1. Oncology
• 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.

2. Classification of Neoplasms
Tissue Origin
Benign
Malignant
395-4
Examples
Epithelial
Glandular
Adenoma
Squamous
and
Transitional
Polyp,
papilloma
Connective
tissue
Tissue type +
suffix (-oma)
Hematopoietic
&
lymphoreticular
Neural tissue
Thyroid follicular
adenoma
Adenocarcinoma of lung
Squamous cell carcinoma Squamous papiloma of
skin
Transitional cell
carcinoma
Squam. cell carcinoma
skin
Osteoma,
Sarcoma
Osteosarcoma,
Hemangioma,
Hemangiosarcoma
Adenocarcinoma
Lymphoma
Leukemia
Neuroma
Neurofibroma
Mixed tissues of Teratoma
Large cell lymphoma
Hodgkin’s disease
Mylocytic leukemia
Sarcoma
Blastoma
Glioblastoma multiforme
Neurofibrosarcoma
Teratocarcinoma
Teratoma of ovary

3. Histogenetic classification of benign tumors
Normal tissue
Resultant Benign
tumor
Glandular epithelium Adenoma
Surface epithelium
Papilloma
Fibroblasts
Fibroma
Cartilage
Chondroma
Striated Muscle
Rhabdomyoma
Smooth Muscle
Leiomyoma
Blood Vessels
Hemangioma
Fat
Lipoma
Bone
Osteoma
Liver
Hepatoma
642-1

4. Histogenetic classification of malignant tumors
Normal tissue
Epithelium
Connective tissue
Bone Marrow
Resultant Malignant
tumor
Carcinoma
Sarcoma
Leukemia
More Specifically:
Glandular epithelium
Squamous epithelium
Fibroblasts
Cartilage
Striated Muscle
Smooth Muscle
Endothelium
Fat
Bone
Liver
Adenocarcinoma
Squamous carcinoma
Fibrosarcoma
Chondrosarcoma
Rhabdomyosarcoma
Leiomyosarcoma
Angiosarcoma
Liposarcoma
Osteosarcoma
642-2(1)
Hepatocellular carcinoma

5. Sarcoma/carcinoma
• A sarcoma is a cancer
that arises from
transformed cells of
mesenchymal origin.
Thus, malignant tumors
made of cancerous
bone, cartilage, fat,
muscle, vascular, or
hematopoietic tissues
are, by definition,
considered sarcomas.
• Malignant tumor
originating from
epithelial cells, which
are termed carcinoma.
Common malignancies,
such as breast, colon,
and lung cancer, are
almost always
carcinoma.

6. Charateristics of neoplastic cells
 Abnormal size and irregular shape of cells.
 Nuclei
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

7. 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.

8. 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

12. Benign tumor
Capsule

15. Smooth muscles

17. Here is an osteosarcoma of bone. The large, bulky mass
arises in the cortex of the bone and extends outward

18. This is an example of metastases to the liver, tan-white
masses are multiple and irregularly sized.

23. Mitotic figures

24. 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.

26. • 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.