Using The Pathologist Flashcards
Define Neoplasia (Three key points)
An uncontrollable proliferation of cells
Proliferation continues in the absence of inciting cause
Neoplastic cells originate from a single cell which has undergone mutation and lost the ability to control its division
Which patients are particularly prone to developing squamous cell carcinomas?
Why?
Where are they usually found?
White cats
Lack melanin in the skin
Nasal planum and ear tips
How do benign tumours grow?
Expansion
Describe the growth rate of benign tumours
Low to moderate
Describe the gross appearance of a benign tumour in relation to the surrounding tissue
Well-demarcated from surrounding tissue
Smooth outline
What usually surrounds a benign tumour?
Connective tissue capsule
How do benign tumours usually feel on palpation?
Freely movable
Describe the cut surface of a benign tumour
Homogeneous
May be cystic in glandular tissues
(Generally little haemorrhage or necrosis)
How easy/successful is surgical removal of benign tumours?
Often easy (dependent on location)
No recurrence if completely excised
What is a key feature of benign tumours?
No metastasis to elsewhere in the body
Describe the microscopic features of benign tumours
Often very similar to the tissue of origin
Tissue well organised
Endocrine tumours can be functional
Surrounding connective tissue capsule that tumour doesn’t broach
Few/no mitoses
Generally no haemorrhage or necrosis
Describe the growth of malignant tumours
Growth by invasion into adjacent tissue
Are malignant tumours usually encapsulated?
No
Describe how malignant tumours feel on palpation
Describe their usual gross appearance if on skin/mucosa
Usually not mobile
Often ulcerate if on skin or mucosal surface
How easy/successful are surgical attempts to remove malignant tumours?
Complete removal often difficult
Often recurs after excision
Describe the internal appearance of a malignant tumour
Frequently show internal necrosis or haemorrhage
Can malignant tumours metastasise?
If so, where?
Yes - some more readily than others
First to local lymph nodes, lungs
Describe the microscopic features of malignant tumours.
—Variable cell size and shape - anisocytosis / pleomorphism
— Anisokaryosis
—increased nuclear:cytoplasm
—prominent nucleoli
— presence of mitoses
— loss of cohesiveness and structure
— malignant fusion -> multinucleated cells
— secondary changes -> necrosis, fibrosis, inflammation
— usually unencapsulated - if presence, often invaded
What do you term a benign tumour of the surface epithelia (e.g. skin)?
Papilloma
What do you term a benign tumour of the glandular epithelia?
Adenoma
What is used as a prefix for benign tumours of epithelial origin?
Tissue of origin e.g. squamous, thyroid
What do you term a malignant tumour of epithelial origin?
Carcinoma
What do you term a malignant tumour of the glandular epithelium?
Adenocarcinoma
Where is the tissue of origin stated for malignant tumours of epithelial origin?
Added at the beginning e.g. squamous cell carcinoma, mammary adenocarcinoma
What is the basic rule when naming malignant and benign tumours of mesenchymal origin?
Benign - add -Oma to the tissue of origin
Malignant - add -sarcoma to the tissue of origin
Give the names for benign and malignant tumours of fibrous tissue origin
Fibroma
Fibrosarcoma
Give the names for benign and malignant tumours of bone tissue origin
Osteoma
Osteosarcoma
Give the names for benign and malignant tumours of cartilage tissue origin
Chondroma
Chondrosarcoma
Give the names for benign and malignant tumours of adipose tissue origin
Lipoma
Liposarcoma
Give the names for benign and malignant tumours of smooth muscle tissue origin
Leiomyoma
Leiomyosarcoma
Give the names for benign and malignant tumours of endothelial tissue origin
Haemangioma
Haemangiosarcoma
Give the names for benign and malignant tumours of skeletal muscle tissue origin
Rhabdomyoma
Rhabdomyosarcoma
What is a granuloma?
NOT a neoplasm
Organised type of chronic inflammation
What is a lymphoma?
Are they usually benign or malignant?
Tumours of the lymphoid system
Usually malignant
What is a Melanoma ?
Are they usually benign or malignant?
Tumour of melanocytes
Some benign others malignant
(‘Malignant melanoma ‘).
What is a mast cell tumour?
Are they usually benign or malignant?
Tumour of mast cells (mastocytoma)
Vary in degrees of malignancy
What is leukaemia?
Are they usually benign or malignant?
Tumours derived from cells of the bone marrow which circulate in the blood
What is a teratoma?
Are they usually benign or malignant?
Germ cell tumours with elements of ectoderm, endoderm and mesoderm
What are sarcoids?
What causes them?
Low grade fibrosarcoma commonly seen in the skin of horses
BPV
What are the four routes of tumour metastasis?
Lymphatic
Vascular
Trans-coelomic
Local
What tumours commonly use lymphatic spread for metastasis?
What do you expect to find in lymph nodes?
Carcinomas
Draining lymph nodes contain secondary metastases
Which tumour type tends to favour vascular metastasis?
Where would you expect to find secondary tumours?
Sarcoma
Seeds widely to internal organs e.g. liver and lungs
Which tumour type tends to favour trans-coelomic metastasis?
Where do you find secondary tumours?
Mesothelioma or ovarian carcinoma
Tumour spreads across serosal surfaces (may be associated with effusion)
Where would you expect to find secondary tumours when local metastasis occurs?
Spread along fascial planes
What are multicentric tumours?
Multiple tumours present on first presentation
— difficult to determine a primary site as multiple tumours present at first presentation
