Derm Oncology 1

Know and understand the behaviour most common skin and subcutaneous tumour types • Understand the clinical effects of cutaneous and subcutaneous tumours • Describe general approach including staging, treatment, and prognosis (particularly mast cell tumours)

tumour in dogs3

• most common species to have tumour

• 1/3 of all neoplasm

• most is benign (60-80%)

tumour in cats 3

• 2nd most common species to have tumour

• ¼ of all neoplasm

• most is malignant (65%)

primary or metastasis common in cutaneous tumour?

• name 2 presentation associated with metastasis

mostly primary

but occasionally metastatitc leision

• multiple cutaneous metastasis

• lung-digit syndrome

  • digital and cutaneous metastasis

  • associated with lung cancer in cats

how are cutaneous tumour classified 3

• Tissue of origin (epithelial, mesenchymal, vascular)

• Cell of origin if possible (e.g. mast cell tumour, lmyphoma, histiocyte or melanocyte)

• According to degree of malignancy

also look at the table in notes

see notes

most common skin tour in dog and cat

name top 3

dog

• MCT, lipoms, hisyiocytoma

cat

• basal cell tumour, mast cell tumor, SCC

cause of cutaneous/ subcutaneous tumour 6

• UV radiation (esp sun and UVB—> SCC)

• Chemical carcinogens

• Irradiation

• Physical agents + damage

• Viruses (e.g. papillomas)

• Inflammation (e.g. implicated in FISS)

during examination,

• feature suggesting malignency 6

• to consider 2

• Rapid growth

• Fixation

• Invasion into overlying skin or deep tissues

• Ulceration

• Poorly defined margins

not all aggressive lesions show these features.

• pseudocapsule formation: sarcomas seem well demarcated

• Mast cell tumour can mimic lipoma (soft cutaneous or subcutaneous masses)

approach to diagnosing cutaneous/ subcutaneous tumour

FNA, cytology, biopsy

name FNA good and bad

• useful for

• when do you skip NFA and skip to biopsy

• what else to do after FNA: gold standard

• cutaneous and subcutaneous mass lesions

• Superficial, ulcerated, very inflamed—> biopsy

• Histology gold standard – Submit after resection

cytology

• used for differentaiting 2 and can provide 1

• note if inflammation is marked

• neoplastic from inflammatory

• malignant from benign

cells surrounded by inflammatory cells show changes impersonating malignancy

• dysplastic vs neoplastic change

biopsy types and which one better

Small punch needle

• may not be representative

Incisional biopsy (wedge)

• good sample for histology

ncisional biopsy removes a portion of tumour for diagnostic purposes

• The golden rules of incisional biopsy:7

• Plan biopsy site

• Sample selection: representative part of the lesion

  • Avoid major structures

  • Avoid necrotic, haemorrhagic or infected areas

• Incision position

  • entire biopsy tract can be removed during subsequent sx

• large incision

  • harvest without xs tissue manipulation

• Minimise instrumental manipulation

  • Avoid diathermy, cryosurgery etc.

• Include a portion of normal tissue only if easy to do

• Ensure adequate fixation

Excisional biopsy widely used in skin tumor removal, then submission for histology.

• indication 3

• benign proliferative epithelial tumours

• highly likelihood clinical diagnosis is correct + minimal margins required

• knowledge of histogenesis of the mass will not change surgical dose

Clinical contraindications for excisional biopsy for cutaneous and subcutaneous masses 8

• Rapidly growing mass

• Ill-defined or poorly demarcated lesion

• invaginate to underlying and overlying tissue

• Peritumour oedema or erythema

• ulceration

• FISS

• prev. FNA suspicious for MCT or STS

  • nost undiag —> sarcoma.

• Non-diagnostic FNA

Staging of skin tumour 4

• name what/ why would you do it

• Proper recording of the primary mass

  • Measure tumour

  • photograph

  • identify the locationon body map

• diagnose tumour via FNA, cytology, biopsy

• FNA and examination of nodes

  • if enlarged

  • if suspicious or known malignant tumour/ MCT

Further diagnostics

• indicated depending on pathology of lesion and evaluation

General treatment options for skin tumours

• treatment of choice?

• wb huge tumours? what if it is on extremety

• incompletely excised tumour

• name other treatment modality 4

Complete surgical excision is standard of care

• Cytoreductive surgery; Amputation if on extremities

• Radiation therapy for incompletely excised tumours

• photodynamic therapy, cryosurgery, laser ablation and hyperthermia

epithelial tumours: name 6 possible epithelial cell ddx

• most common?

