Abnormality of the immune system thymus atrophy atrophied thymus atrophic thymus Acquired diminution of the size of the thymus associated with wasting as from death and reabsorbtion of cells, diminished cellular proliferation, decreased cellular volume, pressure, ischemia, malnutrition, reduced function or malfunction, or hormonal changes. MP:0003644 thymic atrophy Eirini Petsalaki