Glossary of Medical Terms

Anemia – Any condition in which there is an abnormally low number of red blood cells or hemoglobin in the blood.


Angiogenesis – Formation or development of new blood vessels.


Angioma – A tumor (usually benign) whose cells tend to form blood vessels (hemangioma) or lymph vessels (lymphangioma); a tumor made up of blood vessels or lymph vessels.


Angiomatosis – A diseased state of the vessels with the formation of multiple angiomas.


Anomaly – An irregularity or deviation from normal; an abnormal structure.


Ascites – An accumulation of serous fluid in the abdominal cavity.


Benign – A non-cancerous or non-malignant tumor or growth.


Bilateral – Pertaining to both sides of the body.


Biopsy – The removal and examination, usually microscopic, of tissue from the living body, performed to establish precise diagnosis.


Bisphosphonates – A class of drugs that inhibits the resorption of bone. (Examples: pamidronate, alendronate, and zoledronate).


Bone Biopsy – The surgical removal of a sample of bone often from the hip for examination under a microscope.


Bronchoscopy – Examination of the bronchi through a bronchoscope.


Capillary – Any of the minute vessels that connect the arterioles and venules, forming a network in nearly all parts of the body. Their walls act as semi permeable membranes for the interchange of various substances, including fluids, between the blood and tissue fluid.


Cardiomegaly – Enlargement of the heart.


Cavernous lymphangioma – A deeply situated lymphangioma, composed of cavernous (hollow) lymphatic spaces, and always occurring in the neck or axilla.


Cervicothorax – From neck to thorax.


Chyle – The milky fluid taken up by the lacteals from the food in the intestine during digestion, consisting of lymph and droplets of triglyceride fat. It passes into the veins by the thoracic duct, becoming mixed with the blood.


Chylothorax – An accumulation of chylous fluid in the pleural space.


Chylous effusion – The leakage of chyle from the thoracic duct.


Chylous ascites – The presence of chyle in the peritoneal cavity as a result of anomalies, injuries, or obstruction of the thoracic duct.


Cisterna Chyli – A dilated sac at the lower end of the thoracic duct into which the intestinal trunk and two lumbar lymphatic trunks open.


Clinical Trial – In health care, including medicine, a clinical trial (synonyms: clinical studies, research protocols, medical research) is a process in which a medication or other medical treatment is tested for its safety and effectiveness, either in comparison to placebos or existing treatments. Clinical trials can be seen as the application of the scientific method to human health, because the researchers test hypotheses and observe what happens.


Computerized axial tomography scan (CAT Scan) – It is an x-ray procedure which combines many x-ray images with the aid of a computer to generate cross-sectional views and, if needed, three-dimensional images of the internal organs and structures of the body. A CAT scan is used to define normal and abnormal structures in the body and/or assist in procedures by helping to accurately guide the placement of instruments or treatments. A large donut-shaped x-ray machine takes x-ray images at many different angles around the body. These images are processed by a computer to produce cross-sectional pictures of the body. In each of these pictures the body is seen as an x-ray “slice” of the body, which is recorded on a film.


Congenital – Present at birth.


Cyst – An abnormal closed cavity or sac in the body, lined by walls called epithelium and containing a liquid or semisolid material.


Cystic hygroma – A rapidly growing sac or cyst of lymphatic origin, usually found in the neck, but can be found in the thorax.


DEXA Scan (Dual Energy X-Ray Absorbitometry) – A common method for measuring bone mass. The results of this test are usually reported as BMD or bone mineral density.


Dysplasia – Abnormality of development; in pathology, alteration in size, shape, and organization of adult cells.


Dyspnea – Labored or difficult breathing.


Effusion – The escape of fluid from the blood vessels or lymphatics into the tissues or a cavity.


Endothelial cell – A thin, flattened cell. A layer of them lines the inside surfaces of body cavities, blood vessels, and lymph vessels, making up the endothelium.


Epidemiology – The study of the various factors, patterns, and causes which determine the frequency of a disease on the human community.


