomes are housed and replicated; in most cells, the nucleus contains all of the cell's chromosomes except the organellar chromosomes, and is the site of RNA synthesis and processing, but in some species, or in specialized cell types, RNA metabolism or DNA replication may be absent