LRT Neoplasia in SA Flashcards
1
Q
How are tumours sub-classified?
A
- By tissue of origin
- Then by benign vs malignant
- But remember, when talking to clients, they won’t know what a tumour is – tell them if it is cancerous or not!
2
Q
Explain Lymphoma
A
- Lymphoma = lymphosarcoma = malignant
- Subclassified histologically by:
- cell type
- grade (cellular differentiation, mitotic rate etc)
- Cell distribution (diffuse/ nodular)
- Also immunophenotyping and anatomic site
- B vs T – very simplistic
- Multicentric, alimentary, thymic, cutaneous, extranodal
- Remember paraneoplastic problems
- Chemo and radiation sensitive
- Rarely considered a surgical disease
- Chemo and radiation sensitive
3
Q
Explain Leukaemia
A
- Leukaemia = any bone marrow derived haematopoetic neoplasm
- Lymphoid vs myeloid (anything NOT a lymphocyte) cell lines in origin
- Rarely see erythroleukaemias
- Acute (AML/ ALL) vs chronic leukaemia (CLL/CML)
- Chronic > acute chemosensitivity
- Lymphoid vs myeloid (anything NOT a lymphocyte) cell lines in origin
- Multiple myeloma = plasma cells
- Secrete excess Igs of one clonal class
- Usually present due to paraneoplastic signs
- Chemosensitive
- MDS = myelodysplastic syndromes
- Pre-malignant in some variants
4
Q
Characteristics of benign vs. malignant tumours
- Growth rate
- Growth manner
- Effects on adjacent structures
- Mets
- Effect on host
A
Benign
- Growth rate: relatively slow
- Growth manner: Expansive
- Effects on adjacent structures: Often minimal pressure necrosis and deformity
- Mets: doesnt occur
- Effect on host: often minimal. though serious if develops in brain or obstructs GIT.
Malignant
- Growth rate: often fast
- Growth manner: invasive
- Effects on adjacent structures: invades and destroys
- Mets: present via lymphatics, haematogenous and transcoelomic spread
- Effect on host: often life threatening
5
Q
Where can tumours arise?
A
- Nasal planum
- Nasal cavity
- Tonsils, larynx, pharynx, trachea
- Mediastinum
- Thyroid
- Thymus
- Heart and great vessels (see RJ lectures)
- Lung parenchyma
- Pleura
- Ribs
Bold = can see them, otherwise, quite challenging
6
Q
What clinical signs might you see with tumours located in:
- Nasal
- upper airways
- Lower airways and pulmonary
- Mediastinal
- Pleural
- Cardiac
A
- Nasal
- Discharge (blood)
- Nasal sturtor
- upper airways
- larynx and trachea
- Changes in vocation
- Resp. stridor
- larynx and trachea
- Lower airways and pulmonary
- Dyspnoea (but with pulmonary parenchyma it is much less likely)
- Chronic weight loss
- lethargy
- Mediastinal
- Dyspnoea
- Cranial mediastinal area often very dull
- Pleural
- Similar to mediastinal, but often diffuse, so loss of lung sounds
- Increased resp inspiratory and expiratory effort
- Cardiac
- Not much - may present collapsed, arrhythmiasa, oedema etc.
7
Q
Nasal planum neoplasia
A
- White cats with solar exposure, rare in dogs
- Carcinoma in situ àsuperficial SqCC àinfiltrative SqCC, locally invasive, mets rare.
- Locally problematic, but rarely mets. Also seen on the pinna.
- Therapies: Photodynamic therapy (PDT), planectomy (biopsy may cure!), immunomodulators (imiquimod)
- Good prognosis with nose off, may need repeat PDT
8
Q
Nasal cavity disease investigation methods
pros and cons of:
- Radiography
- MRI
- CT
- Rhinoscopy
A
Radiography
Pros
- Relatively cheap
- Readily available
- Quick to perform
Cons
- Superimposition – will have to be intra-oral film, poor resolution.
MRI
Pros
- Gold standard for soft tissue
Cons
- Expensive
- Long time
- GA required
CT
Pros
- Gold standard for bony involvement
- Cheaper than CT, more accessible.
- Quicker to perform cf. MRI – which will need an anaesthetic cf. sedation for CT.
Cons
- No good for soft tissue
Rhinoscopy
Pros
- Can see something and biopsy at same time – targeted samples.
