SA solid tumour 2 - oral & mammary tumours

List the clinical signs of an oral tumour

(tumour more common in dogs cf to cats)

• Mass / facial swelling

• Oral bleeding

• Dysphagia / pain

• Halitosis

• Epistaxis

• Loose teeth / proliferative lesions noted @ dentals (always biopsy)

• Cervical lymphadenopathy

What are the three most common oral tumours in a dog?

• Malignant melanoma

• SCC

• Fibrosarcoma

(acanthomatous ameloblastoma most common benign)

(In order of frequency^)

How do you diagnose an oral tumour?

• Assess under GA

• Biopsy (incisional wedge)/ (FNA)

How can you stage an oral tumour?

• Visual assessment usually underestimates quantity of 1° tumours as locally invasive

• Rads = insensitive so use advanced imaging —> CT

Why should you assess in the LNs in a tumour case? How should you assess the LNs for metastatic tumours?

• Palpable normal LN can contain tumour esp melanoma

• Enlarged LN are not alwyas metastatic

For all metastatic tumours

• FNA submandibular nodes

• Image retropharyngeal nodes & sample if poss

• If CT available consider lymphangiography

How do you assess for metastases?

• Likelihood of distant metastases depends on tumour type

• Rads —> 2 laterals & 1 DV (inflated)

• + Abd imaging for melanoma

• (CT has greater sensitivity)

What is the tx of choice for an oral tumour?

• Surgery

  • Maxillectomy / mandibulectomy

  • Margins dictated by histology

(For FSA & SCC follow w/ adjuvant radiotherapy for better results)

• Palliative radiotherapy alone when surgical excision not poss

What margins do you use for

• Acanthamous ameloblastoma

• Squamous cell carcinoma

• Fibrosarcoma

Acanthamous ameloblastoma = 1cm+

Squamous cell carcinoma = 2cm+

Fibrosarcoma = 3-5cm+

What are the complications of oral surgery for the treatment of oral tumours?

• Recurrence

• Dogs generally adapt very well, cat more variable (may need feeding tube)

  • Bleeding

  • Infection

  • Altered cosmetic appearance

  • Difficulty prehending food / messy eating

  • Salivation

  • Mandibular drift esp in cats (see below)

    • due to lack of structural support

      

What dogs are more likely to get oral melanoma?

• Generally smaller dog

• Older (mean 11.4yo)

• Golden retriever, cocker spaniel, min poodle, chow chow predisp

What are the features of an oral melanoma?

• Very locally invasive

• Highly metastatic (check both submand LNs, regardless of location in mouth)

How is melanoma diagnosed? What are some prognostic indicators?

Based upon melanin containing mesenchymal cells

• Some tumours do not contain melanin

  • IHC required for diag

• Mitotic index useful for predicting outcome

• Size & stage significant for survival

  • <2cm + no metastasis = longer survival time than >2cm or LN metastasis

How is an oral melanoma treated?

• Surgery —> ass. w/ high rates of recurrence

• Radiation therapy —> as primary or adjunctive therapy

What can be used as antimetastatic treatment for oral melanoma?

(chemo does not meaningfully extend survival)

• Plasmid vaccine immunotherapy —> use in stage II & III dx

  • targets melano-protein —> tyrosinase

    • stimulates immune response that affects canine tyrosinase expressing cells —> melanocyts

  • Probably only helps minority but only minor local side effects (£££)

Does SCC have a higher or lower metastatic rate cf to melanoma?

• Lower (but note tonsillar SCC has a >70% metastatic rate)

How do you treat oral SCC?

• Local control = mainstay

• Surgery

• Radiotherapy

• Medical therapy (when other therapies aren't possible)

  • Piroxicam

  • Piroxicam + Carboplatin

  • Meloxicam often used

What is the clinical presentation of a tonsillar SCC?

• Dysphagia, coughing

• Enlarged cervical LNs —> abcessation

• Enlargement of 1 or both tonsils on clin exam

high metastatic rate

How is a tonsillar SCC treated?

• Local control of tonsillar enlargement —> surgery or radiotherapy

• Surgery or radiotherapy for LN metastasis

• Carboplatin / mitoxantrone chemotherapy might be beneficial

What is the prognosis for tonsillar SCC?

Median survival time = 7 months

• patients that receive most therapy live longest

• control of local / regional dx most imporant

What are the features of an oral fibrosarcoma?

• Large breed dogs especially Golden Ret & Labrador

• Middle age dog —> median age approx 7.5yrs

• Invasive

• Low / moderate metastatic risk —> lung & occ. LNs

How do you treat a fibrosarcoma?

• Local control = mainstay but challening

  • Surgery (most important) but relatively high recurrence rate

  • Additional radiotherapy often best

    • multimodal i.e. surgery + radiotherpy = higher median survival time & lower recurrence rate

• Size = prognostic indicator

  • smaller tumours = better outcomes

How do histologically low-grade, biologically high-grade fibrosarcoma present?

• Often cd maxilla

• Aggressive, rapidly progressing oral tumour w/ benign histological appearance even after large biopsy

• Very locally invasive

  • aggressive local management w/ surgery & radiotherapy tx

What are the features of epulides? Give some examples and their differences

Non-metastatic lesions arising from gingiva

• Acanthomatous ameloblastoma (most common)

  • Agressive local behaviour & bone invasion

• Peripheral ondotogenic fibroma

  • Slow growing, firm masses, usually non invasive

What are the features of canine oral osteosarcoma?

