In histopathology, what does the term "differentiation" refer to?

Differentiation in the context of histopathology specifically refers to how much tumor cells resemble normal cells. This concept is essential in understanding the behavior and potential prognosis of a tumor. Well-differentiated tumors closely resemble their tissue of origin, maintaining many of the structural and functional characteristics of normal cells. In contrast, poorly differentiated tumors exhibit significant abnormalities and often do not resemble their originating tissue, which generally indicates a more aggressive disease process and a poorer prognosis.

The degree of differentiation is a critical factor in tumor grading, which helps predict how a tumor will behave and aids in determining the appropriate treatment strategy. Thus, the correct understanding underscores the importance of histological features in evaluating malignancies and guiding clinical decisions.