Cytology of cutaneous masses Flashcards
Why is Cytology not a substitute for histology?
- May not give definitive diagnosis
- Samples may be non-diagnostic
- poor technique
- some lesions do not exfoliate readily – some samples are hard to take
- Cannot grade tumours
- Cannot assess local infiltration – cant tell what the structure is and cannot tell how much of this is getting into outside tissues
How can cytology help us?
Draw a flow diagram for cutaneous lump cytology diagnosis?
Ask yourself
Are there cells on this smear i.e., can I write a report?
Sometimes there are so many cells on the smear, that they are all on top of each other and cannot be penetrated by the stain – in this case, scan around the edges of this mass
Are there a lot of neutrophils present, i.e., is this inflammatory?
Classify: degenerate/non-degenerate neutrophils, sepsis, other inflammatory cells and reactive cell populations – can we see any organisms?
What are the non-inflammatory tissue cells
Epithelial, round, mesenchymal – after this:
Are they benign or malignant?
Define Skipocytes?
A term that means that we just ignore them!
Not helpful for diagnosis – SKIPOCYTES IS NOT A REALY WORD OR THING – just something we ignore when we see. Sometimes called basket cells, smudge cells etc. – they aren’t cells, they are broken cells and the remnants that are left over
Describe the cytology of inflammatory lesions?
Septic inflammation
- Septic means it has BACTERIA in but could also mean fungi, or viruses – but means infected by infectious organisms. Doesn’t just mean bacteria
Pyogranulomatous inflammation
- Mixture of neutrophils and macrophages
Steatitis / panniculitis
- Inflammation in fat or sub cutic
Granulomatous inflammation
- Without neutrophils, just macrophages
Eosinophilic inflammation
- Just eosinophilic
What are the causes of acute inflammation?
- Bacterial infection – look on 100X for bacteria
- Foreign body
- Trauma
- Tumour necrosis
- Big outpouring of neutrophils
Can see cocci in a neutrophil in this image
What is this?
Norcardia and Actinomyces
Filamentous bacteria – like a fur ball!
When do bacteria indicate infection and when do they indicate contamination?
When do bacteria indicate infection?
- Marked inflammatory response
- Bacteria in neutrophils
- Degenerate neutrophils – suggest neutrophils are dying in battle! Neutrophils come out of bone marrow, into circulation and hang out in vessel walls ready to move into tissues when there is an inflammatory demand, when they end up into tissue– they die. If bacteria around, they become degenerate, nucleus swells up and becomes paler in colour
When do bacteria indicate contamination?
- No inflammation
- Mixed population of bacteria
- Not within neutrophils
Learn this as you f*cked this up last time?
What can be seen to be happening here?
Degenerate neutrophils
Karyolysis - nucleus swollen, pale staining, ragged outline
Due to bacterial infection or tissue necrosis e.g. necrotic tumour
What is seen to be happening here?
Non-degenerate neutrophils
Similar to those in circulation – except for super condensation style of the nucleus, hyper segmentation – this is neutrophils growing old by themselves and dying rather than dying due to infection
+/- karyorrhexis / pyknosis - condensed dark staining blobs of nuclear material
Seen in sterile environment or after antibiotic therapy
Describe the characteristics of benign tumours?
- Cells small and similar size
- Small uniform nuclei
- Low nuclear: cytoplasmic ratio
- Smooth granular chromatin
- +/- 1 or 2 small nucleoli - smooth regular shape
- Smooth / invisible nuclear membrane
- Cytoplasm visible around nucleus
- Ordered cell arrangement
- Cells and nuclei parallel (streaming)
- Description fits epithelial cells quite well – lymphoma is an opposite scenario
- Nuclear membrane well defined, cells have some kind of arrangement to them
What is the cytological criteria of malignancy?
- Abnormal location
- Architecture not normal for that place it is
- Cytoplasmic features
- Cell features
- Nuclear features
- Haphazard cell arrangement
- Loss of cohesion
- Loss of contact inhibition – can change size and shape. Suggest cells get to be whatever size and shape they want, push others out of shape etc.
- Chaotic arrangment
–> photo shows some mitotic figures and disorder mitosis going on. A whole pile of lymphocytes.
Describe why loss of cell adhesion occurs with malignancy?
- Caused by down regulation of the adhesion molecules
- Increased Malignancy leading to decreased Cohesion
- Usually associated with increased exfoliation
- Hypercellular sample
- This can also be affected by the sample preparation!
What are the Cell features of Malignancy?
Macrocytosis – large cells
Anisocytosis - variation in cell size
What are the nuclear criterias of malignancy?
Anisokaryosis – variation in nuclear size
Multinucleation
Coarse or clumped chromatin
Nucleoli: prominent, large, angular, irregular, variably sized
Increased mitotic activity and atypical mitoses
Nuclear fragmentation and thickening of the membrane
High or variable N:C ratio
What can be seen her that signals malignancy?
Mesenchymal borders not very well defined, not clear where the cytoplasm stops – the long purple thing with fuzzy edges
What signal of malignancy can be seen here?
Abnormal mitoses
What is the Cytoplasmic Criteria of Malignancy?
- Basophilia
- Vacuolation
- Distended with secretory product (signet-ring)
- Cytoplasmic features can be influenced by non-neoplastic processes such as inflammation
How do epithelial, mesenchymal and round cell tumours appear?
Describe Epithelial skin tumours?
- Sheets or cohesive clusters
- Often well-defined cell borders
- Cells can be:
- Angular squamous cells
- Cuboidal or columnar
- Roundish, polygonal
- Examples:
- Thricoblastoma (basal cell tumour)
- Trichoepithelioma (hair follicle tumour)
- Squamous cell carcinoma
- Sebaceous cell tumours-adenoma (they are adenoma because they are secretory), carcinoma, epithelioma
- Anal sac apocrine adenocarcinoma
- Perianal gland adenoma
Describe Mesenchymal skin tumours?
- Arise from connective tissue, muscle, bone & cartilage, nerve, endothelial cells
- Cells in non-cohesive aggregates or individually
- Cell borders are variably defined and often indistinct
- Embedded in matrix
- Spindle shaped cells with cytoplasmic tails common – cytoplasm can go off in any direction
- Cells can be oval or plump
How do Mesenchymal skin tumours appear when they get more malignant?
Increased malignancy leading to cells getting plumper, tails get shorter so the N:C ration increases
How do lipomas appear cytologically?
- Adipocytes with small nucleus and abundant vacuolated cytoplasm
- Free fatty droplets
- NB cells may fall off slides during staining / fixation
- Avoid methanol fixation (Soln. A) – try heat fixation instead and use soln’s B & C only
- Subcutaneous fat appears identical!
What is this?
Liposarcoma
Fatty background
Pleomorphic spindle cells, some with variably sized cytoplasmic fat vacuoles
Other cells similar to lipocytes with larger vacuoles
How do round cell tumours appear?
What round cell tumour could this be?
Not lymphocytes
Don’t look like plasma cells (these have more condensed nucleus)
Don’t look like mast cells
HISTIOCYTES LEFT OVER – benign process that dogs own immune system deals with
What round cell tumour does this look like?
Looks more like lymphoma
