- Characteristics of Neoplastic Cells:
- Benign tumors
- Malignant tumors
- Gross appearance of tumors
What is Neoplastic?
A neoplasm is an abnormal growth of cells, also known as a tumor. Neoplastic diseases are conditions that cause tumor growth. Growth can be good (no cancer) or bad (cancer).
Benign tumors usually grow slowly and cannot spread to other tissues. Conversely, harmful plants can grow very slowly, but they can also grow very fast depending on the type of plant. Dangerous plants carry the risk of metastasis or proliferation of tissues and organs.
- Fundamental to the origin of all neoplasms is loss of responsiveness to normal growth controls.
- Behave as parasites and complete with normal cells and tissues for theiR metabolic needs.
- They are transformed, or they continue to grow regardless of normal regulatory controls.
- They steadily increase in size regardless of their local environment and nutritional status of host.
- Some neoplastic cells require endocrine support.
- They are depend on host for their nutrition and blood supply.
- 1.Pleomorphism (variation in cell size and shape).
- 2.Hyperchromatic (deeply staining) and abnormally large nuclei.
- 3.Increased mitotic figures with normal patterns.
- 4.Mitoses in abnormal locations within epithelium.
- 5.Architectural anarchy of cells. (Anarchy = confusion or disorder).
Differentiation of parenchymal cells is the extent to which parenchymal cells
resemble their normal forebears, both morphologically and functionally.
- Well-differentiated cells:
- 1)resemble very closely their normal counterparts morphologically and
- 2)mitoses are scant in number and are of normal configuration.}
- Benign tumors :composed of well-differentiated cells, remain localized,
- cannot spread to other sites, and are amenable to local surgical removal and patients survive.
- Malignant tumors:(Cancers) – exhibit wide range of differentiation of
- parenchymal cells, from well-differentiated to completely undifferentiated of anaplastic cells
- Anaplasia:a (dedifferentiation) – is a loss of structural and functional
- differentiation of normal cells.
- Characteristics of Anaplastic Cells:
- 1.They display marked pleomorphism.
- 2.Their nuclei are hyperchromatic and large with nuclear-cytoplasmic ratio of 1:1
- (normal is 1:4 or 1:6).
- 3.Their nuclei are variable and bizarre in size and shape.
- 4.Their chromatin is coarse and clumped.
- 5.Thier nucleoli are of astounding size.
- 6.Mitoses are numerous and atypical.
- 7.Anaplastic cells fail to develop recognizable patterns of orientation to each other;
- they may grow in sheets, with loss of communal structures.
- 8.Anaplastic calls may form giant cells.
- 9.Loss of functions of anaplastic cells is correlated with the degree of anaplasia;
- the more anaplastic a tumor, the more loss of specialized functions.
Gross appearance of tumors
1.Localization: in all organs and tissues of the body.
2.Sizes: are different – from small to giant.
Types of growth:
1)Expansive – tumor has regular border enclosing fibrous capsule
2)Invasive – without regular borders, not encapsulated; tumor progressive
infiltrate, invade the surrounding tissue.
In hollow organs:
1)Exophytic – into the lumen of organ
2)Endophytic – into the wall of organ
Depending of the number of foci
1)Unicentric – one focus of tumor growth
2)Multicentric – many foci of growth
In compact organs and in the wall of hollow organs: a)node, b)cyst;
2)At the surface of skin and mucous membranes: a)plaque, b)polyp, c)fungus.
5.Surface of tumor:
1)Smooth, 2)Irregular, including with finger-like projections.
6.Color of tumor:
1)White, 2)Yellow, 3)Grey, 4)Pink.
7.Consistence of tumor:
8.Cut surface of tumor:
1)Homogenous, 2)With fibers structure, 3)With areas of necrosis, hemorrhages,
calcification and accumulation of mucin.
s – development of secondary implants (foci, metastases)
discontinuous with primary tumor. This is sign of maliganat tumors. In general, the
more anaplastic and the
larger the primary neoplasm, the more likely is metastatic spread.
Malignant tumors disseminate by one of three pathways:
1.Seeding within body cavities:
a)carcinoma of colon may penetrate the wall of intestine and reimplant at distant
sites in peritoneal cavity;
b)lung cancers may cover pleural cavity;
c)ovarian cancers may cover peritoneal surfaces widely.
2.Lymphatic spread – movement of neoplastic cells by lymph: more typical of
Example: lung carcinomas arising in respiratory passages metastasize first to
regional bronchial lymph nodes and than to tracheobronchial and hilar nodes.
