Oncology: Cytology of Tumours Flashcards
What are the indications for cytology?
- Lesion palpable externally or seen on imaging
- Organomegaly
- Cavitary effusion
- Cancer staging
- Pyrexia of unknown origin
What are the expectations from cytology?
- Identify inflammation
- Suspect or detect infection
- Test for choice for bone marrow
- Detect neoplasia
- Differentiate between benign and malignant in most cases
- Identify cell of origin in many cases
What is the sensitivity and specificity of cytology for diagnosing neoplasia?
High sensitivity and specificity
Results are often suggestive or supportive- guide to a clinical decision rather than a definitive answer
What are your differentials for this lesion?
- Mast cell tumour
- SCC
- Sarcoma
- Foreign body lesion- mycobacterial
- Cutaneous lymphoma
- Cutaneous plasmacytoma
How are cytology slides stained?
In house
* Diffquik
* Wear gloves
* 10 dips in each
* rinse the slide- deionised
External labs- different stains
How should a slide be examined?
- Naked eye- labeled, macroscopic (staining)
- 4-10x- scan, chose most respresentitive area
- 10x- identify different types of cells
- Higher magnification
Whats the problem with this slide?
Ruptured cells
Incorrect sampling/smearing
What is the problem with this slide?
Inadequate staining
* Insufficient time
* Inadequate drying prior to staining
* Layer of cells too thick
* Too close to histo pot- formalin fumes
What are the problems with the following slides
a) Formalin fumes
b) Hb crystals (condensation)
c) Stain precipitate
d) Ultrasound gel or lube
e) serum activator
Is this tumour or inflammation
Inflammation
What are the predominant inflammatory cells?
- Neutrophils- acitve/recent
- Macrophages- chronic
- Lymphocytes and plasma cells
- Eosinophils- inflammation/parasites
If inflammation can be ruled out then likely to be neoplasia
What can commonly be misinterpreted as malignant cells post biopsy?
Reactive fibroblasts
What are the three cell types of neoplasia?
Epithelial cells
* Skin, gut, glandular
Mesenchymal
* Connective tissue, muscle
Round cells
* Immune system
How should the cell arrangement and shape be assessed?
Arrangement
* Discrete of cohesive
* Cytoarchitecture
Cell shape
* Round
* Polygonal
* Spindle
Identifies type of neoplasia
- Where do skin tumours most frequently arise from?
- How malignant are skin tumours usually in dogs/cats?
- Adnexa- hairfollicle (contains keratin), glands
- Dogs benign, cats malignant
What are the types of round cell tumours?
- Histiocytoma
- Plasma cell tumour
- Mast cell tumour
- Lymphoma
What neoplasm is this the classical appearance of?
‘Islands’ of cells: epithelial tumours
What type of neoplasm is this?
Round cells- lymphoma
What kind of tumour is this?
Spindle cells with indistinct edges embedded in ECM
Mesenchymal
What type of neoplasm is this?
Mesenchymal
* Often present in small numbers
* Comet shaped or wind mill arms
* Soft tissue sarcoma
What kind of neoplasm is this?
Lipoma
Not possible to differentiate from normal subcut fat
What are possible non-neoplastic, non-inflammatory lesions?
Keratinising cysts
* Sebaceous cysts
* Benign biological behaviour
Sebaceous hyperplasia
* Raised, hairless, cauliflower shaped
* Cytologically identical to sebaceous adenomas
Hamartoma
- How is a hair follicle tumour identified?
- What is the problem with their cytology?
- Why is no 2 irrelvent
Trichoepithelioma, Keratocanthoma, Pilomatriochoma
- Accumulate keratin and cellular debrid
- Cytology cannot differentiate specific type
- Most have similar benign biological behaviour
What could this lesion be?
from skin
Sebaceous hyperplasia/adenoma
What are the criteria of malignancy?
Nuclear criteria- stronger
* Multinucleation
* Karyomegaly
* Mitoses
* Nuclear moulding
* Large, angular, variably sized nucleoli
Cytoplasmic criteria
* Hypercellularity
* Pleomorphism
* High/variable cytoplasm: nucleus ratio
Using malignancy criteria how can malignancy be determined?
If present- malignant neoplasia
* Minimum of 3 criteria
If absent- benign or well differentiated malignant
What is the cell type
Epithelial
What is the cell type?
Mesenchymal
What is the cell type?
Round- Histocytes
Lots of cytoplasm (atypical)
What type of round cell tumour is this?
Mast cell tumour
Fried egg like appearance
Intracytoplasmic granules
What neoplasms are not easily classified as round, epithelial or spindle?
- Endocrine or neuroendocrine- epithelial or spindle
- Histocytic sarcoma, chondrosarcoma and oesteosarcoma- round or spindle
- Melanoma- several
