L4 - Overview of Neoplasia History and Classification Flashcards
Tumour
Swelling. Commonly used to describe neoplasia.
Neoplasm
A new and abnormal growth of tissue in a part of the body, especially as a characteristic of cancer
Hyperplasia
- Increase in number of cells.
* Benign, usually not neoplastic, reversible.
Hypertrophy
- Increase in size of cells
- No increase in number of cells
- May be physiological or pathological
- Not neoplastic
- e.g. skeletal muscle, cardiac muscle
Metaplasia
- Change from the normal cell type, to another cell type, in response to stimuli, usually noxious.
- Not neoplastic, but if the stimulus persists, may progress to neoplasia in some circumstances.
Dysplasia
- Abnormal cell growth.
- May be neoplastic and pre-malignant.
- May regress
- e.g. Colon adenoma.
Eponymous tumours
- Hodgkin lymphoma
- Burkitt Lymphoma
- Ewing sarcoma
- Kaposi sarcoma
Other neoplasms
• Melanoma, Lymphoma, Neuroblastoma, Nephroblastoma
Differentiation
- The extent to which tumour cells recapitulate normal cells in structure and/or function.
- Benign tumours are generally well differentiated, and are only recognised as tumours because of formation of an abnormal mass, or abnormalities in hormones or genetics
- Malignant tumours are classified as well, moderately, poorly differentiated, or undifferentiated/anaplastic.
Pleomorphism
- Variation in size and shape of the cell or the nucleus (or both).
- Pleomorphism increases with loss of differentiation.
Nuclear atypia of neoplastic cells
- Hyperchromasia
- Change in nuclear cytoplasmic ratio
- Mitotic activity
- Loss of polarity
Hyperchromasia
Dark nuclei due to increased amount of chromatin, in same volume of nucleus. (Increased “blueness” on H+ E stained sections).
Change in nuclear cytoplasmic ratio
Usually increased, ie the nucleus increases in size in relation to the cytoplasm
Mitotic activity
Usually more helpful in malignant tumours. Particularly if bizarre mitoses are present
Loss of polarity
Some cells shows polarity of the nucleus (eg glandular epithelial cells). In neoplasia, the cells may lose this polarity.