- uncontrolled cell proliferation - proliferation continues in absence of inciting cause - neoplastic cells originate from single cell which has lost ability to control its division

Using the pathologist Flashcards by Emily Stacey

Define neoplasia 3

uncontrolled cell proliferation
proliferation continues in absence of inciting cause
neoplastic cells originate from single cell which has lost ability to control its division

How well did you know this?

Not at all

Perfectly

What is tumour classification based on?

clinical and pathological features

How well did you know this?

Not at all

Perfectly

What are gross features of benign tumours

growth by expansion
low to moderate growth rate
tumour well demarcated (compresses surrounding tissue)
smooth in gross outline
surrounding CT capsule
freely mobile on palpation
homogenous cut surface (cystic in glandular tissue)
little haemorrhage or necrosis
surgical removal often easy
no recurrence if completely excised
no metastasis

How well did you know this?

Not at all

Perfectly

What are microscopic features of benign tumours?

very similar to tissue of origin
well organised
benign endocrine tumours can be functional
surrounding CT capsule - tumour doesn’t broach this
few or no mitoses
generally no haemorrhage or necrosis

How well did you know this?

Not at all

Perfectly

Gross features - malignant tumours

growth by invasion
not encapsulated
not usually mobile on palpation
complete removal often difficult
often recurs after excision
often ulcerate if on skin or mucosal surface
secondary changes - internal necrosis and haemorrhage
can metastasise to local LNs and lungs (often)

How well did you know this?

Not at all

Perfectly

Microscopic features - malignant tumours

pleomorphism
anisokaryosis
increased nuclear: cytoplasmic ratio
prominent nucleoli
normal/abnormall mitoses
loss of cohesiveness and structure
syncytia
secondary changes - necrosis, fibrosis, inflammation
usually not encapsulated

How well did you know this?

Not at all

Perfectly

Define anisokaryosis

variable size and shape of nucleoli

How well did you know this?

Not at all

Perfectly

Define pleomorphism

variable cell size and shape

How well did you know this?

Not at all

Perfectly

Define papilloma

benign, surface epithelia

How well did you know this?

Not at all

Perfectly

Define adenoma

Benign tumour, glandular epithelia

How well did you know this?

Not at all

Perfectly

Define thyroid adenoma

glandular epithelia (benign) tumour prefixed by the tissue of origin

How well did you know this?

Not at all

Perfectly

Define carcinoma

malignant, epithelial origin

How well did you know this?

Not at all

Perfectly

Define adenocarcinoma

malignant tumour of glandular epithelia

How well did you know this?

Not at all

Perfectly

Is a tumour ending in -oma benign or malignant?

Benign (except granuloma - chronic inflammation). Tumours with the ending -sarcoma are malignant

How well did you know this?

Not at all

Perfectly

Define lymphoma

tumours of lymphoid system

usually malignant

How well did you know this?

Not at all

Perfectly

Define melanoma

Tumour of melanocytes

some benign, other malignant (malignant melanomas)

How well did you know this?

Not at all

Perfectly

Define MCT (mastocytoma)

tumour of mast cells

vary in degree of malignancy

Define leukaemia

tumours derived from cells of BM which then circulate in the blood

Define teratoma

germ cell tumours with elements of ectoderm, endoderm and mesoderm

Define sarcoid. Cause?

low grade fibrosarcoma

commonly seen in the skin of horses (caused by BPV)

How can tumours metastasise? 4

lymphatic
vascular
trans-cavity
local

What is lymphatic spread typical of?

Carcinomas

Tumour spreads across serosal surfaces (may be associated with effusions)

Outline vascular spread

Typical of sarcoma

Tumour seeds widely to internal organs (liver and lungs)

Outline trans-cavity spread

Typical of mesothelioma
Less common
Spreads across serosal surfaces

Outline local metastasis

May occur in multiple tumour types Less common Spread along fascial planes

Define multicentric tumour

where it is difficult to determine a primary site as multiple tumours are present at first presentation

List some malignant tumours that metastasise rapidly and constantly

``` tonsillar carcinomas pancreatic carcinomas OSA oral and digital melanomas mammary carcinomas (cats) ```

List some malignant tumours that metastasise slowly or rarely

``` SCC = tend to invade extensively before undergoing metastasis Fibrosarcomas = tend to invade and therefore recur at the site of excision, without undergoing metastasis ```

List 4 examples of IHC markers and their uses | epithelial, mesenchymal, TC and BC markers

Cytokeratin - epithelial marker - carcinoma Vimentin - mesenchymal marker - sarcoma CD3 - TC marker - TC lymphoma CD79a - BC marker - BC lymphoma

What is tumour grading?

measure of differentiation

How can tumours be graded? 4

Light microscopy (SCC - keratin production) Immunophenotyping (lymphoma) Detection of genetic mutations (lymphoma) Use of proliferation markers (MCTs)

What is cytogenetics?

A method of tumour grading where the specific mutation is detected - this is the standard practice for human lymphomas.

What is Ki-67?

A proliferation marker that can be detected for tumour grading. Particularly useful for MCT grading in dogs.

Define clinical audit

to determine why a therapy might have failed

How can a pathologist help a clinician

``` Obtain definitive Dx or shortlist Prognosis estimate Treatment plan Client education Clinical audit ```

What should a biopsy report contain? 5

Signalment and clinical history Gross description Clear and concise histological description Diagnosis or likely DDx Comments on biological behaviour and prognosis with recommendations for monitoring/treatment and client education.

When should you call the path lab? 4

If path diagnosis doesn't fit with clinical findings Before tissue collection in unusual cases Urgent results needed Follow-up appreciated

What does the pathologist require?

Representative sample Correctly submitted Full clinical history

How can a sample be taken?

Incisional - punch, trucut, endoscopic or wedge# OR Excisional Include margin of normal tissue Avoid necrotic and cavitated areas (usually central, except bone tumours where area of max lysis is useful) Mark margins of interest (suture tag or indelible dye) Identify samples from different sites [Imaging guidance]

How do you submit a sample?

Large volume of neutral buffered formalin (4:1 or 10:1) <2cm in longest dimension Larger specimens unfixed if close to lab Royal Mail guidelines for path. specimens Label - indelible, practice, owner, animal, site, difference between sites, normal and abnormal sites (esp skin biopsies)

What should be included on the full clinical history?

``` Signalment Clinical History Previous lab results previous therapy Clinical Dx or DDx Special considerations (forensic, legal) Gross description/photo ```