Cutaneous masses Flashcards

Approach to cutaneous masses, cytology of cutaneous masses

1
Q

What are the groups that cutaneous masses can fall into?

A
  • Inflammatory (infectious, non-infectious)
  • Neoplastic
  • Non-neoplastic, non–inflammatory i.e. cysts
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2
Q

Describe what is meant by a nodule

A
  • A solid swelling of tissue >1cm
  • Circumscribed, solid elevation
  • Usually extends into deeper skin layers
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3
Q

Describe what is meant by a cyst

A
  • An epithelium lined cavity containing fluid or solid material
  • Smooth, well-circumscribed, fluctuant/solid
  • If emptied, will fill up again
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4
Q

Give examples of swellings of non-dermatological origins

A
  • Hernias
  • Oedema
  • Emphysema
  • ## Mammary tumours
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5
Q

Describe emphysema

A
  • Gas in subcutaneous tissue

- Crepitant without pain or swelling, feels like bubble wrap

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6
Q

What are the potential causes of emphysema?

A
  • Severe respiratory disease or lung puncture
  • Introduction or air through cutaneous wound
  • Rumenotomy or rumen cannulisation
  • Clostridial infections (gas produced by clostridial organism)
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7
Q

Explain the role of FNAs in the diagnosis of cutaneous mass lesions

A
  • Gives an idea of the cellular processes taking place in a lump
  • Degree of exfoliation can give indication of what cell types are present
  • Can identify if there are microbes present, normal cells, inflammatory cells, neoplastic cells
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8
Q

What is required in order to be able to diagnose a cutaneous mass lesion?

A
  • History
  • General clinical examination
  • Dermatological examination
  • Cytology
  • Tissue biopsy
  • +/- immunohistochemistry
  • ## +/- tissue culture
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9
Q

Why is age important in the history for the diagnosis of a cutaneous mass lesion?

A
  • Certain lesions are more likely at certain ages

- E.g. <4mo: juvenile cellulitis, >2yo: histiocytoma (dog), >6yr: neoplasia

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10
Q

What should be included in the history for a cutaneous mass lesion?

A
  • Age
  • Travel
  • Breed
  • History of trauma/fight
  • Systemic signs
  • Speed of onset of tumour
  • Prior history of neoplasia
  • Recent injections
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11
Q

Why is travel an important part of the history for cutaneous mass lesions?

A
  • Leishmaniasis
  • Systemic fungal disease
  • Exotic diseases such as the above can cause cutaneous masses
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12
Q

What could paraneoplastic signs be suggestive of with a cutaneous mass lesion?

A

e.g. haematemesis with mast cell tumour

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13
Q

What may respiratory signs, weight loss and lethargy be suggestive of with a cutaneous mass lesion?

A
  • Systemic/metastatic neoplasia

- Systemic function infections

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14
Q

What may depression or inappetance be suggestive of with cutaneous mass lesions?

A

Some microbial infections, abscesses

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15
Q

With what types of cutaneous masses may pyrexia occur?

A

With systemic/severe cutaneous microbial infections, abscesses

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16
Q

What types of cutaneous masses might cause peripheral lymphadenopathy?

A
  • Neoplastic (metastatic spread to lymph nodes)

- Infectious/inflammatory causing reactive hyperplasia/lymphadenitis if spread

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17
Q

List the features that should be identified and characterised by the dermatological examination of a cutaneous mass

A
  • Solitary or multiple lesions?
  • Area of body and size
  • Well vs ill defined
  • Freely moveable or attached
  • Draining tracts/sinuses?
  • Pitting on pressure
  • Presence or absence of pain
  • Inflammatory (can indicate neoplastic or inflammatory lesion)
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18
Q

What is the advantage of no-suction FNAs?

A

Less likely to damage cells

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19
Q

What cytology techniques can be used in the investigation of cutaneous masses?

A
  • FNA

- Impression smears

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20
Q

What would you expect to see on cytology of an inflammatory mass lesion?

A
  • May be sterile or infectious, acute or chronic
  • May see microbes
  • Neutrophils (acute), macrophages (chronic)
  • +/- eosinophils
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21
Q

What would you expect to see on cytology of a neoplastic mass lesion?

