2 - Neoplasia Flashcards
Neoplasm
An abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of normal tissues, and persists in the same excessive manner after apparent cessation of the stimuli which evoked the change
What does neoplasia exclude
- Hyperplasia
- Hypertrophy
- Inflammation
Two basic components of neoplasm
- Clonal cells from one type of progenitor (range from mature to immature primitive cells)
- Reactive stroma made up of connective tissue, blood vessels, and inflammatory cells
Classification of tumours
- Histogenetic (morphology, molecular)
- Aetiological
- Therapeutic biomarkers
Benign
Will remain localised (e.g. naevus)
Malignant
Invasion (locally or spread)
Molecular subtype of colorectal cancer with highest mutation count
CMS1
Classification by histogenesis
- Epithelium
- Mesenchyme (stroma/connective tissue elements)
- Blood and related cells
- Special cells (melanocytes, germ cells)
Tissue type of origin + “oma”
- Benign
- e.g. Lipoma
Cell/tissue type + “Carcinoma”
- Malignant
- E.g. adenocarcinoma (adeno: relating to glands)
Cell/tissue type + “Sarcoma”
- Malignant
- E.g. liposarcoma (adipocyte-like cells)
Examples of sarcomas
- Osteosarcoma (background mineralised bone)
- Leiomyosarcoma (smooth muscle fibres)
Differentiation
The extent to which neoplastic parenchymal cells resemble the corresponding normal parenchymal cells, both morphologically and functionally
Anaplasia
Lack of differentiation
Morphologic changes associated with anaplasia
- Variation in size and shape
- Atypical mitotic figures, sometimes producing tripolar or multipolar spindles (reflects higher proliferative activity of parenchymal cells)
- Loss of polarity (anaplastic cells grow in disorganised fashion)
- Abnormal cellular morphology