has part has part has_part characteristic of has modifier abnormal thymus corticomedullary boundary morphology absent thymus corticomedullary boundary absent thymus corticomedullary junction MP:0013741 absent thymus CMZ absent thymus corticomedullary zone complete absence or loss of the dense region demarcating the thymus medulla from the surrounding cortex that is characterized by numerous blood vessels (predominantly arterioles) with some perivascular connective tissue, mature and immature T lymphocytes, dendritic cells, variable numbers of perivascular B-lymphocytes and plasma cells; normally, this is the site of entry of bone marrow stem cells and exit of mature, functional T cells absent thymic corticomedullary boundary absent thymus cortico-medullary zone absent thymus cortico-medullary junction absent thymus cortico-medullary boundary abnormal absent thymus corticomedullary boundary