A

Round, epithelial or spindle cells in neoplastic arrangement i.e. conal population, pleomrphism etc.

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22
Q

Describe the cytological appearance of a cystic mass lesion

A
  • Depends on what is lining the epithelium

- Amorphous collection of cells

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23
Q

What are the key limitations of cytology in the investigation of cutaneous mass lesions?

A
  • Not all cell-types are shed easily, may not always be representative/diagnostic
  • May take an unrepresentative sample
  • Gives no information re. the tissue architecture, therefore cannot grade neoplasm if present
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24
Q

What are tissue biopsies used for with cutaneous mass lesions?

A

To confirm putative diagnosis from FNA or where FNA is inconclusive, or for tissue culture where needed

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25
Q

Describe an elliptical incisional biopsy

A
  • Includes margin of normal to abnormal
  • Taken from representative area
  • Need to remove whole biopsy tract when mass is removed
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26
Q

Describe an elliptical excisional biopsy

A
  • May cure benign, non-infiltrative neoplasms
  • Remove deeper tissue en bloc so can assess all margins, but can nerver confirm 100% excision
  • DO NOT perform if suspect infiltrative mass
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27
Q

When are punch biopsies mostly used?

A

For inflammatory lesions, not so useful for neoplasms

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28
Q

When should lymph nodes be biopsied?

A
  • FNA all enlarged lymph nodes

- If firm node negative for neoplasia on FNA, take excisional biopsy under GA for histopath

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29
Q

Outline the role of immunohistochemistry in the diagnosis of cutaneous mass lesions

A
  • Labels cell-surface markers to help identify pheotype of cells in neoplasms
  • Highly anaplastic cells may still remain unidentifiable
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30
Q

When and how should tissue culture be performed in the diagnosis of cutaneous mass lesions?

A
  • If deep infection is a possibility
  • Take when sampling for histopath to save second procedure
  • Trim off surface epidermis to avoid contamination of sample with surface organisms or antibacterial scrub solutions
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31
Q

List the potential origins of cutaneous tumours

A
  • Epithelium
  • Mesenchyme (spindle cell)
  • Round cells
  • Melanocytes
  • Metastases from non-cutaneous neoplasm
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32
Q

List the most common causes of cutaneous tumours of farm animals

A
  • Papillomatosis
  • Enzootic bovine leukosis
  • Sporadic bovine leukosis
  • Lymphosarcoma in pigs
  • Cancer eye (SCC in cattle, usually UV associated, periorbital or orbital)
  • SCC of sheep and goats: often vulvae, perineal, pinnal, papilloma-virus associated in sheep
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33
Q

Compare the proportion of benign to malignant skin tumours in dogs and cats

A
  • Most skin tumours in dogs are benign (2/3)

- Most skin tumours in cats are malignant (2/3)

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34
Q

List the most common malignant skin tumours of dogs (inn order from most to least common)

A
  • Mast cell tumour
  • Soft tissue sarcomas
  • Malignant melanoma
  • Squamous cell carcinoma
  • Epitheliotropic lymphoma
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35
Q

Name the main benign skin tumours of dogs

A
  • Histiocytoma
  • Papilloma
  • Lipoma
  • (histiocytoma and papilloma may regress spontaneously)
  • Sebaceous hyperplasia/adenoma
  • Melanoma
  • Basal cell tumour
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36
Q

List the most common feline skin tumours (in order from most to least common)

A
  • Fibrosarcomas
  • Squamous cell carcinomas
  • Basal cell tumours
  • Mast cell tumours
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37
Q

What are the 3 golden rules in the approach to cancer cases?

A
  • Establish the diagnosis (type and grade of tumour)
  • Establish the stage of disease
  • Investigate any complications
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38
Q

What are the treatment options for cutaneous neoplasia?

A
  • Surgery
  • Chemotherapy
  • radiotherapy
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39
Q

In what cutaneous tumours would a 1cm excisional margin be sufficient?

A
  • Low grade mast cell tumours
  • Grade 1 soft tissue sarcomas
  • Well differentiated squamous cell carcinomas
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40
Q

In what cutaneous tumours would a 2cm excisional margin be sufficient?

