Which medical condition is associated with excessive tissue growth?

The medical condition associated with excessive tissue growth is hyperplasia. Hyperplasia refers specifically to an increase in the number of cells in a tissue or organ, leading to an expansion of its volume. This process can occur in various tissues in response to stimuli, such as hormonal changes or increased demand for that particular tissue's function.

For instance, in the case of hormonal stimulation, we often see hyperplasia in glandular tissues, such as during the menstrual cycle when the endometrial lining of the uterus thickens. This condition can be benign or related to disease processes, depending on the context and the tissue involved.

Atrophy, on the other hand, is the opposite process, characterized by a decrease in tissue size due to loss of cell numbers or size. Hypertrophy involves an increase in cell size rather than number, which is a different mechanism of tissue growth. Hypoplasia refers to an underdevelopment or incomplete development of a tissue or organ, resulting in a smaller than normal size. Each of these terms reflects different processes that affect tissue growth, but hyperplasia is specifically tied to an increase in cell number, making it the correct answer in this context.