• Squamous cell carcinoma

• Basal cell carcinoma

• Perianal gland carcinoma

• Sebaceous gland tumour

• Sweat gland tumour

• Tumours of hair follicles

what is SCC ?

• prevalnece in cat ad dog

• behaviour 1

• in which site is SCC commonly seen in both cats and dogs?

Malignant tumour of squamous epithelium

• 15% of feline and 5% of canine cutaneous tumours

• behaviour varies with site and species.

• SCC is an important tumour in oral cavity of cat and dog.

canine papilloma

• common in

• caused by

• progression 2

• care with papilloma px

Young dogs

• Viral (DNA papillomavirus)

• Usually regress,but possible malignant transformation to SCC

usually immunosuppressed

feline SCC: prevalence

• more common in

• affected area

• singl/ multiple leision?

• older animals (median age 10–12 years)

• nasal planum, pinnae, eyelids, and other head and neck sites.

• 30% multiple lesions at presentation

feline SCC: cause

• what sepcial feature may cause hgiher SCC risk

caused by UV exposure from sunlight (UVB)

• white hair coat 13x the risk of non-white cats : melanin protection

three stages in feline SCC development, give simple description

referring to the picutre

Actinic keratosis (a)

• pre-cancerous

• dysplasia due to chronic UV exposure

Carcinoma in situ (b)

• have not penetrated basement membrane

Invasive SCC (c)

• penetration of basement membrane

feline scc appearance and clinical presentation

• appearance 4

• any paraneoplastic syndrome?

variable appearance

• plaque like

• crusting and ulceration common

• ucerated, crateriform or fungiform

• associated fibrous tissue—> indurated (thickened or hardened)

hypercalcaemia rarely

feline SCC diagnosis

• wich diagnostic method is preferrred?

• what do you do if there is multiple affected area? what do you have to keep in mind when submitting sample?

• FNA is unreliable, incisional biopsy is recommended

• often multiple abnormal areas —sample all

  • some areas will be dysplastic/AK; others overt SCC.

  • label all the samples!

feline SCC: metastatic potential

• metastasis ssociated with

• name 2 location

associated with advanced disease

• locoregional nodes first

• progress to pulmonary metastases

feline SCC tx option 6

• best approach other than early detectio

• list the 2 type of radiotherapy

1. Surgical excision

2. Radiotherapy

   • direct beta radiation (strontium 90) control carcinoma insitu

   • external beam (orthovoltage) in early stage local control

3. Photodynamic therapy

4. Intralesional chemotherapy

5. Electrochemotherapy

6. Topical imiquimod

Surgery:

• what approach gives the best long-term control?

• ear, nose, eyelid,

Wide surgical excision provides long term control: Pinnectomy, nosectomy etc

• Pinnectomy— >1.5 years tumour control

• nasal planum tumour —> good local control, but must achieve margins (refer)

• Enbloc resection of lower eyelid tumours —> good control (refer)

most successful in smaller tumour

Feline SCC: Radiotherapy:

what is the 2 type of radiotherpay

• name what kind of tumour you would use this on

• name 1 feature of orthovoltage

• name 3 advantage of strontium 90 plesiotherapy

external beam (teletherapy) or direct beam (brachytherapy)

external beam— orthovoltage

• superficial, exophytic tumour <2cm

• satge T1 better outcome than that of T3

Direct beam— strontium 90 plesiotherapy

• supercifial SCC (<2mm in depth)

• carcinoma insitu control, sparing of local normal tissue, repeatable

Feline SCC: Photodynamic therapy

• what is it how do you do this?

• what are the considerations if outdoor cat?

• what kind of tumour does this work on

  • how long does it control?

Local or systemic administration of photosensitiser

• Administration of light (appropriate wavelength) to activate the drug several hours later

• reasonably well tolerated

  • Local adverse effects

  • keep cat away from bright light and indoors for two weeks

Small, non-invasive, early stage tumours only : control 5-35 months

Feline SCC: Photodynamic therapy

• advantage 4

• Non-invasive

• does not require multiple GAs

• Reasonable results with good case selection

• can be repeated

Electrochemotherapy: feline scc

• how is this achieved?

• response rate? remission?

• concern?

• Intralesional or systemic bleomycin (good response rates)

• High response rates but variable duration

  • depending on lcoation

  • priocular/ heaad and neck> nasal planum> cutneous

• Possible significant local side effects

Feline SCC: cryotheraoy and carboplatin

• cryo: what tumour can u use it on)

• cryo response rate?

