Life and health

Extracorporeal photopheresis

Extracorporeal photopheresis, also called photopheresis, is an immunomodulatory therapy in which white blood cells are treated with a drug and UVA light outside the body, then reinfused.

Extracorporeal shockwave therapy

Extracorporeal shockwave therapy (ESWT) is a noninvasive treatment that delivers acoustic shock waves into injured musculoskeletal tissue, developed from kidney stone lithotripsy and used for plantar fasciopathy, tendinopathies, and nonunions.

Extract from tea tree

Extract from tea tree (tea tree oil, CAS 68647-73-4), Melaleuca alternifolia essential oil approved in the EU since 2009 as a greenhouse-only fungicide (Timorex Gold), a plant-based biopesticide with antifungal and insecticidal action.

Extracted seafood protein

Extracted seafood protein: protein recovered from fish, crustacean, or mollusk tissue and by-products via pH-shifting, solvent, or enzymatic extraction; covered by FDA GRN 147 for coatings and batters; central to allergen testing.

Oct 15, 2026

Extractive fermentation

Extractive fermentation, also called in situ product recovery (ISPR), is a bioprocess technique that removes inhibitory products such as ethanol or butanol from the broth as they form.

Extracutaneous mastocytoma

Extracutaneous mastocytoma (ORPHA:66662, ICD-10 C96.2) is an extremely rare benign, unifocal tumor of mature mast cells in organs other than skin, most often the lung; fewer than 10 well-documented cases exist and it was dropped from the WHO classification in 2017.

Extrafusal muscle fiber

Extrafusal muscle fibers are the ordinary force-generating skeletal muscle fibers outside the muscle spindles, innervated by alpha motor neurons in motor units, arranged in parallel with intrafusal spindle fibers, and typed I, IIa, IIb, IIx.

Extragonadal germinoma

Extragonadal germinoma (ORPHA:182127), also called extragonadal seminoma, is a rare malignant germ cell tumor of midline sites such as mediastinum, retroperitoneum, and pineal region, arising from abnormally migrated germ cells, mainly in young males, treated with radiation and cisplatin chemotherapy.

Extragonadal teratoma

Extragonadal teratoma (ORPHA:883) is a rare germ cell tumor arising outside the gonads, mainly in midline sites such as mediastinum, retroperitoneum, and sacrococcyx; mature forms are benign, immature forms aggressive in adults.

Extramammary Paget disease

Extramammary Paget disease (EMPD), also called extramammary Paget's disease, is a rare intraepithelial adenocarcinoma of apocrine-rich anogenital skin, first described by Crocker in 1889, treated surgically with lower recurrence after Mohs surgery.

Extramedullary hematopoiesis

Extramedullary hematopoiesis is the production of blood cells outside the bone marrow, mainly in the spleen, liver, and lymph nodes, often compensating for marrow failure.

Extramural venous invasion assessment

Extramural venous invasion (EMVI) assessment is the pathological and MRI evaluation of colorectal cancer for tumor cells in veins beyond the bowel wall, used for staging and prognosis.

Extraneural perineurioma

Extraneural perineurioma, or soft tissue perineurioma (ORPHA:100002), is a rare benign peripheral nerve sheath tumor of perineurial cells, EMA-positive and S100-negative, arising in subcutis of extremities or trunk, cured by excision.

Extranodal NK/T-cell lymphoma, nasal type

Extranodal NK/T-cell lymphoma, nasal type (ENKTCL): an aggressive EBV-associated non-Hodgkin lymphoma of cytotoxic NK or T cells, mostly nasal, common in East Asia and Latin America, treated with asparaginase-based chemoradiation.

Extraocular muscles

Extraocular muscles: the seven muscles per orbit (four rectus, two oblique, levator palpebrae superioris) that move the eye and lift the eyelid, innervated by cranial nerves III, IV, and VI, organized in global and orbital layers with connective tissue pulleys.

Extraoral Traction Appliances

Extraoral traction appliances are orthodontic devices, including headgear, face bows, and chincaps, that apply force from outside the mouth to move teeth or modify jaw growth.

Extraosseous plasmacytoma

Extraosseous (extramedullary) plasmacytoma, EMP, is a solitary tumor of clonal plasma cells in soft tissue outside bone marrow, mostly head and neck, treated with radiotherapy, distinct from extramedullary myeloma.

Extraperitoneal inguinal hernia repair

Extraperitoneal inguinal hernia repair is a surgical technique that places mesh in the preperitoneal groin space without opening the peritoneal cavity, including the laparoscopic TEP repair.

Extrapleural pneumonectomy

Extrapleural pneumonectomy (EPP) is a thoracic operation removing the pleura, one lung, pericardium, and hemidiaphragm en bloc, performed mainly for malignant pleural mesothelioma and carrying higher operative risk than lung-sparing pleurectomy.

Extrapyramidal symptoms

Extrapyramidal symptoms (EPS) are drug-induced movement disorders from dopamine D2-blocking antipsychotics: acute dystonia, akathisia, parkinsonism, and tardive dyskinesia, managed by dose reduction, anticholinergics, or VMAT2 inhibitors.

Extrapyramidal system

Extrapyramidal system: historical grouping of basal ganglia, substantia nigra, red nucleus, subthalamic nucleus and descending tracts outside the corticospinal tract; criticized as obsolete, tied to antipsychotic EPS, VMAT2 inhibitor treatments.

Extrarenal uraemia

Extrarenal uraemia (extrarenal uremia, ICD-10 R39.2, ICD-11 MF53) is elevated blood urea without intrinsic kidney disease, from prerenal low blood flow or increased urea production such as GI bleeding, sepsis, or high-protein catabolism.

Extraskeletal myxoid chondrosarcoma

Extraskeletal myxoid chondrosarcoma (EMC), also called NR4A3-rearranged myxoid sarcoma, is a rare slow-growing soft tissue sarcoma of the deep thigh and limb girdles, defined by pathognomonic NR4A3 gene fusions, most often EWSR1::NR4A3.

Extraterrestrial life

Extraterrestrial life is life originating outside Earth; none has been found. Astrobiology and SETI search via biosignatures and technosignatures on Mars, Europa, Enceladus, and 5,000+ exoplanets, with no confirmed detection in over 60 years.

Extravasation of urine

Extravasation of urine (urine leak, ICD-11 MF50.5) is leakage of urine outside the urinary tract from calyx to urethra, caused by trauma, iatrogenic injury, or obstruction; diagnosed by delayed-phase CT and often managed by observation or ureteral stenting.