Neoplasm

1

• Neoplasm

2
Neoplasm

• It is synonymously used with tumor.
• It is a new abnormal growth because of abnormal
  cellular - reproduction.
• Aberrant cellular growth-An alteration in normal
  cell growth.
• Tumor - A growth of neoplastic cells cluster
  together to form a mass. It can be benign or
  malignant.

3
Cont

• Benign tumor is characterized by abnormal cell
  division but no metastasis or invasion of the
  surrounding tissues.
• Malignant tumor abnormal cell division
  characterized by ability to invade locally,
  metastasize and reoccur. It is cancer cells.

4
Cont

• Carcinogenesis is the production or origination
  of cancer cells.
• Sarcoma - Malignant growth from mesodermal
  tissues
• I.e. connective tissues, blood-vessels, organs,
  etc.
• Metastasis - Ability to establish secondary
  tumor growth at a new location away from the
  primary tumor.
• Carcinoma - Malignant growth originating in
• epithelial tissues

5
Cont

• Every time a normal cell passes through a cycle
  of division, the opportunity exists for it to
  become Neoplastic.
• N.B. Cancer cell lack control of Mitosis.
• The three leading death producing cancer
• in men are cancer of the lung, colo-rectal and
  prostatic gland.
• For women the most common cancers are those of
  the breast, lung, and colorectal.

6
Classifications of Neoplasms

• Neoplasms are classified according to their cells
  of origin and their behavior of growth as benign
  or malignant.

7
Comparison of benign malignant Neoplasms

• Benign

• Malignant

• Similar to cell of origin
• Compress locally
  
• Slow growth rate
  
• Seldom recur after removal by surgery
• Necrosis and ulceration is uncommon
• Systemic effect is uncommon

• Dissimilar from cell of origin
• Invade locally
• Rapid to very rapid growth rate
• Frequently recur after removal
• Necrosis and ulceration common
• Systemic effect is common

8
Nomenclature of Neoplasms

• Naming of Neoplasia based on two main important
  features of the tumor.
• Based on its Behavior of growth
• i) Benign -
• Add oma at the end for connective tissue origin
  tumors.
• Add papiloma for epithelial origin.
• Add adenoma for glandular origin.

9
Cont

• ii) Malignant
• Add sarcoma at the end for malignant tumors of
  connective tissues origin.
• Add carcinoma at the end for malignant tumors
  of epithelial origin.
• Add adenocarcinoma at the end for malignant
  tumors of glandular origin.

10
Cont

• B) Based on cells of origin
• Neoplasms are named at their prefix by their
  cells of origin and their suffixes are added at
  the end to show whether they are benign or
  malignant.

11
Cont

• Examples Behavior of growth
• Cells of origin Benign
  Malignant
• Fatty cells Lipoma
  Liposarcoma
• Bone cells Osteoma Osteosarcoma
• Bld/vessels Hemangioma Hemangiosarcoma
• Fibrous tissues Fibroma Fibrosarcoma

12
Exceptional Naming (Malignant Misnomers)

• There are some neoplasms that are named
  exceptionally to the above rules.
• Examples-
• Hepatoma - malignant tumors of the liver cells.
  It is also called Hepato-cellular carcinoma
• Hodgkins disease - Malignant tumors of the
  lymphoid tissues.
• Multiple myeloma - Malignant tumors from the
  plasma cells.
• - Others- Leukemia, Ewings sarcoma, etc.

13
Mechanisms of carcinogenesis

• There are large numbers of research done in the
  world to know the etiology of cancer but none of
  the theories that attempt to explain the
  peculiarities of the cancer cells have been
  completely successful.
• The following are some of the theories on
  carcinogenesis
• a. Genetic Instability-
• The theory of somatic cell mutation supports the
  concept that mutational carcinogenic agents and
  heredity susceptibility can induce genetic
  abnormalities.

14
Cont

• b. Carcinogens
• Carcinogens are those substances that are capable
  of inducing neoplastic growth.
• They are also called oncogenes.
• Some substances induce neoplastic growth at
  higher doses and exposure rates while others can
  be carcinogenic at lower doses and exposure rate.

15
The three commonly encountered carcinogens are

• Chemical carcinogens
• Polycyclic aromatic hydrocarbons
• Present in tobacco smoke, automobile exhaust
• Usually cause cancer of lips, oral-cavity, lungs,
  neck and pancreas.
• Aromatic amines
• Found in insecticides, certain foods and
  naphthalene
• Alkylating agents
• Therapeutic agents - e.g. nitrogen mustard
• Others
• Aflatoxines, nitrosamides, drugs, etc.

16
Cont

• 2. Physical carcinogenic agents
• Ionizing radiations e.g. leukemia b/c of atomic
  bomb
• 3. Viral carcinogens (oncogenic viruses)
• Examples
• EBV (Epstein-Barr virus)- Burketts lymphoma
• HPV (Human-Papilloma-Virus)- Cervical cancer
  skin papilloma
• Hepatitis B virus