How does compensatory hypertrophy differ from regrowing a missing organ part?

Compensatory hypertrophy and the regeneration of missing organ parts are distinct biological responses to the loss of tissue.

• Regrowing a missing organ part: This process involves the replacement or restoration of the specific lost structures. In many organisms, this may result in the growth of a new structure on the stump of the old one, effectively replacing the amputated portion.1
• Compensatory hypertrophy: In this process, the missing structures are not replaced. Instead, the remaining portion of the organ increases in size to restore the original function of the organ. This reaction requires that some portion of the original structure remains to respond to the loss.1

The enlargement seen in compensatory hypertrophy occurs through an increase in cell size (hypertrophy), an increase in the rate of cell division (hyperplasia), or a combination of both. For example, if a portion of the liver is removed, the residual lobes grow until they reach a mass equivalent to the original organ, rather than regenerating the specific missing lobes.21