L1: Cancer pathology Flashcards
tumour microenvironment
Tumour microenvironment: fibroblasts, tumour cells, stromal cells etc. One of the hallmarks of cancer cells. Microbiome is also another hallmark.
neoplasm (willis)
Neoplasm (Willis): abnormal mass of tissue, the growth of which exceeds + is uncoordinated with normal tissue growth. Persists in the same excessive manner after cessation of the stimuli which evoked the change.
basic tumour components
Basic tumour components:
Proliferating neoplastic cells that constitute the parenchyma
Supportive stroma made up of connective tissue, blood vessels and possibly lymphatics
Image of bowel: mucle layer (sclerosa)= outside of bowel
mucinous cystadenoma of the ovary
Mucinous Cystadenoma of the Ovary – Clarified Notes
Mucinous = The tumour is made of mucin-producing epithelial cells. Mucin is a gel-like substance, and the presence of mucin indicates that the tumour cells are still functionally active, though not necessarily that they are dividing more (just that they’re producing mucin).
Cystadenoma =
Cyst: Fluid-filled structure
Adenoma: A benign tumour of glandular origin
So, a cystadenoma is a benign tumour that forms cysts and originates from glandular tissue.
Benign = Non-cancerous. It does not invade surrounding tissues or metastasize.
Ovarian tumours:
Can grow very large, sometimes filling the entire abdominal cavity.
May be bilateral (affecting both ovaries), although mucinous tumours are more commonly unilateral, while serous tumours are often bilateral.
dermoid cyst?
Dermoid Cyst (Mature Cystic Teratoma)
Origin:
Arises from pluripotent germ cells that can differentiate into all three embryonic germ layers:
Ectoderm (e.g., skin, hair, teeth)
Mesoderm (e.g., muscle, bone, cartilage)
Endoderm (e.g., respiratory and gastrointestinal epithelium)
Contents:
These cysts can contain a variety of tissues such as:
Hair
Sebaceous material (oily)
Teeth
Bone
Cartilage
This variety is due to the differentiation from all three layers.
Location:
Most commonly found in the ovaries in women.
The equivalent in men (testes) is called a teratoma.
“Dermoid cyst” is often used synonymously with mature cystic teratoma in the ovary.
Benign or malignant?
Usually benign, especially in young women.
Rarely, they can undergo malignant transformation (e.g., into squamous cell carcinoma).
Clinical facts:
Common in women of reproductive age.
Can be unilateral or bilateral, though more often unilateral.
Can grow large but often asymptomatic unless they twist (causing ovarian torsion) or rupture.
malignant tumour nomenclature?
- By Tissue of Origin:
Carcinomas:
Malignant tumours of epithelial origin (arising from ectoderm, mesoderm, or endoderm).
Examples:
Adenocarcinoma (from glandular epithelium)
Squamous cell carcinoma (from squamous epithelium)
Sarcomas:
Malignant tumours of mesenchymal origin (connective tissues like bone, muscle, fat, blood vessels).
Examples:
Osteosarcoma (bone)
Liposarcoma (fat)
Leiomyosarcoma (smooth muscle)
Epithelial Tumour Progression
Squamous Carcinoma In Situ
“In situ” = has not invaded the underlying basement membrane.
Still confined to the epithelium.
Basement membrane is rich in type IV collagen and separates epithelial cells from connective tissue.
Invasive Squamous Cell Carcinoma
Once tumour breaks through the basement membrane, it’s classified as invasive.
Invasive SCC can:
Metastasise
Ulcerate
Cause disfigurement
Urgent treatment is needed: diagnosis should be followed by treatment within 2–3 weeks.
Basal Cell Carcinoma (BCC)
Most common skin cancer.
Arises from basal layer of the epidermis.
Appears blue-purple on H&E stain due to basophilic nuclei.
gastric adenocarcinoma?
Gastric Adenocarcinoma (Stomach Cancer)
Histological Appearance:
The dark bits = nuclei
The clear areas in the cytoplasm = mucin
Mucin pushes the nucleus to the periphery, giving the cell a signet ring appearance.
Signet Ring Cell Carcinoma:
A type of gastric adenocarcinoma
Characterised by:
Mucin-filled cells with peripheral nuclei
Common in diffuse-type gastric cancer
These cells infiltrate the stomach wall diffusely, not forming a clear mass
Linitis Plastica:
A condition caused by diffuse infiltration of the stomach wall by cancer cells (often signet ring type)
Leads to:
Thickened, rigid stomach wall
Loss of distensibility → stomach cannot expand properly
Patients feel very full quickly after eating (early satiety)
mechanisms of cancer invasion?
Mechanisms of cancer invasion
Physical invasion
Reduced adhesiveness and cohesiveness of tumour cells- example: in petri dish in agar, if tried to groe (benign) fibroblasts in culture, once grown in a single-layer they will stop growing. In cancer cells, continue to grow on top of eachother, some will break off, that have acquired new mutations and able to break through the colony? And digest their way through the collagen will move along and start looking for blood vessels and lymphatics.
Increased motility of tumour cells
Loss of “contact inhibition”
Release of destructive enzymes
differences between benign and malignant neoplasms?
Differences between benign and malignant neoplasms
Differentiation and anaplasia
Rate of growth
Encapsulation – invasion - benign often not always encapsulated. Capsule contains them. E.g: benign tumours of ovaries e.g: fibroids. Often ‘scooped’ out of the uterus (shelled out). Lipomas not encapsulated- benign tumours of fat that can be shelled out? Very easily.
Metastasis
Benign- grow very slowly, generally will not kill you, sometimes stop growing for years. Generally as example: benign tumour of brain minengioma? (tumour of lining of brain) that can kill you as they can be in sites neurosurgeons cannot operate and expand. Brain- once become adult, all our sultures? Fuse so will not expand. Something growing will increase intracranial pressure and so person can die but generally will not/virtually never
differentiation and anaplasia?
Apply to the parenchymal cells of the neoplasm.
Differentiation refers to the extent to which the parenchymal cells resemble comparable normal cells, both morphologically and functionally.
In general, all benign tumours are well differentiated.
Malignant tumours range from well differentiated to undifferentiated.
Anaplasia means “to form backward”.
Differentiation : in simple terms, how much a cancer cell resembles the tissue it has arisen from. More differentiated= more it resembles tissue it has come from. E,g: tumour of skin. Look at tumour cells and the adjacent keratonocutes- normal cells of the skin. If readily recognise the tumour cell is or has been derived from kertatonocyte then well differentiated. In general benign tumours are well differentiated. Malignant- moderate or poorly differentiated.
Anaplasia- essentially the very end of poor differentiation. Very poorly differentiated.
