What does "anaplastic" specifically refer to in histopathological terms?

In histopathological terms, "anaplastic" refers to undifferentiated and abnormal cell features. This term is often used to describe tumor cells that have lost the specific characteristics and functions of their tissue of origin. Anaplastic cells typically exhibit a high degree of variability in size and shape (pleomorphism), an increased nuclear-to-cytoplasmic ratio, and abnormal mitotic figures. These features are indicative of aggressive behavior and a poor prognosis, as anaplastic tumors are often more difficult to treat and are associated with a higher likelihood of metastasis.

In contrast to well-differentiated cells, which maintain some characteristics of their original type, anaplastic cells show little to no resemblance to the normal cells they originated from. This lack of differentiation contributes to the aggressiveness of malignancies and highlights the importance of recognizing such changes when evaluating tissue samples.