Pathology and classification of neoplasms Flashcards
What is a neoplasm?
An new and abnormal growth in tissue. It is a mass of cells that have undergone an irreversible change to proliferate in an uncoordinated manner independently to factors controlling normal growth.
What is cancer?
What is a tumour?
A malignant neoplasm
A tissue swelling
Does a neoplasm continue to grow?
Even if the initiating stimulus has been removed.
In which 4 ways can a neoplasm be classified?
Behavioural
Histogenesis
Histology
Functional
What does behaviour classify the neoplasm into?
Benign or malignant
What is a malignant neoplasm?
Locally invading and metastasising tissue that forms secondary deposits through lymphatics or blood.
How does an intermediate neoplasm behave?
It is locally invading but not metastasising. e.g. basal cell carcinoma of skin
Why is staging useful?
Describes the extent of spread and is important for prognosis and treament
What is the most common staging system?
TNM
T = Tumour size and local spread
N = Lymph node involvement
M = Metastasis
How does histogenesis classify?
Describes the tissue of origin and extent of differentiation.
What type of behaviour do mesenchymal neoplasms normally have?
Benign
What do haemato-lymphoid neoplasmas lead to?
Lymphoma and leukaemia
What do germ cell neoplasms lead to?
Teratoma or seminoma
What is differentiation?
The degree to which the neoplasms histologically resembles its tissue of origin.
What is the differentiation of a benign neoplasm?
Well differentiated and closely resembles tissue of origin
What is the differentiation of a malignant neoplasm?
Less differentiated and resembles origin less. The degree will vary.
What is the function of grading?
Describes the degree of differentiation and is useful for prognosis and treatment.
What is the normal grading system?
1 = well differentiated 2 = moderately differentiated 3 = poorly differentiated
What is an ANAPLASTIC neoplasm?
A malignant tumour that is too poorly differentiated to be able to determine its tissue of origin.
What name is given to a malignant epithelial tumour?
Carcinoma
Papilloma (benign)
Forms the suffix to the tumour name
What name is given to a malignant mesenchyme tumour?
Sarcoma
Forms the suffix to the tumour name
A neoplasm arising from glandular tissue is called..
Adenoma (benign)
Adenocarcinoma (malignant)
A neoplasm arising from cartilage is called..
Chondroma
Chondrsarcoma
A neoplasm arising from bone is called..
Osteoma
Osteosarcoma
A neoplasm arising from smooth muscles is called..
Leiomyoma
Leiomyosarcoma
What is histology classification?
Classifies tumours based on their histological appearance/features
What is a papillary feature?
Finger like structures - commonly spread via lymphatics
What is a follicular feature?
Forms glandular structures - commonly spreads haematogeneously to form bone metastases
Where do anaplastic tumours normal spread?
Locally invade and have poor survival
What is functional classification?
Classifies according to the substances it produces.
What do endocrine neoplasms produce?
Secrete functioning and active hormones
Where is an insulinoma located?
Insulin producing pancreatic islet cell
Where is a prolactinoma located?
Prolactin producing Anterior pituitary neoplasm
What is a teratoma?
A neoplasm derived from embryonic germ cells which have the capacity to form tissues from any of the 3 germ layers.
Where do teratomas commonly occur?
Ovaries (benign cysts), Testes (malignant) and midline structures such as mediastinum and retroperitoneum.
What is an embryonic tumour?
A neoplasm occurring in a developing organ, derived from multi-potent embryonic blast cells.
What is the name given to an embryonic tumour?
suffix = Blastoma
When do blastomas usually present?
Present at or soon after birth
Respond well to aggressive treatment
Usually have different differentiations within
What is a hamartoma?
A tumour like malformation that presents at birth but stops growing as the host stops. e.g. pigmented skin naevi, skin haemangiomas.
What is the gross appearance of a malignant tumour?
Irregular shape, large with ulceration, haemorrhage and necrosis
What is the gross appearance of a benign tumour?
Well defined and circumscribed, usually smaller with no haemorrhage, ulceration or necrosis
What is a key difference between malignant and benign?
Malignant invade and metastasise, benign do not.
What is the microscopic appearance of a malignant tumour?
Enlarged nucleus with prominent nucleoli
Pleomorphism present (varying cell shape and size)
Frequent and atypical mitotsis in cells
Variable differentation
What is the microscopic appearance of a benign tumour?
Normal nucleus with small nucleoli
Absence of pleomorphism
Infrequent mitosis
Well differentiated
What is the difference between the growth of a benign and malignant tumour?
Benign grow slowly and spontaneously arrest.
Malignant grow rapid without arrest
What are the main effects of a benign tumour on the host?
It creates mechanical pressure
What are the main effects of a malignant tumour?
Causes mechanical pressure Invasion damages vital structures Metastasis - common cause of death Development of paraneoplastic syndromes Death is frequent
What is a paraneoplastic syndrome?
A rare disorder that is triggered by an altered immune system in response to a neoplasm. They are nonmetastatic systemic effects that are not related to the location of the tumour. e.g. SIADH, Cushing’s