Reaction of lymphoid tissue to metastasis: necrotic products of neoplasm and
tumour antigens evoke reactive changes in lymph nodes, causing:
1)Lymphadenitis – enlargement and hyperplasia of lymphoid follicles;
2)Sinus histiocytosis – proliferation of macrophages in the subcapsular sinuses.
3.Hematogenous spread – movement of neoplastic cells by blood: it is the favored
pathway for sarcomas, but carcinomas use it as well. Arteries are less readily
penetrated than are veins. The liver and lungs are most frequently involved
secondary sites in hematogenous dissemination:
a)all portal area drainage flows to the liver (stomach, intestine, spleen);
b)all caval blood flows to the lungs (other organs)
Tumors of intermediate malignancy
Some tumors such as: 1)basal cell carcinoma of skin,
2)ameloblastoma (from enamel organ of tooth),
3)giant cell tumor of bone.
Characteristics: 1)Histologic structure – anaplastic;
2)Growth – locally invasive and slowly;
3)Metastasis – absent;
4)Recurrence – sometimes occur.
Predisposing factors of neoplasms:
1.Age. Increased incidence of cancer with age is due to:
1)accumulation of somatic mutations,
2)decline in immune competence.
2.Geographic factors. Incidence and death rates for some are different in different
countries due to difference in environmental influences.
3.Environmental influences: ambient environment, work place, food, personal
4.Heredity. Some cancers are hereditary.
5.Acquired preneoplastic disorders: contain clinical conditions that predispose to
development of malignant neolasms:
1)persistant regenerative cell replication (long standing unhealed skid wound →
squamous cell carcinoma);
2)hyperplastic and dysplastic proliferations (atypical endometrial hyperplasia →
3)chronic inflammation (chronic gastritis → gastric carcinoma,
chronic colitis → colon carcinoma);
4)metaplasia (columnar epithelium → squamous epithelium in chronic bronchitis
leukoplakia of cervix of uterus → carcinoma).
Morphogenesis of neoplasms (Stages of tumor development):
Carcinoma in situ (anaplastic changes are marked and involve
the entire thickness of epithelium)
Histogenesis of neoplasms (Histological origin of tumor):
Determination of histogenesis – great significance in diagnosis of tumors:
Benign tumors – not difficult to determine of histogenesis;
Malignant tumors – especially poor-differentiated – very diffucult or
sometimes – unimpossible.
Correct diagnosis → Correct treatment
Etiology of Cancer (Carcinogenic agents):
1)Direct-acting carcinogens – chemicals which can directly cause cancers:
antineoplastic drugs (cyclophosphamide, chlorambucil etc.) – additional
effect of drugs;
2)Indirect-acting carcinogens – chemicals which require metabolic conversion
to become carcinogenic:
a)polycyclic and heterocyclic aromatic hydrocarbons
b)aromatic amines, amides and azo-dyes (naphthylamine);
3)Natural plant and microbial products:
aflatoxin B1 – aspergillus flavus – mushroom;
4)Others: a)asbestose, metals (chromium, arsenic, nickel),
1)Ultraviolet ray of sunlight;
3)Rays produced by nuclear fission reactions;
1)RNA-oncogenic viruses: human T-cell leukemia virus type 1.
a)human papilloma virus,
b)Epstein-Barr virus (cause Burkitt’s lymphoma),
c)hepatitis B virus.
Carcinogenesis (Pathogenesis of Cancer)
Carcinogenesis(Pathogenesis of Cancer)
Target molecules (chiefly DNA)
Permanent DNA damage
Clonal proliferation of altered cells
Additional mutations (progression)
Epidemiology of neoplasms:
Epidemiology – distribution of disease in human community, deals with
incidence (frequency of disease).
Distribution of Cancer:
Kyrgyzstan: M – Stomach, Lung, Liver, Skin, Esophagus;
F – Breast, Uterus, Stomach, Ovary;
USA: M – Prostate, Lung, Colon, Melanoma;
F – Breast, Lung, Colon, Uterus;
Russia: M – Lung, Prostate, Skin, Stomach, Colon;
F – Breast, Skin, Uterus, Colon, Stomach;
Classification of Neoplasms (WHO)
1.Epithelial tumors (nonspecific).
2.Tumors of exocrine and endocrine glands and epithelial surfaces (specific).
4.Tumors of nervous system and meninges.
5.Tumors of blood system.