Using the pathologist in diagnosis and grading tumours Flashcards
What are the gross characteristics of benign tumours?
growth by expansion
low to moderate growth rate
tumour well-demarcated from surrounding tissue which it is compressing
often smooth in gross outline
has a surrounding connective tissue capsule
usually freely mobile on palpation
homogeneous cut surface (may be cystic in glandular tumours)
generally little haemorrhage or necrosis
surgical removal often easy
no recurrence if completly excised
no metastasis spread elsewhere in the body!!!
What are the microscopic characteristics of benign tumours?
often very similar to the tissue of origin
tissue well organised
benign endocrine tumours can be functional producing hormones affecting other parts of body
surrounding connective tissue capsule
tumour does not broach this capsule
few or no mitoses
generally no hameorrhage or necrosis
What are the gross characteristics of malignant tumours?
growth by invasion of adjacent tissue
usually not encapsulated
usually not mobile on palpation
complete removal often difficult/impossible
often recurs after excision
often ulcerate if on skin or mucosal surface
frequently show internal necrosis and haemorrhage
can metastasize to local LN and lungs
What are the microscopic characteristics of malignant tumours?
variable cell size/shape: anisocytosis/pleomorphism
variable nuclei size/shape: anisokaryosis
increased nuclear to cytoplasmic ratio
prominent nucleoli
presence of normal or abnormal mitoses
loss of cohesiveness/structure
malignant fusion leading to the formation of multinucleated cells
secondary changes: necrosis, fibrosis or inflammation
usually unencapsulated
What is the nomenclature for a benign surface epithelial tumour?
tissue of origin + papilloma
viral induced
What is the nomenclature for a benign glandular epithelial tumour?
tissue of origin + adenoma
What is the nomenclature for a malignant epithelial tumour?
tissue of origin + carcinoma
What is the nomenclature for a malignant glandular epithelial tumour?
tissue of origin + adenocarcinoma
What is the nomenclature for benign mesenchymal tumours?
tissue of origin -oma
What is the nomenclature for malignant mesenchymal tumours?
tissue of origin -sarcoma
What is the nomenclature for fibrous tissue of origin?
fibro
What is the nomenclature for bone tissue of origin?
osteo
What is the nomenclature for cartilage tissue of origin?
chrondro
What is the nomenclature for adipose tissue of origin?
lipo
What is the nomenclature for smooth muscle tissue of origin?
leiomyo
What is the nomenclature for endothelium tissue of origin?
haemangio
What is the nomenclature for skeletal muscle tissue of origin?
Rhabdomyo
What is a lymphoma?
tumour of lymphoid system, usually malignant
What is a melanoma?
tumour of melanocyted
benign or malignant
What are mast cell tumours?
tumour of mast cell
vary in degree of malignancy
What are leukaemias?
tumours derived from cells of bone marrow which circulate in the blood
What are teratomas?
germ cell tumours with elements of ectoderm, endoderm, mesoderm
What are sarcoids?
low grade fibrosarcomas commonly see in skin of horses
caused by bovine papillomavirus infection
Which tumours are likely to cause lymphatic metastasis?
carcinoma
LN draining tumour
Which tumours are likely to cause vascular metastasis?
sarcoma
tumour “seeds” widely to internal organs
Which tumours are likely to cause trans-cavity/coelomic metastasis?
mesothelioma or ovarian carcinomas
tumour spreads across serosal surfaces
What are multicentric tumours?
tumours where its difficult to determine a primary site due to multiple tumours present at first presentation
ex: lymphoma
What is cytokeratin?
immunohistochemistry epithelial marker for carcinoma
What is vimentin?
immunochemistry mesenchymal marker for sarcoma
What is CD3?
immunohistochemistry t cell marker for t cell lymphoma
Wat is CD79a/CD20?
immunohistochemistry b cell markers for b cell lymphoma
What are common ways of tumour grading?
grading on light microscopy
immunophenotyping
detection of genetic mutations
use of proliferation markers
