endocrinologist [en-do-crin ol-o-gist] A doctor specialising in the diagnosis and treatment of hormone disorders.

endometrial cancer [en-do me-tri-al can-cer] see uterine cancer.

endoscopy [en dos-co-py]/endoscope [en-do scope] Endoscopy is the procedure of looking inside the body using an endoscope, which is an instrument consisting of a thin, flexible tube with a light at the end that is inserted into a body opening (mouth, anus, vagina, urethra) to enable a direct view of structures inside the body. Many endoscopes can also be used to take a sample of tissue for biopsy, or to remove small growths: see fibre optics.

enema [en-e-ma] A procedure to wash out faeces from the bowel, to insert drugs for treatment, or, in the case of a barium enema , to examine the bowel under x-ray .

engraft When transplanted bone marrow begins to produce red blood cells, white blood cells and platelets.

enzyme Proteins that are essential for the normal functioning and performance of the body.

epidermis [ep-i-der-mis] One of two main layers that make up the skin. The epidermis is the surface layer, which contains basal cells, squamous cells—which contain keratin, a protective substance that resists heat, cold and the effects of many chemicals—and melanocytes—which produce keratin.

epidural anaesthetic [ep-i-du-ral an-aes-thet-ic] see anaesthetic.

esophagus [e-soph-a-gus] see oesophagus.

extravasation [ex-tra va-sa-tion] Where blood or lymph leaks and spreads from the vessels into the surrounding tissues, as a result of injury or allergy. Extravasation of chemotherapy drugs can occur when the drug leaks out of the vein when chemotherapy is being administered intravenously. Some chemotherapy can cause damage to the tissues around the site of extravasation.