Principles Flashcards
What is the definition of metaplasia?
A REVERSIBLE change in which one adult cell type (usually epithelial) is replaced by another adult cell type – can be physiological or pathological.
Examples of physiological, adaptive metaplasia? (x2)
Columnar epithelium of cervix changes to squamous when exposed to more acidic environments. Similarly, oesophagus – in acid reflux, changes from squamous to columnar – Barrett’s oesophagus.
What is the definition of dysplasia?
Abnormal pattern of growth where some of the cellular and architectural features of malignancy are present – INTACT BASEMENT MEMBRANE, hence non-invasive.
What are the features that describe dysplasia? (x4)
Loss of architectural orientation. Loss of uniformity of individual cells. Nucleus:cytoplasm ratio is enlarged – nuclei become hyperchromatic, so looks histologically DARKER. Mitotic figures – abundant, abnormal and in places not usually expected.
Where is dysplasia common? (x6)
• CERVIX – HPV infection. • BRONCHUS – Smoking. • COLON – Ulcerative colitis. • LARYNX – smoking. • STOMACH – pernicious anaemia. • OESOPHAGUS – acid reflux.
What are the two dysplasia classifications? Difference?
- LOW GRADE: low risk of progression and likely to be easily reversible.
- HIGH GRADE: likely to progress and less likely to spontaneously regress.
Relationship between metaplasia and dysplasia?
Metaplasia and dysplasia tend to occur together - and explain how can get cancers of wrong type of epithelium e.g. Squamous lung cell cancer.
What is neoplasia? Other names? (x2)
aka TUMOUR or MALIGNANCY. Describes an abnormal, autonomous proliferation of cells unresponsive to normal growth control mechanisms.
What are the differences between a malignant and benign tumour? (x6)
Look at photo.
In what circumstances may benign tumours be fatal? (x6)
• If there are in a dangerous place e.g. meninges or pituitary. • The tumour secretes something dangerous e.g. insulinoma. • Gets infected e.g. bladder. • Bleeds e.g. GI tract. • Ruptures e.g. liver adenoma. • Torts (twisted) e.g. ovarian cysts.
What is a metastasis? What factors determine this?
A discontinuous growing colony of tumour cells, at some distance from the primary cancer i.e. spread. These depend on the lymphatic and vascular drainage of the site of the primary tumour.
What is the nomenclature of benign epithelial tumours?
• PAPILLOMA: of the surface epithelium e.g. skin or bladder. • ADENOMA: of glandular epithelium e.g. stomach, thyroid, colon, kidney, pituitary, pancreas.
What is a carcinoma?
A malignant tumour derived from EPITHELIUM e.g. squamous cell carcinoma, adenocarcinoma, transitional cell carcinoma, basal cell carcinoma.
What is a benign soft tissue tumour?
Benign tumours of soft tissue. Soft tissue is of mesodermal origin – including, muscle, tendons, ligaments, fascia, fat. They are all connective tissues.
What is a sarcoma?
A malignant tumour derived from cells of mesenchymal origin – SOFT TISSUE, describing connective tissue cells. Sarcomas also include bones, although these are not ‘soft’.
What is the nomenclature of sarcomas? (x6)
• Liposarcoma – fat. • Osteosarcoma – bone. • Chondrosarcoma – cartilage. • Rhabdomyosarcoma – striated muscle. • Leiomyosarcoma – smooth muscle. • Malignant Peripheral Nerve Sheath Tumour – nerve sheath.
What is the difference between leukaemia and lymphoma?
• They are both cancers of the blood. • LEUKAEMIA: malignant tumour of bone marrow derived cells in circulating blood. • LYMPHOMA: malignant tumour of lymphocytes in lymph nodes.
What is teratoma? Sex difference?
Tumour derived from germ cells which have the potential to develop to tumours of all three germ cell layers – ectoderm, mesoderm AND endoderm. In males, all gonadal teratomas are MALIGNANT; in females, most gonadal teratomas are BENIGN.
What is hamartoma?
Localised overgrowth of cells/tissues native to the organ – cells are mature but architecturally abnormal. In other words, the cells look completely normal, but they way they’re arranged is abnormal.