• Aggressive

• Not as rapidly metastatic as appendicular

• Site & histological grade prognostic

  • survival —> mandib > maxill

    • maxil = die of recurrence

    • mandib = die of metastases

  • local recurrence high so complete excision vital

    • palliative radiotherapy if unresectable

List the uncommon oral tumours of the dog

• Extramedullary oral plasmacytoma

• Oral lymphoma —> form of epitheliotrophic

  • requires multiagent chemo

• Undifferentiated tumour of young dogs

  • rare —> grave prog

What is the most common feline oral tumour?

SCC

What incr the risk of feline oral SCC?

• use of flea collars

• exposure to smoking

• canned food including canned tuna.

How do feline oral squamous SCC present?

• Anorexia due to discomfort

• Locally invasive

  • Low metastatic risk

  • Higher metastatic risk in cd positioned lesions

• Anywhere in mouth but predilection base of tongue

  • bone invasive

How does the outcome in feline oral squamous cell carcinoma differ?

• Cats w/ surgically resectable dx can have good outcome but recurrence common

• Best outcome in rostral mandib SCC

• Soft tissue lesions affecting tongue have poor prog as resections difficult

How do you treat a feline oral SCC?

• Surgery (depending on position)

• Long term feeding tube often needed for several months

• Radiotherapy occ helpful

What are the features of feline fibrosarcoma?

• Middle aged or older

• Very locally invasive

• Tx = surgery

  • good outcomes poss w/ mandibulectomy; maxillaectomy more difficult

What oral lesion is being shown in this CT?

Multilobular osteochondrosarcoma —> dogs

• Popcorn appearance radiographically

• Usually a local problem

• Resectability & grade predict survival

What oral lesion if being shown here?

Viral papillomatosis —> dogs

• Wart like lesions affecting oral soft tissues

• Usually resolve in 4-8 wks

• Occasionally persist in immunosuppressed animals

What breeds do eosinophilic granulomas affect?

Husky & CKCS

How is eosinophilic granuloma managed / treated in dogs

Surgery & corticosteroids

Where do eosinophilic granulomas usually affect dogs vs cats?

Dogs —> ventral & lateral aspect of tongue

Cats —> typically errosive lesions affecting upper lip near midline

What are the features of transmissible venereal tumours in dogs?

• Prolif lesion affecting dogs who have been licking places they shouldn’t while on holiday in southern europe

• Spontaneous regression & v. responsive to vincristine

What are the risk factors of mammary tumours?

• Hormone exposure

  • (Balance early neutering risk against risk of urinary incontinence)

  • progestin, oestrogen use can incr risk

• Obesity —> can incr oestrogen levels

  • being underweight @ puberty = reduced risk

• Age —> older cats & dogs

  • usually always malig in cats

• Breed

  • Poodles, Chihuahua, dachshund, Maltese, cocker spaniel and Yorkshire Terrier

  • Siamese cats

How do you diagnose a mammary tumour?

• Palpation

  • clinical exam —> tumours >3cm have poorer outcome

  • fixed tumours

  • palpably enlarged LNs

• Excisional biopsy by single or segmental masectomy

• FNA can be used to exclude other ddx (e.g.- mastitis, lipoma or mast cell tumour, hyperplasia) not for diagnosis

How can you locally stage a canine mammary tumour?

Assess local LN & typical drainage patterns:

• 1 and 2 will go to axilla

• 4,5 and sometimes 3 will go to inguinal node

How are mammary tumours distantly staged?

• Thoracic rads / CT

• Abdo U/S —> visceral metastases

  • can also metastasise to bone —> consider bone pain

How do we treat canine mammary tumours?

• Low risk —> single masectomy

• High risk —> consider regional masectomy

• Intact bitches —> consider unilateral chain masectomy due to recurrence risk

What are the excision margine for canine mammary tumour margins?

• Mobile lesions —> whole gland removal

• Fixed lesions —> 2cm margine & removal of affected abdo fascia / wall

  • if neutering do this first if poss

List the post surgical prognostic factors of a mammary tumour

• Tumour type

  • Malignancy

  • Less tissue heterogeneity ass. w/ poorer outcome

  • Sarcoma (esp osteosarcoma) poorer than carcinoma

  • Mitotic rate /Ki-67

  • Grade

  • Hormone receptor expression —> lack of expression correlate w/ poorer outcome

What are the features of a canine inflammatory carcinoma?

• Extremely painful

  • Easily mistaken for mastitis

• Generally all glands affected

• FNA = inflam cells & tumour cells

What is the prognosis of Canine inflammatory carcinoma

Very poor

• Excision not typically feasible —> recurrence v. common

• Palliative tx

  • Medical therapy might prolong survival for a few months

What is the big difference between canine and feline mammary tumours?

• 85-95% feline mammary tumours are malignant (cf to 50ish% in dog)

What is a significant differential for feline mammary tumours?

fibroepithelial hyperplasia (usually all glands are enlarged)

What are the clinical prognostic facotrs for feline mammary tumours?

• Size

  • >2cm = significantly less survival time than <2cm

• LN metastasis

  • lymphatic drainage less predictable than dogs

  • assess inguinal & axillary nodes bilaterally

• Distant metastasis

• Breed

  • DSH = better outcome

How are feline mammary tumours treated?

• Chaine masectomy preferred to single / regional masectomy

• Surgical resect inguinal and/or axillary LNs for high risk tumours

Should you perform an ovarihysterectomy @ time of mammary tumour excision?

• Dog —> for benign tumours beneficial

  • Less clear for carcinoma

• Benefit in cats has not been evaluated