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SMALL ANIMAL > 23.11.4: Cutaneous masses > Flashcards

23.11.4: Cutaneous masses Flashcards

1
Q

How could you decide what a cutaneous mass is?

A
  • Signalment
  • History: general, dermatological, speed of onset
  • Clinical exam: general and dermatological
  • Ranked ddx list
  • Investigations: cytology (FNA), tissue biopsy (histopathology ± tissue culture if inflammatory)
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2
Q

What are the main types of skin mass (i.e. that you could differentiate on FNA)?

A
  • Inflammatory
  • Cyst
  • Neoplastic
  • (hyperplastic/dysplastic - less common)
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3
Q

What are some example causes of an infectious (septic) inflammatory cutaneous mass?

A
  • Bacterial infection
  • Fungal infection
  • Protozoal infection
  • Ectoparasite e.g. Demodex
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4
Q

True/false: FNA cytology from a neoplastic mass is likely to contain a clonal cell population.

A

True
Clonal population = lots of the same cells

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5
Q

If a cytological sample is describe as showing ‘pyogranulamtous inflammation’, what cell(s) will be present?

A

Neutrophils (‘pyo’) and macrophages (‘granuloma’)
* The presence of granulomatous inflammation implies a deeper infection as macrophages are not typically found at the surface.

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6
Q

What is a cyst and what are its content?

A

Cyst: epithelium lined cavity. The contents will be whatever that epithelium is making.

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7
Q

True/false mycobacteria can be easily identified using in-house stains.

A

False
Special labs will be needed to identify mycobacteria. Failure to identify them does not indicate the mass is sterile.

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8
Q

A mass has been identified as neoplastic on cytology. What is the next step?

A

Categorise the cell population as:
* Epithelial cell
* Round cell
* Mesenchymal (spindle) cell

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9
Q

True/false spindle cell tumours exfoliate well.

A

False
Spindle cell tumours do not exfoliate well.

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10
Q

What might mast cell degranulation result in?

A

Urticaria
Angiogenic oedema

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11
Q

If degenerated collagen is the cause of the lesion, what associated disease might we see?

A

Eosinophilic granuloma
Arthropod bite granuloma

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12
Q

If fatty acids/lipids are the cause of the lesion, what associated disease might we see?

A

Sterile panniculitis

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13
Q

Once we have classified a skin mass as inflammatory, how can we further describe it?

A
  • Infectious (septic)
  • Non-infectious (sterile)
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14
Q

What are some examples/causes of a non-infectious inflammatory skin mass?

A
  • Urticaria/angioedema
  • Eosinophilic granuloma
  • Arthropod bite granuloma
  • Sterile panniculitis
  • Haematoma
  • Seroma
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15
Q

Is this inflammation, neoplastia, or cyst?

A

Inflammation

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16
Q

Inflammation, neoplasia or cyst?

A

Neoplasia

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17
Q

Inflammation, neoplasia or cyst?

A

Cyst with cholesterol crystals

18
Q

You have identified an inflammatory skin mass. What questions do you need to ask next?

A
  • Predominant inflammatory cell type? i.e. neutrophilic/eosinophilic/pyogranulomatous
  • Sterile vs septic? Remember not to assume sterile just because no organisms were found
19
Q

What is a malignant mesenchymal cell tumour called?

A

sarcoma

20
Q

What is a benign epithelial cell tumour called?

A

Papilloma
Adenoma

21
Q

What is a malignant epithelial cell tumour called?

A

Carcinoma
Adenocarcinoma

22
Q

Inflammation, neoplasia, or cyst?

A

Neoplasia: mesenchymal cell tumour.

23
Q

Inflammation, neoplasia or cyst?

A

Cyst
There are squames and material in the background but not really clearly identifiable cells.

24
Q

Inflammation, neoplasia or cyst?

A

Inflammation
Neutrophils and macrophages present

25
Q

What causes urticaria and angiogenic oedema (angioedema)?

