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29 Cards in this Set
- Front
- Back
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What are the two main parts which form the structure of a tumour ?
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The transformed neoplastic cells called the parenchyma and the supportive connective tissue and blood vessels called the stroma.
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What are the common macroscopic shapes of tumours ?
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1. Sessile
2. Polyp 3. Papillary 4. Fungating 5. Ulcerated 6. Annular |
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Define: Histogenic classification.
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Classification by cell of origin. It classifies a growth by the degree of histological resemblance to parent tissue and allows the tumour to be graded.
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Define: Tumour differentiation.
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The degree to which the tumour resembles histologically its cell or tissue of origin.
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Why is tumour grading important ?
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It gives us prognostic information about the patient so we can predict what the odds of survival are for the patient.
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What are the terms used to describe benign epithelial tumours ?
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Papillomas or adenomas.
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Which term is used to describe a malignant epithelial tumour ?
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Carcinoma.
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Which term is used to describe a malignant connective tissue tumour ?
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Sarcoma.
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List the name of a benign tumour of the following origin:
1. Fat 2. Cartilage 3. Striated muscle 4. Glandular epithelium |
1. Fat- Lipoma
2. Cartilage- Chondroma 3. Striated muscle - Rhabdomyoma 4. Glandular epithelium - Adenoma |
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List the name of a malignant tumour of the following origin:
1. Squamous epithelium 2. Glandular epithelium 3. Glandular epithelium with papillary growth pattern 4. Glandular epithelium with cystic growth pattern 5. Fat 6. Cartilage 7. Blood vessels |
1. Squamous epithelium - Squamous carcinoma
2. Glandular epithelium - Adenocarcinoma 3. Glandular epithelium with papillary growth pattern - Papillary adenocarcinoma 4. Glandular epithelium with cystic growth pattern - Cystadenocarcinoma 5. Fat - Liposarcoma 6. Cartilage - Chondrosarcoma 7. Blood vessels - Angiosarcoma |
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Define: Teratoma.
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A neoplasm formed of cells representing all three germ cell layers: ectoderm, mesoderm and endoderm. In their benign form they may contain teeth and hair and on histology they may contain respiratory epithelium, cartilage, muscle, neural tissue etc.
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Define: Blastoma.
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A neoplasm that simulates the embryological appearance of the organ in which it occurs.
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Define: Mixed tumours.
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Non organoid combinations of mature tissue types of 1 germ cell layer.
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Define: Carcinosarcoma.
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A combination between a carcinoma and a sarcoma as a result of collision of both tumours or differentiation from an original transformed cell.
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Define: Neuroendocrine tumour.
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Neoplasms that originate from cells of the diffuse endocrine system.
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Define: Cyst.
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An epithelium-lined structure/fluid-filled space that can either be neoplastic or non-neoplastic.
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Define: Hamartoma.
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A benign tumour-like lesion consisting of two or more mature cell types normally found in the organ in which it arises. It lacks the autonomy of a true neoplasm.
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What are the main features of a neoplastic transformation ?
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1. Cellular immortalisation
2. Abnormal DNA - Pleomorphism and hyperchromasia 3. More mitotic activity and loss of apoptosis 4. Abnormal metabolic activities and tumour products - Poor cellular cohesion; synthesize products; gene depression |
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What are the major types of tumour products ? Give an example of each.
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1. Substances appropriate to their origin - Keratin from squamous epithelium
2. Substances inappropriate to their origin - ACTH and ADH from small cell lung carcinoma 3. Fetal reversion substances - Carcinoembryonic antigen from adenocarcinomas 4. Substances required for growth and invasion - Angiogenic factores |
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Define: Carcinogenesis.
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Process that leads to transformation of normal cells to neoplastic cells through permanent genetic changes in the target cells.
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Define: Carcinogens.
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Carcinogens are environmental factors that are mutagenic and play a role in the development of neoplasia.
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What are chemical carcinogens ? Give an example.
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They are chemicals that are associated with the formation of neoplasms. These chemicals include:
Polycyclic aromatic hydrocarbons (lung cancer), Aromatic amines (bladder carcinomas), Nitrosamines (GIT carcinomas), Azo dyes (liver cancer), and Vinyl cholride (angiosarcoma). |
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Give examples of oncogenic virusses and their associated tumours.
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1. Human T-cell leukemia virus causes leukemia
2. Epstein-Barr virus causes: Burkitt's lymphoma, Hodgkin's lymphoma, B-cell lymphomas and nasophyrangeal carcinomas 3. HBV causes liver cancer 4. Herpes virus type 8 causes Kaposi's sarcoma |
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Define: Premalignant lesions.
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They are local abnormalities that increase the risk for a malignant tumour in that area.
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What are the steps of carcinogenesis ?
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1. Initiation: The event that induces genetic alteration
2. Promotion: The event stimulating clonal proliferation of transformed cell 3. Progression: The process culminating in malignant behaviour characterized by invasion and its consequences |
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List the genetic mechanisms of carcinogenesis.
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1. Telomerase expression - Prevent telomeric shortening and drives cell proliferation
2. Inactivation of tumour suppressor gene function removing inhibition of growth control 3. Oncogene activation sets up autocrine growth stimulation |
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What is the difference between caretaker and gatekeeper genes ?
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Caretaker - Maintain the integrity of the genome by repairing DNA damage.
Gatekeeper - Inhibit the proliferation or promote the death of cells with damaged DNA |
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Discuss the two-hit hypothesis with regards to carcinogenesis.
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The first hit - The inheritance of a defective tumour suppressor gene.
The second hit - The mutational loss of function of the normal allele with the normal suppressor gene. |
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Define: Oncogene.
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Genes driving the neoplastic behaviour of cells.
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