In medicine, the word malignant is typically used to describe a cancerous growth of cells. Malignant is also used to describe a non-cancerous condition that is serious or life threatening. For example, dangerously high blood pressure is called malignant hypertension. Dangerously high internal body temperature is called malignant hyperthermia.
A group of cells are considered malignant when they have developed the ability to:
Malignant tumours can start anywhere in the body and the behavior of the tumour depends on many factors such as:
All of these factors are examined by your pathologist and documented in the pathology report.
Importantly, not all malignant tumours behave the same. For example, some tumours, despite being malignant, are slow growing and frequently cured while other malignant tumours are almost always fatal. The pathology report provides critical information which will allow your doctor to predict the behavior of the tumour and select the most appropriate treatment (prediction of behavior is referred to as prognosis).
There are many different types of malignant tumours. The type of tumour can only be determined after a tissue sample is examined under the microscope by a pathologist.
Common types of malignant tumours:
Some malignant tumours that have not yet spread into the surrounding tissue are called carcinoma in situ. These tumours are also called non-invasive and they are considered a precursor disease because they can turn into an invasive tumour over time.