What term refers to a new formation or growth, particularly in the context of a tumor?

Neoplasia is the term that specifically refers to the process of new formation or growth, particularly in the context of tumors. It describes the abnormal and excessive proliferation of cells, which can form masses or tumors that may be benign (non-cancerous) or malignant (cancerous). In the realm of medical terminology, neoplasia is crucial for understanding various cancers and their behavior.

Metaplasia describes a reversible change where one differentiated cell type is replaced by another cell type, usually as an adaptive response to stress or injury. While it involves changes in cell types, it does not pertain to the formation of new growths in the same way neoplasia does.

Hyperplasia refers to an increase in the number of cells in a tissue or organ, leading to its enlargement. It can be a normal physiological response (like in glandular tissue during lactation) or pathological, but it does not refer to the formation of a new growth or tumor, as neoplasia does.

Hypoplasia indicates incomplete or underdeveloped tissue or organ, resulting in fewer cells than expected. This condition reflects a developmental issue rather than an active growth process, distinguishing it from the concept of neoplasia that is focused on new growth formation.