4.classification

7/27/2019 4.Classification

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NOMENCLATURE


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Comparison between benign &

malignant tumor.


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AplasiaThe complete or partial failure of tissue or an organ todevelop.

AgenesisAgenesis means incomplete development, or the failure ofany part or organ of the body to develop normally.

AtrophyAtrophy occurs when normal tissue, an organ or even thewhole body wastes because the constituent cells die.Undernourishment, disease, injury, lack of use or AGEINGmay cause atrophy. Muscular atrophy occurs in certainneurological diseases such as POLIOMYELITIS or MUSCULARDYSTROPHY. The ovary (see OVARIES) atrophies at theMENOPAUSE.

HypertrophyThe increase in size which takes place in an organ as theresult of an increased amount of work demanded of it by thebodily economy. For example, when valvular disease of theheart is present, compensation occurs by an increase inthickness of the heart muscle, and the organ, by beatingmore powerfully, is able to overtake the strain thrown uponit. Similarly, if one kidney is removed, the other

hypertrophies or grows larger to take over the doubleworkload.

HyperplasiaHyperplasia means an abnormal increase in the number ofcells in a tissue.

Hypoplasia

Excessive smallness of an organ or part, arising fromimperfect development.


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CancerThe general term used to refer to a malignant TUMOUR,

irrespective of the tissue of origin. Malignancy indicatesthat (i) the tumour is capable of progressive growth,unrestrained by the capsule of the parent organ, and/or (ii)that it is capable of distant spread via lymphatics or thebloodstream, resulting in development of secondarydeposits of tumour known as metastases. Microscopically,cancer cells appear different from the equivalent normalcells in the affected tissue. In particular they may show alesser degree of differentiation (i.e. they are moreprimitive), features indicative of a faster proliferative rate

and disorganised alignment in relationship to other cells orblood vessels. The diagnosis of cancer usually depends uponthe observation of these microscopic features in biopsies,i.e. tissue removed surgically for such examination.

MesotheliomaA malignant tumour of the PLEURA, the membrane lining thechest cavity. The condition is more common in peopleexposed to asbestos dust. It may be asymptomatic or cause

pain, cough, and breathing troubles. Surgery orradiotherapy may be effective but often the disease hasspread too far before it is discovered. Mesotheliomaincurred as a result of contact with asbestos at work mayattract industrial COMPENSATION.

MetaplasiaThe term applied to a change of one kind of tissue intoanother. Although not usually harmful, it may be pre

cancerous if occurring in the cervix (neck of the womb orUTERUS), URINARY BLADDER, or lining of the airways(bronchi).

MetastasisMetastasis, and metastatic, are terms applied tothe processby which malignant disease spreads to distant parts of the

body, and also to the secondary tumours resulting from thisprocess. For example, a cancer of the breast may produce


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metastatic growths in the glands of the armpit; cancer of thestomach may be followed by metastases in the liver.Metastases are colloquially known as secondaries and theirspread occurs through the bloodstream, lymphatic systemand across the body cavities. Highly malignant tumours forexample, melanomas are especially prone to spread farand fast. (See CANCER.)

DysplasiaAbnormal development of cells, tissues or structures in thebody.

Polypusor polyp (plural: polypi). A general name applied to tumourswhich are attached by a stalk to the surface from which theyspring. The term refers only to the shape of the growth andhas nothing to do with its structure or nature. Most polypiare of a simple nature, although malignant polypi are alsofound. The usual structure of a polypus is that of a finefibrous core covered with epithelium resembling that of thesurrounding surface. The sites in which polypi are mostusually found are the interior of the nose, the outer meatus

of the ear, and the interior of the womb, bladder, or bowels(see POLYPOSIS).Their removal is generally easy, as they are simply twistedoff, or cut off, by some form of snare or ligature. (The tissueremoved should be checked for malignant cells.) Thosewhich are situated in the interior of the bladder or bowels,and whose presence is usually recognised because bloodappears in the urine or stools, require a more seriousoperation usually anendoscopic examination (see ENDOSCOPE).

PapillomaProliferation of epidermis or epithelium (see SKIN) to form atumour. Benign papillomas are common in the skin and aresometimes viral in origin. Papilloma of the urinary bladdermay cause HAEMATURIA.

Lymphoma


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A malignant tumour of the LYMPH NODES dividedhistologically and clinically into two types: Hodgkinsdisease, and non-Hodgkins lymphoma. Hodgkins disease orlymphadenoma was named after Thomas Hodgkin (17981866), a Guys Hospital pathologist, who first described thecondition.

4.classification

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