A
  • Intermediate grade mast cell tumours
  • Malignant oral tumours e.g. fibrosarcoma, SCC, poorly differentiated carcinomas
  • Grade 2 and 3 soft tissue sarcomas
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41
Q

In what cutaneous tumours would a 3cm excisional margin be required?

A
  • Osteosarcomas that have invaded soft tissues

- Feline vaccine-associated sarcomas

42
Q

What natural barriers will limit the spread of tumours?

A

Collagen-rich, relatively avascular structures e.g. fascia, tendons, ligaments, cartilage

43
Q

Describe the typical presentation of mast cell tumours

A
  • Single or multiple nodules, cutaneous or subcutaneous
  • May mimic other masses or inflammatory conditions
  • Over half on trunk, 25-40% on extremities, 10% on head and neck
  • Scrotum, perineum, back and tail can be affected
  • Occasionally extracutaneous sites such as conjunctiva, larynx, oral mucosa
  • Often poorly haired
  • May be inflammatory: paraneoplsatic clinical signs, visible inflammation, pruritus, changing size of mass
44
Q

What signs could histamine from a mast cell tumour cause?

A
  • Inflammation, pruritus
  • +/- vomiting, gi ulceration and melaena
  • Occasional oedema/anaphylaxis
  • Collapse
45
Q

What signs could heparin from a mast cell tumour cause?

A

Local bruising and perioperative bleeding

46
Q

What is a potential outcome of proteases released from mast cell tumours?

A

Slow wound healing

47
Q

What is required in the work up of a suspected mast cell tumour?

A
  • FNA (diagnoses most MCTs)
  • Histopathology for grading
  • Assessment and aspiration of local LNs
  • Ultrasound of liver and spleen (no other imaging needed)
48
Q

Compare the metastatic potential of well, intermediate and poorly differentiated mast cell tumours

A
  • Well: rarely metastasise (<10%)
  • Intermediate
    uncommonly metastasis (5-20%)
  • Poorly: >75% metastasise
49
Q

Give the treatment options for mast cell tumours

A
  • Surgical removal best
  • Some new drugs available: masivet, palladia
  • Chemotherapy: masivet, palladia, prednisolone+vinblastine+chlorambucil
  • Radiotherapy
50
Q

Describe the typical appearance of feline squamous cell carcinoma

A

Usually develop on unpigmented nasal planum, pinnae, eyelids

51
Q

Describe the metastatic potential of feline squamous cell carcinomas

A
  • Low metastatic potential

- Very locally invasice

52
Q

Discuss the treatment of feline squamous cell carcinomas

A
  • Depends on size and site of neoplasm
  • Superficial respond well to all therapies
  • Infiltrative need aggressive surgery

Options:

  • Surgery: incl pnnaectomy, nasal planectomy
  • Photodynamic therapy
  • Radiotherapy
  • Laser therapy or cryotherapy for early, shallow lesions only
  • Imiquimod cream, for early shallow lesions
53
Q

How can feline squamous cell carcinomas be prevented?

A
  • Sunblock
  • Keep indoors in strong sunlight
  • UV light blocking film on windows
54
Q

Discuss the prognosis of canine squamous cell carcinomas

A
  • depends on site
  • Nasal planum, legs, trunk have low metastatic potential, surgery good option
  • Subungual may require amputation of digit
55
Q

Describe subungual squamous cell carcinomas in dogs

A
  • Most common canine digital tumour, esp. large black dogs
  • Differential: paronychia, as often have secondary infection/inflammation
  • Radiography needed
  • If see lysis on P3 on radiography or biopsy then amputate digit
56
Q

What are liposarcomas, fibrosarcomas, myxosarcomas and haemangiopericytomas examples of?

A

Canine soft tissue sarcomas

57
Q

Describe the malignancy, diagnosis and treatment of liposarcomas, fibrosarcomas and myxosarcomas

A
  • Variable malignancy, often local infiltration rather than distant metastasis
  • Biopsy for diagnosis
  • Radical excision after staging, or debulk + radiotherapy
  • Chemotherapy of little value due to slow turnover rate of cells
58
Q

Explain the role of biopsy in the diagnosis of canine soft tissue sarcomas

A
  • Identification of concurrent necrosis/inflammation
  • Needed for grading
  • Poor exfoliation on FNA
  • Often look similar on cytology
59
Q

Why are haemagioperictyomas different from other canine soft tissue sarcomas?

