Tumour Pathology Flashcards
Classification of tumours
Benign vs malignant. Based on the tissue of origin; epithelium, connective (mesenchyme), blood, lymphoid, melanocytes, neural or germ cells.
Nomenclature of tumours
Tissue/location(type)/benign/malignant epithelium/glandular/adenoma/adeno-carcinoma epithelium/squamous/papilloma/carcinoma connnective/bone/osteoma/osteo-sarcoma connective/fat/lipoma/lipo-sarcoma Fibrous/tendons, ligaments/fibroma/fibro-sarcoma blood/WBCs/none/leukaemia lymphoid/blank/none/lymphoma melanocyte/skin/naevus/melanoma nervous/CNS/none/astrocytoma nervous/PNS/schwannoma/none germ cells/ovary/teratoma/none germ cells/testis/none/teratoma
Cancer
The ability to invade adjacent tissue and to metastasis and grow at other sites within the body.
Tumour growth
The growth of a tumour is uncoordinated with that of surrounding normal tissue. Its growth continues after the removal of any stimulus and it is an irreversible change.
Benign tumours
Growth pattern; non-invasive Presence of capsule; usually encapsulated invasion; non evidence Presence of mets; none differentiation; well differentiated appearance of cells; similar to normal function of tissue; similar to normal behaviour; rarely cause death
Malignant tumours
Growth pattern; invasive Capsule; no/breached capsule invasion; potential mets;often differentiation; poorly differentiated appearance of cells; abnormal function of tissue; loss of function behaviour; frequently cause death
Properties of cancer cells
- Loss of tumour suppressor genes
- Gain of function of oncogenes
- Altered cellular function; loss of cell adhesion, altered cell-matrix adhesion, production of tumour related properties.
- Abnormal morphology
- Cells capable of independent growth
- Tumour biomarkers
Angiogenesis
New blood vessel formation by tumours which are required to sustain tumour growth. However, provides a route for release of tumour cells into circulation. More vessels equals a poorer prognosis
Apoptosis
The death of cells which occurs as a normal and controlled part of an organism’s growth or development. Active cell process which regulates tumour growth, Involved in response to chemo and radiotherapy.
Modes of spread of cancer
- Local spread; invasion into adjacent connective tissue and lymph/blood vessels.
- Lymphatic spread; adherence of tumour cells to lymph vessels, invasion from lymphatics into lymph nodes.
- Blood; adherence of tumour cells to blood vessels, invasion from vessels into tissue.
- Trans-coelomic spread; a special form of local spread across body cavities e.g. pleural/peritoneal. Common in lung, stomach, colon and ovary cancers.
Metastasis
Invasion and metastasis is a multi-step process involving increased matrix degradation by proteolytic enzymes resulting in altered cell-cell and cell-matrix adhesion. Sites of mets are not related to tissue blood flow and depends on both tumour and tissue related factors. Common sites; liver, lung, brain, bone, adrenal gland, omentum.
Local effects of cancer
Benign; pressure, obstrcution
Malignant; pressure, obstruction, tissue destruction (ulceration, infection), bleeding (anaemia, haemorrhage), pain (pressure on nerves, perineural, infiltration, pathological fractures), effects of treatment.
Systemic effects of cancer
Malignant; weight loss (cancer cachexia), secretion of hormones (normal and abnormal/inappropriate), paraneoplastic syndromes, effects of treatment.
Early detection of cancer
Important to detect cancer at an early stage to reduce/prevent morbidity/mortality. Detection at a pre-invasive stage allows for identification of dysplasia/intra-epithelial neoplasia. This requires an effective test which is sensitive, specific and acceptable e.g. cervical cancer screening.
Dysplasia
Earliest pre-malignant change that can be visualised. Identified in epithelium with no invasion but can progress to cancer. Features; disorganisation of cells (increased nuclear size/mitosis) and may be graded high or low.
