Tumour Classification Flashcards
What suffix do most tumours share?
Which characteristics determine how they are named?
most have the suffix “oma”
they are classified by histological origin, whether they are benign or malignant and whether they are primary or secondary
Why is naming tumours important?
- it characterises the lesion’s behaviour
- it determines prognosis
- it outlines treatment options
What are the 2 basic tissue types involved in histological classification?
epithelium:
this is tissue that lines surfaces
mesenchymal tissue:
- connective tissue (bones, ligaments, tendons, fat, cartilage)
- muscle
- nervous tissue
- marrow (haematological malignancies arise from different components that make up the blood cells)
What are the 2 types of benign epithelial tumours?
papillomas or adenomas
this depends on whether the epithelium is either glandular/secretory or not
What is an adenoma?
a benign epithelial tumour of glandular/secretory epithelium
What is a papilloma?
a benign epithelial tumour or non-secretory/non-glandular epithelium
How are papillomas classifed further?
by the cell type of origin
e.g. squamous cell papilloma, urothelial cell papilloma
How are adenomas further classified?
by the glandular tissue of origin
e.g. colonic adenoma, thyroid adenoma
What is the name for a malignant epithelial tumour?
carcinoma
What is an adenocarcinoma?
a malignant epithelial tumour of glandular epithelium
they can arise from any glandular epithelium, but the organ needs to be specified
e.g. lung adenocarcinoma, colorectal adenocarcinoma
How are carcinomas of non-glandular epithelium named?
based on the cell type that they have originated from
e.g. basal cell carcinoma, urothelial cell carcinoma
What is meant by a carcinoma “in-situ”?
the carcinoma has not yet invaded through the basement membrane
invasion is preceded by dysplasia (disordered maturation and nuclear changes)
if no action is taken, the carcinoma will invade
What are the following prefixes for benign mesencymal tumours?
the suffix is “oma”
e.g. tumour of bone would be osteoma
What are the prefixes and suffix for malignant mesenchymal tumours?
the suffix is ‘sarcoma’
e.g. a malignant tumour of adipose tissue would be liposarcoma
What are leiomyomas more commonly known as?
fibroids in the uterus
they are benign tumours of smooth muscle
What is the proper name for a mole?
melanocytic naevus
it is a benign melanocytic lesion that has many sub-types
What is a malignant melanoma?
it can be in-situ or invasive
it looks like a mole but is darker in colour and has a varying texture
What is a mesothelioma?
a tumour of the pleura covering the lungs
it is always invasive (no benign counterpart) and nearly always fatal
What are the 3 main types of CNS tumours?
- tumours of the meninges (lining of the brain) - meningioma
- tumours of glial cells - glioma
- ptiuitary tumours
How do neurones in the CNS form tumours?
neurones in the CNS rarely form tumours
tumours in the brain form from the glial cells (supportive cells)
In the PNS, neurones can form tumours
How often do tumours metastasize to the brain?
may tumours metastasize to the brain but generally not vice versa
this is due to the blood-brain barrier
Where are germ cells found?
germ cells make up the gonads (ovary and testis)
they are also found in the midline as primordial germ cells originate in the midline and then migrate to the gonads
What are the 2 main types of germ cell tumours?
seminoma - originates from sperm cells in the testes
dysgerminoma - originates from oocytes
How can a germ cell tumour be named based on differentiation?
- yolk sac tumour
- teratoma
- choriocarcinoma (placental tumour)
- embryonal carcinoma
- mixed germ cell tumour
What is significant about a teratoma?
it can differentiate into proper tissue types
there are often whole teeth or hairs within the tumour
there are many different tissue types found within the tumour
What are blastomas?
What do they look like?
blastomas are paediatric (embryonal) tumours
they look like embryonal cells so are called small round blue cell tumours
Why is it difficult to diagnose embryonal tumours just by looking at morphology?
tumours in children tend to look very similar and arise in similar locations
they all look like small round blue cells that form rosettes
genetic testing must be carried out to confirm diagnosis
What are the 3 types of haematological malignancies and the cells that are involved?
leukaemias:
- originate from bone marrow or blood
- involves overgrowth of a certain type of white blood cell
lymphoma:
- overgrowth of lymphocytes within lymph nodes
- generally divided into Hodgkin’s and non-Hodgkin’s
myeloma:
tumour of plasma cells
What is a harmartoma?
a benign tumour-like lesion
it is not neoplastic, it is just an overgrowth of tissue
wherever the tumour orignates from, they include a disorganised mixture of tissue types from that organ
When can a hamartoma cause a problem?
if it starts to compress something
What is a cyst?
a fluid-filled space lined by epithelium
this can be neoplastic and malignant, but is usually benign
What is the difference between a primary and a secondary tumour?
primary:
this is where the tumour is located at the site of origin
secondary:
this is where the tumour is metastatic and has travelled to implant itself in a new location
What happens if there is a case of an unknown primary tumour?
a tumour may be aggressive and malignant then the cells may not look like any particular type
immunohistochemistry is done to see which proteins are being expressed by the cells
name the benign epithelial tumours
name the malignant epithelial tumours
name the benign mesenchymal tumours
name the malignant mesenchymal tumours