A

FNA can yield diagnosis

60
Q

Describe the appearance, metastatic potential, treatment and prognosis for haemangiopericytomas

A
  • Low grade tumours on limbs
  • Low metastatic potential
  • Treatment is wide excision or debulk +radiotherapy
  • Often recur following excision, not life threatening but are annoying and difficult to deal with
61
Q

Compare feline and canine fibrosarcomas

A
  • Generally behave the same and can be treated in the same way
  • Exception is injection site sarcomas in cats
62
Q

What should be done if suspect an injection site sarcoma?

A
  • Report via suspected adverse reaction reporting service

- Consult oncologist after biopsy but before surgery

63
Q

Name the 2 types of primary cutaneous lymphoma

A
  • Epitheliotropic lymphoma (mycosis fungoides, T cell lymphoma)
  • Non-epitheliotropic lymphoma (B cell lymphoma)
64
Q

Describe the different manifestations of epitheliotropic lymphoma

A
  • Generalilsed: scale, pruritus, exfoliative dermatitis
  • Foci of erythroderma, crusting, ulceration
  • Mutliple dermal nodules, erythematous plaques
  • Mucocutaneous lesions (depigmenting)
  • All are chronic and may wax and wane initially
65
Q

Compare the prognosis of epitheliotropic and non-epitheliotropic lymphomas

A
  • Epitheliotropic better, unpleasant due to extent of lesions but does not kill animal very quickly
  • Non-epitheliotropic carries grave prognosis, metastasise rapidly. Presence of nodules carries worse prognosis still
66
Q

Discuss the treatment of non-epitheliotropic lymphomas

A
  • Median survival time is only months
  • Chemotherapy: retinoids, CCNU (lomustine) or COP
  • Surgery possible if solitary/localised
  • Surgery or radiotherapy if localised epitheliotropic lymphoma or lips/mouth
67
Q

Define a cyst

A

An epithelium lined cavity containing fluid or solid material

68
Q

Describe the contents of follicular, apocrine and sebaceous cysts

A
  • Follicular: cornified debris, tends to look very pus-y
  • Apocrine: apocrine secretions
  • Sebaceous: sebaceous secretions
69
Q

Explain the development and importance of infection in cysts

A
  • Cysts may rupture, leading to inflammation and potentially infection
  • Infection and inflammation must be resolved before excision
70
Q

Explain what is meant by dermoid cysts

A
  • Congenital defect, especially common in Rhodesian Ridgebacks, often located on dorsal midline neck/trunk
  • Filled with hair/keratinous material
71
Q

Explain the significance of dermoid cysts

A
  • Benign in the sense that it is not cancer, but cause substantial space occupying problem
  • May extend to dura mater and cause neurological problems
72
Q

What are the treatment options for non-infiltrating lipomas?

A
  • Are benign skin mass
  • Can leave if monitor intermittently following identification, and if are slow growing and causing no problem
  • Excision if are causing problems
73
Q

Describe the gross appearance, cytological appearance and treatment options for sebaceous hyperplasia/adenoma

A
  • Small cauliflower-like warts
  • If slow growing and well-circumscribed can leave and monitor
  • Excise if any change or become traumatised
  • On aspiration wil see sebaceous cells/sebocytes
74
Q

In what groups of animals are histiocytomas more commonly found?

A
  • Young dogs

- Dogs on oclacitanib

75
Q

Where are histiocytomas commonly found?

