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Neoplasm lecturer: Dr . Zainab Sajid Al- Shimmari. There are certain abnormal mass but not tumor abscess, granulomatus lesion this condition sub site when remove it cause also hyperplasia --- hyperatrophy cause abnormal mass disappear when remove it cause. Neoplasm:.
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There are certain abnormal mass but not tumor abscess, granulomatus lesion this condition sub site when remove it cause also hyperplasia ---hyperatrophy cause abnormal mass disappear when remove it cause
Neoplasm: Its a new growth of cell when 1-proliferation continuous without control . 2-bear considerable similar to its origin . 3-have no order structure arrangement . 4-not useful . 5-not clear understood causes .
Classification of neoplasm: There are 2 bases to classified the tumor : • histogenesis. • behaviour.
Histogenesis: mean that the tumor cell must be namedby the specific tissue or cell type from which it arise.
Behaviour: mean either harmless or dangerous if the tumor cell slow growth ,non invasion called benign e.g./fibroblast ------------fibroma But if the tumor cell is rapidly growth invade the tissue called malignant sarcom e.g./ fibroblast ----------fibrosarcoma. If it arised from epithelial tissue -- e.g. hepatic cell carcinoma --from liver Adenocarcinoma----- from glands.
Manner growth of tumor: • benign =growth by expansion • malignant = growth by expansion or by infiltration. The malignant cell destroid what cell in it bathway of continuous till it destryoed patient .
Q/ How can you classified tumor according to bases of hemogenesis and behavior?
Spread of tumor: Tumor will spread from it origin is malignant type which spread by: 1-infiltration by B.V., lymphatic V. 2-Spread by direct expansion 3-Metastasis tumor cell spread from origin to other parts of the body trough lymphatic V. to regional L.N. to general circulation
4-Invasion of B.V. There are 2 theory to growth of tumor cell in the new site: a-Soil theory:the tumor cell require the sutable cell to growth. b-Mechanical theory : the tumor cell growth in any tissue which reach to it. 5- Implantation : tumor cell may be metastasis through body cavities e.g. abdominal Cavity , pleura. thorax and implantation in them. The abd. Cavity lead to close the lymphatic V. and ascitis
Q/ Why the malignant tumor metastasis? • Decrease of adhesion between tumor cell. • Loss contact of migration inhibition • The tumor cell synthesis material(lipase. proteinaseas and collagenase) that destroid any normal cell in their bathway While the benign tumor not transmitted from their origin but growth by expansion.
Etiology of cancer: 1-chemical carcinogens 2-oncogenic DNA virus.suchas.Epstein-Barr Virus causes lymphoma,Hepatitis B virus Causes hepato cellular carcinoma. 3-oncogenic RNA virus.retrovirus. 4-disturbances in Hormones. 5-Physical causes.X-ray. 6-Parasites.Schisttosoma. 7-Chromosomal abnormalities. 8-Heredity.
Cytomorphology of Neoplastic Cells: (Differentiation and Anaplasia) The neoplastic cell is characterised by morphologic and functional alterations, the most significant of which are‘differentiation’ and ‘anaplasia’
Differentiation : is defined as the extent of morphological and functional resemblance of parenchymal tumour cells to corresponding normal cells. If the deviation of neoplastic cell in structure and function is minimal as compared to normal cell.
the tumour is described as ‘well-differentiated’such as most benign and low-grade malignant tumours.‘Poorly differentiated’, ‘undifferentiated’or ‘dedifferentiated’are synonymous terms for poor structural and functional resemblance to corresponding normal cell.
Anaplasia is lack of differentiation and is a characteristic feature of most malignant tumours. Depending upon the degree of differentiation, the extent of anaplasia is also variable i.e. poorly differentiated malignant tumours have high degree of anaplasia. As a result of anaplasia, noticeable morphological and functional alterations in the neoplastic cells are observed.
