Benign versus malignant

The determination of the behaviour of a tumour is vital for planning treatment and formulating a prognosis. Often, expert macroscopic inspection is an excellent guide to the type and progression of a tumour, but such provisional assessment must always be a prelude to formal pathological examination of a tissue sample.

Allowing for such variables as the degree of malignancy changing in time in one tumour, and some tumours showing little tendency for metastasis despite cellular abnormality, there are some general rules that can aid the clinician:

Tumour:

• a tumour is a commonly used, but non-specific, term for a neoplasm
  • tumour simply refers to a mass. This is a general term that can refer to benign (generally harmless) or malignant (cancerous) growths.

Benign Tumour:

• benign tumours are non-malignant/non-cancerous tumour
  • a benign tumour is usually localized, and does not spread to other parts of the body. Most benign tumours respond well to treatment
    • if left untreated, some benign tumours can grow large and lead to serious disease because of their size
    • benign tumours can also mimic malignant tumours, and so for this reason are sometimes treated

Malignant tumour

• malignant tumours are cancerous growths
  • may be resistant to treatment, may spread to other parts of the body and they sometimes recur after they were removed.

Generally, benign neoplasia has the suffix "-oma" whereas malignancy is denoted by a reference sarcoma or carcinoma. There are anomalies, e.g. traditional references such as Wilms' tumour, seminoma and mesothelioma - all are malignant. Teratomas are also classified according to their degree of differentiation into mature and immature.