• carboplantin response rate?

  • concern— hwy we dont use it

Cryotherapy

[Small (<2cm, superficial) tumours only]

• Aggressive—>good local control of pinnae and eyelid.

• nasal planum poorer response. o

Intralesional carboplatin

• 73% CR, 55% progression free @ 1y

• Safety: major concern!

Prevention of feline SCC 3

• name 1 approch that does not work

• high riskers should avoid sunlight at height of day

• UV light-blocking film for windows

• outdoor cats: sunblock

  • avoid ingestion •

  • impossible to administer to the nasal planum without being licked off.

Tattooing does not decrease the incidence of SCC

name a form of cutaneous in-situ carcinoma (basement intact)

• presenation 1

• treatment of choice 1

• name one pother treatment

  • what is its activity 3

  • name 5 side effects

Bowenoid carcinoma in situ

• multiple sites

• Surgery treatment of choice

• Imiquimod cream (aldara)

  • immunomodulator with antitumour and antiviral effects

  • local erythema, increased liver enzymes and neutropenia, hyporexia and vomiting

Canine SCC

• prevalence

• most common site3

• association/ predisposing factor of sites 2

older dogs, median age 10–12 years

The most common sites and association

• Nasal planum—(inflmamation?)

• Nailbed (subungual)— large breed, dark hair coat

• Ventrum — UV exposure

canine SCC: nasal planum presenation

• treatment of choice

• what about radiotherapy?

• what if the owner does not want to do sx, and want to opt for short term palliative care?

• prognosis?

More difficult to manage than in cats

• Aggressive resection

• poorly radiosensitive

• combination of radiotherapy and intralesional chemotherapy

poor prognosis :(

canine Subungual SCC

• why is staging important when you see subungual scc in dog

• tx

• what if it comes back after eh tx?

• to rule out lymph node metastasis (common)

Treatment: sx, no adj therapy needed

• ampute affected digit at the level of the MC/P, MT/P, or proximal IP level

• limb amputation

melanocytic tumours arise from melanocyte at? 4

anywhere but most comonly

• basal layer of the epidermis: cutaneous or dermal melanoma

• epithelium of the gingiva: oral melanoma

• nail bed: digital melanoma

• ocular structures: iris etc

melanocytic tumour Predisposed breeds include 5

• Standard and Miniature Schnauzers

• Doberman

• Scottish Terrier

• Irish and Gordon Setters

• Golden Retrievers

melacytoma vs melanoma

• what is the main difference that inidcate malignancy of melanoma?

Benign – melanocytoma

• hairy skin

Malignant – melanoma

• oral, digital, subungual

Cutaneous/nailbed melanoma

• malignant melanoma can be _____

• spreading route: 2

• early metastasis can be seen at

• Malignant tumours may be AMELANOTIC

• lymphatic and haematogenous routes.

• regional LN or distant metastases—> staging!

Approach to melanocytic tumours— work up 3

1. History and clinical examination

2. Fine needle aspiration or biopsy

3. Staging (regional LNs, lungs +/- visceral organs)

Approach to melanocytic tumours— tx for benign cutaneous leision

Benign cutaneous lesions

(pigmented, located on haired skin, <2 cm in diameter, mitotic rate < 3/10 HPF)

• complete excision surgery is curative

Approach to melanocytic tumours— tx for primary malignant tumour

Primary malignant tumours

• removal of LN

• complete radical surgical excision

  • margins of up to 3cm necessary

Nail Bed/ digital melanoma: Treatment

• what is the standard treatemnt

• what about radiotherapy

• what else would you do other than sx?why? ( esp dog oral melanoma)

sx: amputation of the affected digit

• all 3 phalanges to ensure adequate surgical margin

• Limb amputation may be necessary to achieve an adequate margin

• Draining lymph node(s) removed at the same time

radiotherapy

Sensitive to RT but irradiation of foot is challenging (toxicity to pads)

immunotherpy: delay/ prevent metastasis

• tyrosinase – involved in melanin biosynthesis

• intradermal vaccine

• safe in cutaneous and nailbed tumours, but of unknown efficacy.

Feline cutaneous melanoma

• malignancy compared to ocular or oral melanoma

• treatment/ management?

Cutaneous melanoma uncommon

• Less malignant than ocular or oral

• Surgical management

Soft tissue sarcomas

• malignancy/ aggressiveness?

• how do you confirm behaviour?

• LN metastasis?

Infiltrative and locally aggressive

• sx—> histopath to confirm complete excition and grade

  • predicts behaviors

Nodal metastases uncommon

decision tree for STS

see notes

Feline Injection Site Sarcoma is associated with vaccine/ inflammation.