Etiology – The cause (s) or origin of disease. Also used as a parameter of classification.


Extraosseous tissue – Occurring outside a bone or bones.


Fine Needle Aspiration – The removal of tissue or fluid with a needle for examination under a microscope. Also called needle biopsy.


Genetics – The study of heredity and its variation.


Hamartomatosis – The existence of multiple benign tumors resulting from an overgrowth of mature cells and tissues normally present in the affected part.


Hemoptysis – The spitting or coughing up of blood or blood-stained sputum.


Hepatomegaly – Enlargement of the liver.


Histology – The department of anatomy which deals with the minute structure, composition, and function of the tissues.


Idiopathic – Of unknown cause.


Lesion – Any pathological or traumatic discontinuity of tissue or loss of function of a part.


Ligation – The application of a ligature (any substance, such as surgical gut, cotton, silk, or wire, used to tie a vessel or strangulate a part)


Loculated pockets – Divided into small spaces or cavities


Lymph – A watery substance moving through the lymphatic network by way of vessels. Lymph is collected from all parts of the body and returned to the blood via the lymphatic system


Lymphangiogenesis – The formation of lymphatic vessels from pre-existing lymphatic vessels, in a method believed to be similar to blood vessel development or angiogenesis.


Lymphangiogram – X-rays taken of the lymphatic system using an injected dye to outline the lymphatic vessels and organs.


Lymphangioleiomyomatosis – (LAM) is a rare disorder resulting from proliferation in the lung, kidney, and axial lymphatics of a neoplastic cell having a smooth muscle cell phenotype (LAM cell).


Lymphangioma – Benign tumor representing a congenital malformation of the lymphatic system, made up of newly formed lymph-containing vascular spaces and channels. The main types are lymphangioma circumscriptum, cavernous lymphangioma, and simple lymphangioma.


Lymphangioma circumscriptum – Also referred to as cutaneous this is a “kind” of birthmark generally occurring in clusters. They resemble small blisters and range in color from pink to dark red. They are benign and usually require no medical treatment. For cosmetic reasons, some patients may choose to have them surgically removed. Lymphangioma simplex is often included in this type.


Lymphatic – Pertaining to lymph or a lymph vessel; the term is used alone to designate a lymphatic vessel or, in the plural, to designate the lymphatic system.


Lymphatic Malformation – One of several types of vascular malformations in the vascular anomaly class. The lymphatic system serves as a collection and active normal fluid transport mechanism for tissue fluids. It carries the drained near-clear fluid, collected from the body tissues, through a network of vessels that have valves and muscles to help keep the fluid moving. Together with the lymph nodes, this is called the lymphatic system. When the normal development of lymphatic channels is disturbed, a malformation occurs, resulting in abnormal, dilated lymph channels that can be either focal or diffuse. Fluid accumulates, and the affected lymphatic vessels enlarge, and a mass is seen. LM’s appear as sponge-like masses of abnormal channels and spaces containing this fluid. Gorham’s disease is a type of LM with multiple areas of bone degeneration, and involving surrounding soft tissue – which is thought to be due to the presence of vascular anomalies (lymphatic or lymphaticovenous) within the bone. There are 3 subtypes:

  • Microcystic LM – In the past commonly known as lymphangioma. Consists of mass like soft-tissue abnormalities.
  • Macrocystic LM – Previously called cystic hygroma. Appears as a large, soft, smooth, clear mass under normal or bluish skin. Consists of visible cystic spaces that contain lymphatic fluid. The term “cystic hygroma” was previously and commonly used for macrocystic lymphatic malformations in the neck.
  • Mixed LM – Consists of mass-like solid-appearing lesions accompanied by cystic lesions. Both may cause enlargement of any structure.

Lymphaticovenous – Connecting of veins and lymphatic vessels.


Lymphoscintigraphy – The use of radioactive tracers to identify the lymphatic drainage of a tumor. This technique is used to guide the surgeon in performing biopsies and in the removal of tumors.


