• The term oncology literally means a branch of
science that deals with tumours and cancers.
The word “onco” means bulk, mass, or tumor
while “-logy” means study.
• Neoplasm (from ancient Greek neo-, "new" +
plasma, "formation", "creation") or tumor is
an abnormal mass of tissue as a result of
abnormal growth or division of cells.
Classification of Neoplasms
Tissue type +
Adenocarcinoma of lung
Squamous cell carcinoma Squamous papiloma of
Squam. cell carcinoma
Mixed tissues of Teratoma
Large cell lymphoma
Teratoma of ovary
Histogenetic classification of malignant tumors
• A sarcoma is a cancer
that arises from
transformed cells of
Thus, malignant tumors
made of cancerous
bone, cartilage, fat,
muscle, vascular, or
are, by definition,
• Malignant tumor
epithelial cells, which
are termed carcinoma.
such as breast, colon,
and lung cancer, are
Charateristics of neoplastic cells
Abnormal size and irregular shape of cells.
Nuclei increase in size
Nucleolus (a) often prominent (b) sometimes multiple
(c) Atypical staining
Numerous mitotic figures
May be multiple----------tumour giant cells
Varying amount of cytoplasm (a) generally cytoplasm
decrease in amount (b) fibrillar appearance with few
secretory granules (c) basophilic in nature
Cytoplasm to nucleus ratio is lost
disturbed polarity of cells
Microscopic structure of tomour
Parenchyma; cells make up of the tumour
Cells of abnormal structure
deviation from normal is least in benign, somewhat
resemble normal tissue and marked in malignant
arrangement of tumour cells
1. Epithelial tumours (a) sheets or fronds in superficial
epithelium (b) clumps,columns or acini within a tumour
mass (c) Each cell fastened directly to the next.
2. Connective tissue tumours (a) Tumour cells lie singly,may
arrange in whorls or bundles (b) Each cell is separated
from the next by the intercellular substances
3. Hemopoitic tumours (a) tumour cells form (b) neoplastic
cells closely packed but remain discrete.
Microscopic structure of tomour
Stroma;Support and nourishes the tumour cells
Amount is variable
least in histoid tumours(A type of connective tumor that is
composed of a single type of differentiated tissue)
Reasonable in organoid tumours(A tumor that is glandular
in origin and that contains epithelium, connective tissue,
and other tissue structures that give it a complex structure
similar to an organ)
May be compact or edematous
Blood vessels vary in appearance
Tumour cells do not require innervation
What is the significance of mitotic
figures in a neoplasm?
• In general, their appearance suggests a higher
rate of cellular proliferation. Mitoses certainly
are present in normal tissues (surface
epithelia are constantly regenerating, and
hematopoiesis produces billions of new blood
cells each day). However, the presence of
mitoses, and particularly abnormal mitoses, in
a mass lesion supports a diagnosis of
neoplasia, and likely a malignant neoplasm.
• Hepatocellular carcinoma cells. Characterized by large anaplastic carcinoma
cells with eosinophilic cytoplasm, large hyperchromatic nuclei and
prominent nucleoli. The normal trabecular structure of the liver is distorted.
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