Loss of polarity. • Normally, the nuclei of epithelial cells are oriented along the basement membrane which is termed as basal polarity. This property is based on cell adhesion molecules, particularly selectins. Early in malignancy, tumour cells lose their basal polarity so that the nuclei tend to lie away from the basement membrane.
ii) Pleomorphism. The term pleomorphism means variation in size and shape of the tumour cells. The extent of cellular pleomorphism generally correlates with the degree of anaplasia. Tumour cells are often bigger than normal but in some tumours they can be of normal size or smaller than normal.
iii) N:C ratio. Generally, the nuclei of malignant tumour cells show more conspicuous changes. Nuclei are enlarged disproportionate to the cell size so that the nucleocytoplasmic ratio is increased from normal 1:5 to 1:1. iv) Anisonucleosis. Just like cellular pleomorphism, the nuclei too, show variation in size and shape in malignant tumour cells .
v) Hyperchromatism. Characteristically, the nuclear chromatin of malignant cell is increased and coarsely clumped. This is due to increase in the amount of nucleoprotein resulting in dark-staining nuclei, referred to as hyperchromatism. Nuclear shape may vary, nuclear membrane may be irregular and nuclear chromatin is clumped along the nuclear membrane.
vi) Nucleolar changes. Malignant cells frequently have aprominent nucleolus or nucleoli in the nucleus reflecting increased nucleoprotein synthesis. This may be demonstrated as NucleolarOrganiser Region (NOR) by silver (Ag) staining called AgNOR material.
vii) Mitotic figures. The parenchymal cells of poorly differentiated tumours often show large number of mitoses as compared with benign tumours and well-differentiated malignant tumours. As stated above, these appear as either normal or abnormal mitotic figures:
Normal mitotic figures may be seen in some non-neoplastic proliferating cells (e.g. haematopoietic cells of the bone marrow, intestinal epithelium, hepatocytes), in certain benign tumours and some low grade malignant tumours; in sections they are seen as a dark band of dividing chromatin at two poles of the nuclear spindle. Abnormal or atypical mitotic figures are more important in malignant tumours and are identified as tripolar, and multipolar spindles in malignant tumour cells.
viii) Tumour giant cells. Multinucleate tumour giant cells or giant cells containing a single large and bizarre nucleus, possessing nuclear characters of the adjacent tumour cells, are another important feature of anaplasia in malignant tumours. ix) Functional (Cytoplasmic) changes. Structural anaplasia in tumours is accompanied with functional anaplasia as appreciated from the cytoplasmic constituents of the tumour cells. The functional abnormality in neoplasms may be quantitative, qualitative, or both.
SPECIAL CATEGORIES OF TUMOURS: 1. Mixed tumours. When two types of tumours are combined in the same tumour, it is called a mixed tumour. For example: i) Adenosquamous carcinomais the combination of adenocarcinoma and squamous cell carcinoma in the endometrium. ii) Adenoacanthomais the mixture of adenocarcinoma and benign squamous elements in the endometrium. iii) Carcinosarcomais the rare combination of malignant tumour of the epithelium (carcinoma) and of mesenchymal tissue (sarcoma) such as in thyroid. iv) Collision tumouris the term used for morphologically two different cancers in the same organ which do not mix with each other. v) Mixed tumourof the salivary gland(or pleomorphic adenoma) is the term used for benign tumour having combination of both epithelial and mesenchymal tissue elements.
2. Teratomas. These tumours are made up of a mixture of various tissue types arising from the three germ cell layers—ectoderm, mesoderm and endoderm. Most common sites for teratomasare ovaries and testis (gonadalteratomas). But they occur at extra-gonadal sites as well, mainly in the midline of the body such as in the head and neck region, mediastinum, retroperitoneum. Teratomas may be benign or mature(most of the ovarian teratomas) or malignant or immature(most of the testicular teratomas).
3. Blastomas (Embryomas). Blastomas or embryomas are a group of malignant tumours which arise from embryonal or partially differentiated cells which normally form blastema of the organs and tissue during embryogenesis. These tumours occur more frequently in infants and children (under 5 years of age) and include some examples of tumours in this age group: neuroblastoma, nephroblastoma (Wilms’tumour), hepatoblastoma, pulmonary blastoma.
4. Hamartoma. Hamartoma is benign tumour which is made of mature but disorganized cells of tissues e.g. hamartoma of the lung consists of mature cartilage, mature smooth muscle and epithelium.Thus, all mature differentiated tissue elements which comprise the bronchus are present in it but are jumbled up as a mass.
