2. Overview
• Neoplasia: new growth
• Neoplasm: mass of cells that composes the
new growth
• Growth disturbances in which the regulatory
mechanisms of cell contact inhibition,
differentiation, and mitosis are defective
• Hyperplasia, metaplasia, and dysplasia
3. Definitions-I
• Oncology: study of or science of neoplastic
growth
• Neoplasia: new growth
• Neoplasm: mass of cells composing the new
growth
• Tumor: any swelling (currently used almost
exclusively to refer to a neoplastic growth)
4. Definitions-II
• Cancer: common term used for all malignant
neoplasms
• Benign neoplasm: a neoplasm that tends to grow
slowly, is well differentiated, does not metastasize,
and is usually non-life threatening
• Malignant neoplasm: a neoplasm that tends to grow
rapidly, is poorly differentiated, often metastasizes,
and frequently causes death of the host
5. Definitions-III
• Metastasis: transfer of disease manifestations from
one organ to another. It is used mainly to refer to the
secondary growth of a malignant neoplasm in an
organ or site remote from the primary site
• Differentiation: process where by one form, typically
the immature, develops into another, usually the
mature. As it relates to cells, this generally involves
the development of immature cells into mature ones
8. Differentiation of Benign and
Malignant Neoplasms
• Degree of cellular differentiation or cellular
anaplasia
• Rate of growth
• Mode of growth and spread
• Anaplasia and metastasis are the "hallmarks"
of malignancy.
9. Nomenclature
• Mixed tumors:
– Pleomorphic adenoma of salivary gland
– Fibroadenoma of breast
• Teratoma: more than one germ-cell layer
– Teratoma contains: bone, epithelium, muscle,
fat, nerve….
10. Differentiation and Anaplasia
• Differentiation is the extent to which tumor cells
resemble their normal cells morphologically and
functionally
• Generally:
– Benign tumors are well differntiated
– Malignant tumors can be well differentiated,
moderately differentiated or poorly differentiated.
They can be “undifferentiated”
• Anaplasia is lack of differentiation
11. Differentiation
• Well-differentiated tumors contain cells
that resemble the normal cells of origin
• Poorly-differentiated or undifferentiated
tumors contain cells that do not resemble
their normal counterparts (ancillary studies
may be needed to determine the cell of
origin)
12. Features of Anaplasia
1. Pleomorphism (variation in size and shape of cells
and nuclei)
2. Hyperchromatism (nuclei contain abundance of
dark-staining chromatin)
3. Enlarged nucleoli
4. Increased mitosis with abnormal mitotic figures
5. Formation of tumor giant cells (in some
instances)
13. Rate of Growth
• In general:
– Benign tumors: slowly
– Malignant tumors: rapidly, sometimes at an erratic
pace, eventually to spread and kill the host.
• Mitosis
14. Metastasis
• Spread of neoplastic cells from one part of the
body to another
• Hematogenous
• Lymphogenous
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18. Grading and staging
• Grading is based on the microscopic
features of the cells which compose a
tumor and is specific for the tumor type.
• Staging is based on clinical, radiological,
and surgical criteria, such as, tumor size,
involvement of regional lymph nodes, and
presence of metastases. Staging usually
has more prognostic value.
19. Causes of Neoplasia
• Oncogenic viruses
• Carcinogenic chemicals
• Radiation
• Other agents
21. Carcinogenic Chemicals
• Dose-dependent, additive and irreversible
• Lag period
• Changes transmitted to daughter cells
• Enhancement by cellular proliferation
• Diversity in antigenic diversity as well as a diversity of
phenotypes in terms of histologic patterns, degree of
differentiation, cell surface properties and other
attributes of neoplastic transformation
24. General Characteristics of Neoplasia
• Morphology:
– Benign neoplasms tend to extend above the
surface of the skin or the organ
– Malignant neoplasms tend to be very irregular in
shape and to infiltrate the underlying tissue
• Metabolism:
– High rates of both aerobic and anaerobic glycolysis
25. Clinical Effects of Neoplasia-I
• Atrophy of surrounding cells
• Obstruction of the lumen or organs
• Destruction of blood or lymph supply
• Destruction of nerve supply
• Bacterial invasion of the neoplasm
26. Clinical Effects of Neoplasia-II
• Emaciation
• Anemia
• Excessive production of hormones
• Death of the individual
• Spontaneous regression and recovery
28. Treatment of Neoplasia
• Surgery
• X-rays
• Radium and other radioactive materials
• Endocrine products
• Chemicals
• Immunotherapy
29. Summary
• Neoplasia- an abnormal mass of tissue
which has lost its responsiveness to growth
controls
• Benign neoplasms tend to be slow-growing,
well-differentiated tumors which lack the
ability to metastasize
• Benign neoplasms, in general, remain
localized and are amenable to surgery
30. Summary
• Malignant neoplasms tend to be fast-
growing lesions which invade normal
structures
• Malignant neoplasms vary in the degree of
differentiation and some show anaplasia
• Malignant neoplasms are capable of
metastasis
31. Summary
• The prognosis of a patient with any type of
neoplasm depends on a number of factors
including: the rate of growth of the tumor,
the size of the tumor, the tumor site, the
cell type and degree of differentiation, the
presence of metastasis, responsiveness to
therapy, and the general health of the
patient.