A
  • Degranulation of mast cells or basophils
  • Immunological or non-immunological causes
  • Immunological: Type I or III hypersensitivites, mast cell tumours
  • Non-immunological: physical forces (pressure, sunlight, heat, exercise), genetic abnormalities, drugs/chemicals (inc. food), venomous insects, plants
26
Q

Treatment of urticaria

A
  • Many cases resolve spontaneously in 12-48hrs; owners should be instructed how to monitor for anaphylaxis
  • If needed, can be dexamethasone IV / prednisolone 1mg/kg q24hr for 3-5 days and taper, ± oral antihistamines
  • Give adrenaline if signs of anaphylaxis
27
Q

What is calcinosis cutis?

A

Calcinosis cutis: inappropriate deposition of calcium/phosphate in the skin/subcutis -> gritty white deposits, often with surrounding inflammation

28
Q

What causes calcinosis cutis?

A
  • Dystrophic calcification (e.g. HAC)
  • Metastatic calcification: deposition associated with altered serum of calcium/phosphorus e.g. chronic renal disease.
  • Idiopathic e.g. Calcinosis circumscripta
29
Q
A

Calcinosis cutis

30
Q
A

Aural haematoma

31
Q

What causes a haematoma?

A

Damaged/ruptured blood vessel bleeds into/under skin.
* Usually traumatic cause, but occasionally linked to clotting factor deficiencies/toxic causes (check history for these)

32
Q

Describe the cytology you might expect if you sampled a haematoma

A
  • Initially the same as a blood smear although no platelets
  • Macrophages engulfing RBCs and fibroblasts may appear
33
Q

Describe treatment of a haematoma

A
  • Find cause and address if necessary
  • Usually self-limiting - keep quite, apply pressure bandage
  • If acute, severe haemorrhage, identify source and ligate. Consider antibiotic cover if risk of secondary infection.
  • In some cases, surgery may be required e.g. aural haematoma
34
Q

Seroma

A

accumulaton of sterile fluid (filtrate of blood) under a wound.
* The swelling is soft, non-painful, and there is not heat on palpation.
* FNA shows straw-coloured/blood-tinged fluid.

35
Q

Describe management of a seroma that formed after surgery

A
  • Conservative unless refractory or causing wound disruption (may take several weeks)
  • If pressure bandaging, change bandage every 48hrs
  • Keep animal quiet and confined
  • Repeated drainage only if size is causing discomfort (likely to reform and risk of introducing infection)
  • If severe: surgical debridement, flushing with isotonic solution, careful apposition of tissues, insertion of Penrose drains, biopsy and culture
36
Q
A

Arthropod bite granuloma

37
Q

Describe the management of an arthropod bite granuloma

A
  • Check no evidence of retained arthropod/mouthparts (esp tick)
  • May resolve without treatment
  • Could do short course topical corticosteroid
  • If not resolving, consider surgical removal, submission for histopath, tissue culture to confirm diagnosis (would need to be off corticosteroids for 2 weeks before sampling for histology)
38
Q
A

Panniculitis: inflammation of the subcutaneous fat.
* Presents as single/multiple nodules ± draining sinuses
* Easily confused with bacterial abscess
* Can be sterile or infectious in origin

39
Q

This is the FNA from an animal presenting with multiple nodules and some draining sinuses. What are your thoughts?

A
  • This FNA shows pyogranulomatous inflammation with background fat
  • Presenting signs consistent with panniculitis
  • Need to take samples for histopath and bacterial and fungal tissue culture -> rule out infection as initial step
40
Q

Describe the management of panniculitis

A
  • Correct underlying cause if possible
  • e.g. foreign material -> excise if solitary lesion
  • e.g. 2 address nutritional imbalances

If still no resolution
* If solitary lesion -> surgical excision if possible
* If multifocal lesion -> immunosuppressive therapy (must check for infection prior to starting this!)

41
Q
A

Mast cell tumour
(This is a round cell tumour)

SMALL ANIMAL (90 decks)

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