Thymic Hyperplasia

Excerpt

The thymus got its role in T-cell differentiation discovered a few decades ago before the 1960s it was considered vestigial. Though largely known as a lymphoid organ and for its role in T-cell differentiation, thymus also has an endocrine role that includes manufacturing thymosin that regulates T-cell differentiation and other humoral factors that regulate cell growth, maturation and guide the process of mineralization. The thymus is the principal location for T-cell lymphopoiesis. The production of functional T-cell is choreographed by thymic epithelial cells that guide them in proliferation, maturation, and survival. The thymic epithelial cells are compartmentalized into two main populations medullary thymic epithelial cells and cortical thymic epithelial cells. These populations are further segregated into distinct subpopulations having specific molecular and functional roles.

Thymic hyperplasia alludes to an increase in the size of thymus due to an increase in the number of cells. Thymus achieves its peak size around puberty and then atrophies slowly. Thymic hyperplasia is not always pathological, but the growth of the thymus to a certain degree not anticipated for a patient’s age raises the alarm and should lead to further investigation.