Benign vs Malignant

Benign

Growth is slow

Malignant

Growth is rapid

Benign

Metaplasia (transformation to another tissue type)

Malignant

No metaplasia, usually anaplasia (loss of differentiation)

Benign

Growth is by expansion

Malignant

Growth is by infiltration

Benign

Encapsulation is the rule

Malignant

No encapsulation, often invasive

Benign

Metastases are lacking

Malignant

Metastases are present (spreads to distant tissues)

Benign

Growth is discrete and may be pedunculated (attached by a stalk)

Malignant

Growth is infiltrative, often spreading

Benign

Infiltration of surrounding tissue does not occur

Malignant

Infiltration of surrounding or distant tissue occurs

Benign

Differentiation of cells is prominent

Malignant

Anaplasia occurs (poorly differentiated cells)

Benign

Few mitotic figures (normal cell division)

Malignant

Many mitotic figures, often atypical (abnormal division)

Benign

Cells resemble normal tissue cells

Malignant

Cells may have enlarged nucleoli, hyperchromatism, and atypical mitotic figures