Flashcards in MoD Neoplasia 1 Deck (21):
An abnormal growth of cells that persists after the initial stimulus is removed
For malignant neoplasms: AND invades surrounding tissue with the potential to spread to distant sites
A clinically detectable lump or swelling
Any malignant neoplasm
A malignant neoplasm that has spread from its primary site to a non-contiguous secondary site
A pre-neoplastic alteration in which cells show disordered tissue organisation. (It is not neoplastic because its reversible)
Whats the difference between benign and malignant tumours?
Benign neoplasms are confined to their site of origin whereas malignant neoplasms have the potential to metastasise.
How do benign and malignant neoplasms differ macroscopically?
Benign neoplasms grow in a confined area so have a pushing outer margin, they feel round and mobile.
Malignant neoplasms have an irregular margin and may show areas of necrosis (grow faster than the blood supply) and ulceration (break in the epithelium), so they feel bumpy and immobile.
Cells are poorly differentiated and have no resemblance to any tissue type
How to benign and malignant neoplasms differ microscopically? and how is this related to their grading?
Benign neoplasms have cells that are well differentiated so closely resemble the parent tissue.
Malignant neoplasms range from well to poorly differentiated.
Grade 1 - well differentiated, high survival rate
Grade 2 - moderately differentiated, moderate survival
Grade 3 - poorly differentiated, low survival rate
How to cells appear microscopically with worsening differentiation?
Increased nuclear size and nuclear to cytoplasmic ratio
Increased nucleus staining (HYPERCHROMASIA)
More mitotic figures
Increased variation in size and shape of cells and nuclei (PLEOMORPHISM)
Whats the difference between invasive and in-situ malignancy?
Carcinoma in-situ does not invade the basement membrane whereas invasive carcinoma does. Invasive has a poorer prognosis
Discuss the clonality of neoplasms, and how we know they are monoclonal
Cells are monoclonal if they all originate from a single cell. We know that neoplasms are malignant through study of the X linked gene for glucose-6 phosphate dehydrogenase (G6PD) in tumour tissue. The gene has several alleles.
In female embryogenesis one allele is randomly inactivated in each cell (LYONISATION). In heterozygous women normal tissues will be a patchwork of the two different alleles whereas neoplastic tissues only express the one allele.
What are photo-oncogenes?
Porto-Oncogenes are normal genes that can become abnormally activated to form oncogenes that favour neoplasm formation.
Oncogenes inactive tumour supressor genes.
What causes neoplasia?
Accumulated mutations in somatic cells.
The mutations are called initiators (mutagenic agents) and promotors cause cell proliferation.
Initiators need lots of promotion to cause cancer.
Main initiators are chemicals, infections and radiation. Mutations can also be inherited (may result in neoplasm at a young age).
An accumulation of mutations in a monoclonal cell population
What are the endings for the different types of neoplasms?
Benign neoplasms end in -oma
Malignant neoplasms end in -carcinoma if they are epithelial (90%) or -sarcoma if they are stromal
Describe the different names of benign epithelial neoplasms
Benign stratified squamous neoplasms are called squamous papilloma's (polyps with finger like projections)
Benign transitional neoplasms are called transitional cell papillomas
Benign glandular neoplasms are called adenomas
Describe the different names of malignant epithelial neoplasms
Malignant epithelial neoplasms are called carcinomas
Malignant glandular neoplasms are called adenocarcinomas
How are lymphoid and haematopoietic cancers named?
ALL regarded as malignant
Neoplasms of lymphoid tissue are called lymphomas
Haematopoietic cancers and calles leukaemias
How are germ cell neoplasms named?
Benign teratoma (also called dermoid cyst)