Pathology in diagnosis and management Flashcards
Why is tumour pathology important?
Useful for clinical presentation, classifying neoplasms and determining treatment options.
What are the main gross characteristics of a benign tumour?
Well circumscribed
Smooth
Mobile
What the main gross characteristics of a malignant tumour?
Irregular
Poorly defined
Fixed to adjacent tissue
What are the two types of breast lumps that can develop?
Fibroadenoma - benign glandular neoplasm in women <30. ‘Breast mice’ due to mobility
Breast carcinoma - Malignant neoplasma and commonest cause of female death. >50yrs mainly. Invades local structures
Where do most cases of colon cancer arise and why?
Glandular epithelium = adenocarcinoma.
It is the area exposed to the highest concentration of carcinogens and has a high turnover rate, making it susceptible to mutations.
How does cecum or ascending colon cancer present?
Often polypoid and rarely causes obstruction.
Weight loss and anaemia from low grdde blood loss
How does sigmoid colon cancer present?
Most common site. Stenosing and causes bowel obstruction.
Altered bowel habit, constipation due to hard stool and narrow lumen or diarrhoea as only watery stool passes through.
What specimens can be obtained from a neoplasm and how are they obtained?
Biopsy - small piece of tissue from endoscopy or needle / punch biopsy
Cytology specimens - individual or small group of cells from smears, brushing, fluids, FNA
Surgical resection
Why are specimens needed?
To confirm diagnosis and identify histology type to plan future treatment.
A surgical resection can be used to see if the resection had good margins.
What is offered to a Pt if metastasis is established?
No surgery
Chemo or radiotherapy
What are the limitations of biopsies?
Tumours are heterogenous and have varying appearances in different parts so may not select all types.
Targeting the lesion may be difficult do to size or accessibility or near vulnerable/dangerous structures.
Why can pancreatic cancer not be biopsied?
Because there is a surrounding stromal reaction occurring at the site, would lead to rapid deterioration and seeding.
What are the advantages and disadvantages of cytology specimens?
Obtained via less invasive methods e.g. cystoscopy and FNA uses a thinner needle than biopsy.
Provides access to sites not suitable for biopsy due to thin needle.
Smaller tissue samples but may make interpretation more difficult
Why might a surgical resection be used?
With the aim to cure.
Also used in pallative treatment to reduce symptoms.
To determine if further treatment is required and if good margins.
What does a resection confirm?
The diagnosis
Aggressiveness and grade of tumour
Extent of spread = staging and node involvement
Resection margins
necrosis or haemorrhage
Micro and macro - shape, size, histology, origin
What does staging show?
The extent of spread and therefor determines prognosis.
Name three types of staging.
TNM
Duke’s system for colorectal
Breast cancer uses T1-T4 for description of invasion into chest wall
What increases the stage of cancer if present?
Capsular or vascular invasion
What data must be included in a histopathology report?
Prognostic information Data for cancer registration Quality of resection feedback Adjuvant therapy decision Evealuate effectiveness of neoadjuvant therapy
What is immunohistochemistry?
A fluorescently labelled Ig used to identify an Ig bound to an antigen of a cell.
How is immunohistochemistry used to estabilish malignancy ?
Reactive inflammatory infiltrates will have a mixed population of mostly T and some B cells.
Neoplastic infiltrates with have a PURE population of cells, composed of B cells, showing clonal population
How is immunohistochemistry used as a prognostic marker?
Show cell turnover
Determines the metastatic potential and grade
How is immunohistochemistry used to identify theraputic options?
The expression of a specific antigen marker will identify if the tumour is likely to respond to specific targeting therapies that target these antigens.
e.g. HER2 in breast cancer = Herceptin
Oestrogen R in breast = Hormonal Tx
What is in-situ hybridisation?
A molecular technique that uses probes to recognise specific DNA sequences within tissue sections. Can test for kappa and lamda chains for the presence of plasma cell infiltrates for reactive v neoplastic.
EBV is encoded into RNA
What is post-transplant lymphoproliferative disease and what causes it?
An abnormal lymphoid proliferation when immunosuppressed. May be due to polyclonal lymphoid hyerplasia or monoclonal malignant lymphoma.
Which virus is mostly associated with PTLD?
EBV - Virus infects B cells and remains latent under control of T cell response but when imunnosuppressed T cell function is reduced and EBV proliferation within B cells occurs.
How does PTLD present?
Within 12 months post-transplant with focal masses or diffuse infiltrates.
How can extracted RNA or DNA be used in diagnosis?
Can identify Ig gene rearrangments ot TCR rearrangement to demonstrate clonality in B and T cell neoplasms. Determines gene mutations and the treatment options.
Why is a MDT needed?
To make decisions regarding diagnosis, treatment etc using the specialist knowledge from a variety of different HCP.