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.
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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.
Classification of NeoplasmsTissue Origin Benign Malignant Examples
Epithelial
Glandular Adenoma Adenocarcinoma Thyroid follicular adenomaAdenocarcinoma of lung
• 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.
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
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 cells1. 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
Benign tumor
Capsule
Smooth muscles
Here is an osteosarcoma of bone. The large, bulky mass arises in the cortex of the bone and extends outward
This is an example of metastases to the liver, tan-white masses are multiple and irregularly sized.
Mitotic figures
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.