- Can see mucosa
Cons
- Invasive
- Traumatic
- Structure of nose – not empty, full of turbulent bones, so difficult to see easily. So sensitivity is very poor – cannot tell you nothing is there, but specificity is good – if you see something abnormal, can take a biopsy and get a diagnosis.
9
Q
Nasal cavity tumours
A
- 3% of all neoplasms dogs and cats are nasal tumours.
- Dogs: carcinomas, rarely SqCC, lymphoma, fibrosarcomas, chondrosarcomas and osteosarcomas
- Cats: adenocarcinoma or lymphoma > others
- Investigation: MRI/ CT (usually CT) then rhinoscope and biopsy
- If see a lump on CT, measure it, plan where the lump is and measure where biopsy needs to get to without needing rhinoscopy.
- Therapy: radiotherapy+/-chemo +/NSAIDs
- Little apparent benefit of surgical resection
- Margins and morbidity
- Exceptions?
- Guarded prognosis (dog carcinomas approx 250 days MST with radiotherapy or NSAIDs)
10
Q
Larynx and trachea tumours (URT)
A
- RARE
- Cats: laryngeal lymphoma recognised, very similar granulomatous proliferation
- Dogs: oncocytoma/rhabdomyosarcoma, tracheal cartilaginous tumours, OSA, fibrosarcoma, SCC
- Usually diagnosed on examination under anaesthesia, then biopsy if possible
- Animals that have changes in resp noise, might not be apparent during normal PE until GA.
- Tracheal masses may be benign so can be resected, difficult surgery - refer
- Need for permanent tracheostomy rare but may be required.
11
Q
Pulmonary parenchyma neoplasias (cancer of the lung)
A
- Primary lung tumours are very rare in comparison to humans (1%)
- Dog>cat, weak links with passive smoking
- Metastatic disease by far the commonest
- Oral melanoma, thyroid Ca, osteosarcoma, haemangiosarcoma and mammary Ca.
12
Q
Primary lung cancer
A
- Median age 11 years
- Generally carcinomas, classified by location, often hard to tell exact origin
- Can also see pulmonary lymphoma, pulmonary lymphomatoid granulomatosis, malignant histiocytosis
- Rare to see mesenchymal tumours in the lung
- >50% solitary (often right caudal lobe)
- Present with non productive cough or exercise intolerance
- Long standing low grade cough.
- Hypertrophic osteopathy as rare paraneoplastic disease
- Often lose weight.
13
Q
Metastatic disease and therapy
A
- May be incidental finding or present with cough/ tachypnoea
- May be the first an owner knows about animal having cancer
- Commonest = osteosarcoma, haemangiosarcoma, thyroid carcinoma, melanoma of the mucocutaneous junction
- check pre-op!
- Remember not all tumours met to the chest
- Interesting but no great merit in finding 1◦ if no plans to treat
- Emphasis on finding mets?
Met therapy
- Solitary metastasis removal increasingly common
- Need CT to get best info on how many and where, and slow radiographic doubling time
- Thoracoscopic approaches increasing
- Care on seeding to portal sites
- May start getting locally delivered chemo
- Delivery and penetration problems
- Median survival time 3 months with no tx
- Unclear survival if early detection on CT
14
Q
Mediastinal disease overview
A
- May be benign or malignant tumours, cystic lesions, enlarged mediastinal lymph nodes or haematomas
- Pros and cons of diagnostic imaging as for lung masses though CT very useful if surgical
- May be hidden behind pleural effusion – check tracheal position
- Diagnosis can be very challenging however important as clear distinction in treatment options for e.g. lymphoma vs sarcoma
- Surgery not indicated for lymphoma.
15
Q
Mediastinal lymphoma
A
- Commonest in young cats (predisposition for siamese?), also seen in dogs with multicentric or stage 3-5 lymphoma if so is considered a negative prognostic indicator
- Tachypnoea, inspiratory hyperpnoea, dull heart sounds, pleural effusion (cytology for dx)
- Non compressible anterior mediastinum
- NB practice compressing normal
- Check compressibility of the cranial chest – if mass there, you cannot compress the chest.
- Check FeLV/ FIV status (~50% positive for FeLV)
- DDx thymoma – consult a cytologist!
- Thymoma is surgical
- Treatment: chemo +/- radiotherapy?
- Generally remission, cure rare
