Cancer

Cancer is a leading cause of mortality and morbidity. It keeps pathologists busy.

This article deals with general concepts in cancer. Specific forms of cancer are described by the site from which they arise. This article discusses cancers of unknown primary.

Definition of cancer

Robbins definition of cancer:

• Tumour with the capacity to:
  1. Invade (infiltrate) and destroy adjacent tissue.
  2. Spread to other sites (metastasize).

Notes:

1. Tumour = abnormal mass of tissue.
   • Neoplasm = literally "new growth"; used interchangeably with tumour.

Tumours

Tumours per Robbins consist of:

1. Clonal expansions.
2. Stromal components - controlled by the clonal component.

Clinical features of cancer

• Uncontrolled growth.
• Direct invasion/destruction of tissue.
• Metastases.

Theory

• Cancer results from an accumulation of driver mutations.
  • It is thought that approximately seven driver mutations are required.

Cancers of unknown primary

Clinical history

1. Past history of cancer, i.e. is it a recurrence?
2. Family history of cancer?
3. Symptoms/presentation.
4. Occupation & documented exposures.
5. Impression from clinician(s).

Radiology/gross pathology

1. Location of lesion(s).

Pathologic features

1. Histomorphologic characteristics - see Basics article.
2. Special stains.
3. Immunohistochemistry.
4. Molecular pathology.

See also

• Hamartoma.
• Choristoma.