Lymph vessel – The vessels in the body that carry lymph.


Magnetic Resonance Imaging (MRI) – The use of magnetic waves to make pictures of the inside of the body. Using a large magnet, radio waves, and a computer, an MRI produces two-dimensional and three-dimensional pictures. An MRI can be used to evaluate any part of the body.


Mediastinum – The area between the lungs. It contains the heart and pericardium, the bases of the great vessels, the trachea and bronchi, esophagus, thymus, lymph nodes, thoracic duct, phrenic and vagus nerves, and other structures and tissues.


Metastasis – Spread of tumor cells from one part of the body to another.


Neoplasm – New and abnormal growth; specifically a new growth of tissue in which the growth is uncontrolled and progressive. It has no useful function.


Osteoblast – A bone forming cell.


Osteoclast – A cell that breaks down bone and is responsible for bone resorption.


Osteolysis – The softening, absorption, and destruction of bony tissue, a function of the osteoclasts.


Palpable – Something that can be felt by touch.


Parenchyma – The essential working part of the organ that is concerned with the function.


Parietal Pleura – A membrane which lines different parts of the pleural cavity and is moistened with serous secretions. It also covers the side of the pericardium to the chest wall, and backward to the spine.


Pathological fracture – A bone broken, not by trauma alone, but so weakened by disease as to break with abnormal ease.


Pathology – The branch of medicine that deals with the essential nature of disease, especially of the structural and functional changes in tissues and organs of the body that cause or are caused by disease.


Peripelvic – About the pelvis.


Peritoneum – The membrane that lines the abdominal and pelvic cavities and covers most of the abdominal organs.


Pleura – The thin covering that protects and cushions the lungs. The pleura is made up of two layers of tissue that are separated by a small amount of fluid.


Pleural Cavity – A space between the parietal and visceral pleura that contains serous fluid.


Pleural effusions – Increased amounts of fluid within the pleural cavity.


Pleurectomy – Excision of a portion of the pleura.


Pleurodesis – A procedure that causes the membranes around the lung to stick together and prevents the buildup of fluid in the space between the membranes. This procedure is done in cases of severe recurrent pleural effusion (fluid around the lungs). An irritant (such as Bleomycin, Tetracycline, or talc powder) is instilled inside the space between the pleura (the two layers of tissue lining the lungs) in order to create inflammation which tacks the two pleura together. This procedure thereby obliterates the space between the pleura and prevents the re-accumulation of fluid.


Pneumothorax – An accumulation of air or gas in the pleural space.


Positron Emission Tomography (PET Scan) – A highly specialized imaging technique that uses short-lived radioactive substances to produce three-dimensional colored images of those substances functioning within the body.


Proliferation – The growth and reproduction of similar cells.


Protein losing enteropathy – The loss of protein in the intestine.


Radiotherapy – The treatment of disease by radiation.


Resorption – The process of losing a substance.


Simple lymphangioma – Lymphangioma composed of small lymphatic channels that tend to occur subcutaneously in the head and neck region or axilla and sometimes in internal organs. Superficial lesions present as slightly raised or sometimes nodular lesions; deeper lesions are sharply circumscribed, compressible, and gray to pink in color.


Splenomegaly – Enlargement of the spleen.


Subcutaneous – Beneath the skin.


Thorax – Part of the body between the base of the neck and the diaphragm.


Thoracic Duct – The main lymph duct of the body. It begins in abdomen and goes into the thorax, beside the aorta and the esophagus ending in the Left Subclavian Vein that receives lymph.


Thrombocytopenia – Abnormal decrease in the number of platelets circulating in the blood.


Ultrasound – An evaluation of an area using high-frequency sound waves that can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques.


Unilateral – Affecting but one side of the body.


Viscera – The internal organs of the body, specifically those within the chest (as the heart or lungs) or abdomen (as the liver, pancreas or intestines).


X-ray – A photograph-like image obtained by using small doses of radiation to obtain a picture.