• describe FISS

• name a few vaccine 2

• comon origin? name most comon type

• characterised by____

• recurrence rate?

• how do you determine chances of metastatis?

chronic inflammation in a genetically predisposed cat

• Rabies, FeLV vaccines

• mesenchymal in origin – fibrosarcoma

• Characterised by very aggressive local behaviour

• High recurrence rates

• 10-20% meatstasis overall; 40-50% if histologically high grade

FISS latency period for tumour development

a few months to several year

Recommendations for vaccination: to avoid FISS 4

• Avoid vaccinations in the interscapular space

• Subcutaneous rather than intramuscular

• Rabies/FeLV vaccines on the distal aspect of the right (rabies) and left (FeLV) pelvic limbs

• vaccine only after strong consideration of patient’s exposure risk

Approach to Suspected FISS

• 2 approaches to investigate fiss

• name 2 disadvantage to FNA

• incisional/ excisional biopsy?

• wha would you do for sx plannign

1. Examination

firm cutaneous or subcutaneous mass

2. 3-2-1 rule for investigation

• present 3 months or longer

• greater than 2 cm diameter

• continues to increase in size 1 month posst injection

FNA: may not be diagnostic

• Inflammatory component may be harvested

• Sarcoma component may not exfoliate well

Incisional biopsy preferred

• Excisional biopsy guarantees treatment failure

  • recurrence 66days,

  • extend tumor bed every resection

to plan sx: complete staging involving advanced imaging

flowchart to FISS

Tx selection for local/ locoregional therapy

• main challnege

• main modalities 2

• what else can be used post-op for local immmunotherapy?

• Local disease control is the main challenge

• surgery and radiotherapy are the main modalitie

• Infiltration of IL-2 (local immunotherapy).

Tx selection for systemic therapy: FISS

• role of post op chemotherpay 3

• how else can u use chemo

role of medx is limites

• post-operative chemotherapy in high grade tumour—uncertain.

• Metronomic chemotherapy used instead of radiotherapy (but unproven) or in multimodal approach

FISS: sx

• concerns

• to do this properly

• high recurrence rates, 66days

  • increase per repeat surgeries

  • greater if histologically margins unclear

• RADICAL + 3 to 5 cm margins

  • normal tissue

  • multiple tissue planes, body wall

  • ostectomy as indicated.

FISS: Radiotherapy

• mainly used pre/ post ogg?

• benifits pf radiotherapy

• problem w post op radiation? 5

• what couls improve survival but done less?

pre-op or post-operatively

• benefit in delaying or preventing recurrence and increasing survival times

Problem with post-op radiation?

• Not knowing where tumour was

• Long and complex scars

• post-op tissue migration (use surgical clips!)

• Unable to identify microscopic disease in the gross cat

• Important structures deep to tumour bed

Pre-operative radiation followed by radical surgical excision +/- post operative radiation

Round Cell Tumours of the Skin and Subcutis 3

• Histiocytic tumours

• Mast cell tumours

• Lymphoma

Histiocytic skin leisions include:

• list 3, from most benign to most malignant

• and say what celll origin

give one extra one for extra point

Canine cutaneous histiocytoma

• Arise from epidermal Langerhan dendritic cell – Benign

Reactive histiocytosis (cutaneous or systemic)

• Arises from activated interstitial dendritic cell

Cutaneous involvement: histiocytic sarcoma

• Arises from interstitial dendritic cell

(Haemophagocytic histiocytic sarcoma

• macrophage lineage cell)

Canine cutaneous histiocytoma

• prevelaence, age at pfresentation

• breed predispose 4

• 14% of all skin tumours, young dogs (<3 years) mostly

• Boxers, dachshunds, cocker spaniels and bull terriers

Canine cutaneous histiocytoma

• clin presentation

• progression

• diagnostic— what do you expect to see

• treatment of choice? if that doesnt work?

presentation:

• raised, often hairless lesions

• may grow rapidly

• Cytology usually diagnostic,— pleomorphic round cells with a lymphoid infiltrate

• may regress spontaneously

  • but if not, surgical excision and submit mass for histology.

Lipoma

• 2 situation when it is a concern

• what malignancy can this be mixed up with? what makes it difficult to diff?

Benign tumour of adipocytes

• infiltrating+ attach to muscle

  —>Recurrence

Remember LIPOSARCOMA

• hard to dx as dissolve in fixative

• both fatty adipocytes look similar