A

On the extremities

76
Q

Describe the treatment of histiocytomas

A
  • Frequently resolve spontaneously
  • Do not use steroids, may slow regression
  • Lymphocytes may be seen at base of tumour as immune system deals with these
77
Q

Describe the appearance of melanomas

A

Usually well defined, deeply pigmented dome-shaped lesions in pigmented skin

78
Q

Compare the prevalence and location of benign and malignant melanomas

A
  • > 85% are benign, but still use wide excision

- Mucocutaneous or digital melanomas are potentially malignant with widespread metastases

79
Q

Compare basal cell tumours in the dog and cat

A
  • Usually benign in dog (depending on location)

- Aggressive characteristics in cats

80
Q

Describe the appearance of basal cell tumours in cats

A
  • Solid, ulcerated or cystic

- Most common pigmented tumour in cats

81
Q

Compare the growth and treatment of basal cell tumours in dogs and cats

A
  • In dogs are slow growing, wide excision used to cure
  • In cats, aggressive on cytology/histopathology but low-grade behaviour
  • Excise with as wide a margin as possible
82
Q

List the classifications for inflammatory lumps

A
  • Can be: neutrophilic, eosinophilic,lymphoplasmalytic or granulomatous
  • Identify as: acute or chronic
  • Identify as: septic or no organisms observed
83
Q

List the classifications of neoplastic lumps

A
  • Cell type: epithelial, round, spindle

- Activity: benign or malignant

84
Q

List the classifications of cystic lumps

A
  • Haematoma
  • Seroma
  • Sialocoele
  • Epithelial/follicular
85
Q

Explain how inflammation with tissue cells may be found on cytology of a lump

A
  • May be primary neoplasia with secondary inflammation

- May be primary inflammation with secondary hyerplasia, fibroplasia or granulation tissue

86
Q

What are smudge cells and describe their appearance

A
  • Aka broken/basket cells
  • Are damaged cells with disrupted cytoplasm, bare nuclei, may look neoplastic but can be ignored
  • Nuclei enlarged, chromatin coarse, nucleoli may become visible
87
Q

What are the main causes of acute inflammatory lumps?

A
  • Bacterial infection
  • Foreign body
  • Trauma
  • Tumour necrosis
88
Q

What are the cytological diagnoses of inflammatory lesions?

A
  • Septic inflammation
  • Pyogranulomatous inflammation
  • Steatitis/panniculitis
  • Granulomatous inflammation
  • Eosinophilic inflammation
89
Q

Describe the common cytological appearance of acute inflammation

A

Suppurative and neutrophilic

90
Q

What features indicate infection on cytology of a cutaneous lump?

A
  • Marked inflammatory response
  • Bacteria in neutrophils, or degenerate neutrophils
  • Single population of bacteria
91
Q

What features indicate contamination, rather than infection, on cytology of a cutaneous lump?

A
  • No inflammation
  • Mixed population of bacteria
  • Bacteria not within neutrophils
92
Q

Describe the features that indicate neutrophils are degenerate

A
  • Karyolysis (nuclear swelling)
  • Pale staining
  • Ragged outline
  • “Fluffy” appearance
93
Q

Describe the appearance of non-degenerate, normal neutrophils

A
  • Similar to those in circulation

- Hypersegmentation followed by pyknosis is the normal pattern of degeneration of neutrophils

94
Q

Describe the key cytological features of benign tumours

A
  • Small, siimilar sized cells, 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
  • Exception is lymphoid tumours
95
Q

List the subclasses of criteria of malignancy

A
  • Abnormal cell location
  • Architectural criteria
  • Cell features
  • Nuclear features
  • Cytoplasmic features
96
Q

Describe the location criteria of malignancy

A

Abnormal location e.g. lymphocytes found in skin sample

97
Q

Describe the architectural criteria of malignancy

A
  • Haphazard cell arrangement
  • Loss of cohesion (caused by downregulation of adhesion molecules)
  • Loss of contact inhibition
98
Q

What does the loss of cohesion in malignant tumours mean for sampling?

A
  • Loss of cohesion means increased exfoliation

- Often leads to a hypercellular sample

99
Q

Describe the cell features of malignancy

A
  • Macrocytosis: large cells
  • Anisocytosis: variation in cell size (3-4x)
  • Find cell of abnormal cell type with smallest size, find biggest, estimate how many times smallest fits into biggest
  • ## Normal is 1-1.25x difference, any larger indicates malignancy
100
Q

Describe the nuclear criteria of malignancy

A
  • Anisokaryosis: vaariation 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 Nuclear:Cytoplasmic ratio