5. Choristoma. Choristoma is the name given to the ectopic islands of normal tissue. Thus, choristoma is heterotopia but is not a true tumour.
Grading: Cancers may be graded grossly and microscopically. grading is largely based on 2 important histologic features: the degree of anaplasia, and the rate of growth. Based on these features, cancers are categorised from grade I as the most differentiated, to grade III or IV as the most undifferentiated or anaplastic. Malignant neoplasm are classified into 4 grades depending upon the degree of differentiation.
Grade I:Well-differentiated (less than 25% anaplastic cells) and composed of cells resembling the mature normal cells of the origin of the neoplasm. Grade II:Moderately-differentiated (25-50% anaplastic cells). Grade III:poorly-differentiated (50-75%anaplastic cells). Grade IV:undifferentiated or anaplastic (more than 75%anaplastic cells).
EPIDEMIOLOGY AND PREDISPOSITION TO NEOPLASIA CANCER INCIDENCE The overall incidence of cancer in a population or a country is known by registration of all cancer cases (cancer registry) and by rate of death from cancer. Worldwide, it is estimated that about 20% of all deaths are cancer-related; in US, cancer is the second most common cause of deaths, next to heart disease. There have been changing patterns in incidence of cancers in both the sexes and in different geographic locations.
In general, most common cancers in the developed and developing countries are: lung, breast, prostate and colorectal, liver, cervical and oesophageal. About one-third of all cancers worldwide are attributed to 9 modifiable life-style factors: tobacco use, alcohol, consumption, obesity, physical inactivity, low fiber diet, unprotected sex, polluted air, indoor household smoke, and contaminated injections
EPIDEMIOLOGIC FACTORS A) A large number of predisposing epidemiologic factors or cofactors which include a number of endogenous host factors and exogenous environmental factors. B) Chronic non-neoplastic (pre-malignant) conditions. C) Role of hormones in cancer.
A. Predisposing Factors 1. FAMILIAL AND GENETIC FACTORS. It has long been suspected that familial predisposition and heredity play a role in the development of cancers. In general, the risk of developing cancer in relatives of a known cancer patient is almost three times higher as compared to control subjects. Some of the cancers with familial occurrence are colon, breast,ovary, brain and melanoma. Familial cancers occur at a relatively early age.
2. ENVIRONMENTAL AND CULTURAL FACTORS. Surprising as it may seem, we are surrounded by an environment of carcinogens which we eat, drink, inhale. i) Cigarette smoking is the single most important environmental factor implicated in the etiology of cancer of the oral cavity, pharynx, larynx, oesophagus, lungs, pancreas and urinary bladder. ii) Alcohol abuse predisposes to the development of cancer of oropharynx, larynx, oesophagus and liver. iii) Alcohol and tobacco together . the risk of developing cancer of the upper orodigestive tract
iv) Cancer of the cervix . v) Penile cancer. vi) A large number of industrial and environmental substances are carcinogenic for some populations. These include exposure to substances like arsenic, asbestos, benzene, vinyl chloride, naphthylamine. viii) Certain constituents of diet have also been implicated in the causation of cancer. Overweight individuals, deficiency of vitamin A and people consuming diet rich in animal fats and low in fibre content are more at risk of developing certain cancers such as colonic cancer. Diet rich in vitamin E.
3. AGE. The most significant risk factor for cancer is age. Generally, cancers occur in older individuals past 5th decade of life, there are variations in age incidence in different forms of cancers. in advanced age is due to alteration in the cells of the host, longer exposure to the effect of carcinogen, or decreased ability of the host immune response. Some tumours have two peaks of incidence e.g. acute leukaemias occur in children and in older age group.
4. SEX. Apart from the malignant tumours of organs peculiar to each sex, most tumours are generally more common in men than in women except cancer of the breast, gall bladder, thyroid and hypopharynx. Although there are geographic and racial variations, cancer of the breast is the commonest cancer in women throughout the world while lung cancer is the commonest cancer in men. The differences in incidence of certain cancers in the two sexes may be related to the presence of specific sex hormones.