Oncology: Thoracic tumors, OSA, urogenital, sarcomas, and MCTs (E2) Flashcards
What is most commonly the presenting complaint with chest wall tumors? What is the typical signalment?
Owners notice a firm and fixed thoracic wall mass
Middle aged large dogs
What is the most common chest wall tumor? 2nd most common?
OSA
CSA
How do you work up and stage a chest wall tumor?
- Rads
- Cytology to diagnose it as a sarcoma
-
Open (wedge) biopsy for subtype of sarcoma *SUPER IMPORTANT*
Large biospy from center of field, minimize hemorrhage - CT for surgical planning
What form of chest wall tumor is often misdiagnosed as a chondrosarcoma and why is this misdiagnosis particularly problematic?
Chondroblastic OSA
Very very aggressvie tumor
How do you treat chest wall tumors? How many ribs can you remove, at most? When would you perform a diaphragmatic advancement? What can you use to help close large defects following ressection?
En bloc exision w/chest wall reconstruction
Max 6 ribs
If the mass is located in the caudal thorax
Prosthetic mesh augementation
For what type of chest wall tumor is adjuctive chemo recommended?
OSA
(not with CSA)
While a 3cm skin margin is not required for chest wall tumors, where is it important to get margins?
Around biopsy tract
What must you place before completing reconstruction after removing a chest wall tumor?
Place a thoracic tube
Is the MST longer for chest wall OSA or CSA?
CSA
(299-1080d vs 129-249d (depending on if doing chemo for OSA or not)
What unique comorbidity occurs in cats with lung tumors?
Lung-Digit Syndrome (mets to weight-bearing digits and 3rd phalanx) - Lameness
What is the most common lung tumor in dogs and cats and how are these tumors classified? Which subtype is more common in dogs? Cats?
Carcinomas (ACA)
By location
Dogs: Bronchoalceolar
Cats: Bronchial (larger airways)
What staging method for lung tumors should be done with US guidance and under sedation? What is an essential tool for staging and why?
Transthoacic FNA/cytology
CT = essential because if metastasis to LN has occured the prognosis is poor
Why should you never amputate a cats digits without first taking chest rads?
Because the tumors on the digits are mets from a primary lung tumor, removing the toes will not prolong survival nor will removing any lung because this presentation indicates advanced disease
What are the 5 prognostic variable for lung tumors in dogs?
Tumor size (smaller=better)
Location (more peripheral=better)
Presence of CS (coughing=worse)
Clinical change (mets=worse)
Histologic score (vascular/lymphatic invasion=worse)**POST-OP DETERMINATION*
What is the diference in MST in a cat with a poorly differentiated vs a well differentiated lung tumor? The presence of what is also a negative factor?
Poorly=2.5 mo
Well=23 mo
Pleural effusion
What breeds are predisposed to histocytic sarcoma?
Bernese mountain dogs
Flat-coated retreiver
A 10 year old cat presents with a mediastinal tumor as well as edema around the head, neck and forelimbs. What does this cat have and what caused it?
Caval syndrome
Tumor invasion into the cranial vena cava
What are the 2 most common cranial mediastinal tumors?
LSA
Thymoma
A dog that has a cranial mediastinal mass and megaesophagus probably has a ______.
Thymoma
What will a cytology of a thymoma reveal? What can be done to differentiate thymic lymphocytes from lymphoma?
Neoplastic epithelial cells with large numbers of small mature lymphocytes as well as intermittent mast cells
Flow cytometry
How are thymomas classified? Which is more common in cats? What is the treatment (include any meds)?
As invasive or non-invasive
Cats: Non-invasive (50-100%)
Surgery= Gold standard treatment
Cats should always get steroids
Is the prognosis better for dogs or cats with thymoma?
Cats (MST 1825d vs 790d)
What are the 3 poor prognostic factors for dogs with thymoma?
Young age
Megaesophagus
Histologic subtype (Lymphocyte rich variant better)
What is the most common primary bone tumor in dogs and cats? Which species is affected more commonly and where do they tend to form?
OSA
Dogs
Appendicular skeleton
What is the typical signalment for OSA in dogs?
Neutered male large to giant breed (Rottweiler, Great dane, Scottish deerhounds) either 1-2yrs old or 7-9yrs old.
What are your top differentials for primary bone tumors in dogs?
OSA
CSA
FSA
HSA
If a dog presents with systemic illness and a mass that looks a lot like an OSA, what else could it be (other than a tumor)?
Infectious fungal disease: Valley Fever (Coccidiodes immitis), Blastomyces dermatitis
What is the most common location for an OSA to form? 2nd most common?
Distal radius
Proximal humurus
Away from the elbow, toward the knee
What are the 3 basic types of OSA? Which is most common?
Endosteal (most common)
Periosteal
Parosteal
What diagnostics should you perform for OSA?
CBC/Chem - Increased ALP is bad
Thoracic met check or CT met check
Localized imaging
Nuclear scintigraphy (gold standard) or full body rads
What is the typical radiographic appearance of OSA?
A mix of lytic and blastic pattern
Loss of cortical bone
Periosteal proliferation
Palisading coritical bone (sunburst effect)
Codman’s triangle (periosteal lifting caused by subperiosteal hemorrhage)
Loss of fine trabecular pattern in metaphyseal bone
Pathologic fractures with metaphyseal collapse
Why does OSA not cross joints?
Cartilage provides a barrier due to collagenase inhibitors (may inhibit tumor cell invasion or neoangiogenesis)
How can OSA be diagnosed?
FNA/cytology (into medullary cavity) *PREFERRED*
Bone biopsy- Jam Shedi (small diameter, gold standard) or Michele trephine (large core, more risk)
What is the gold standard for locally controling primary bone tumors? What do you need to do if you have a proximal femoral lesion?
Limb amputation
(Thoracic- Forequarter technique
Pelvic - Coxofemoral disarticulation)
Must be more aggressive w/surgery and do en-bloc acetabulectomy or subtotal hemipelvectomy
What is the most common reason for performing limb-sparing procedures for bone tumors?
Owner reluctance
What are the contraindications for limb salvage procedures with bone tumors?
Large lesion (>50% diaphysis involved)
Extensive soft tissue involvement
Pathologic fracture
Poor owner compliance
Advanced disease
Inappropriate location of tumor
At what sites is limb salvage surgery the primary mode of therapy? What are common complications and what’s the silver-lining for one of these ?
Distal radius
Distal ulna (gold standard in this location)
Digit or metacarpus/tarsus
Scapula
Complications: Implant failure, infection (silver lining is tat those that get infections survive longer than those who do not)
What is the minimum aount of radiation a bone tumor needs to get when doing SRS?
35 Gy
What is the best site for SRS based on low post-op fracture rates?
Proximal humerus
T/F: Adjunctive chemo is recommended in all cases of canine OSA.
True
What is the go to choice for adjunctive chemo for OSA in dogs?
Carboplatin
What are aminobisphosphonates? Why are they used? Name 2 drugs in this class.
Palliative therapeutic option for OSA that ingibits osteoclastic bone resorption
Zoledronate (IV)
Pamidronate (IV)
Is radiation a good palliative therapeutic option for a dog with OSA? Why or why not?
Yes, reduces local inflammation, minimizes pain, slowes progression of mets and improves QOL.
What is the prognosis for a dog with OSA with palliative therapy alone? Surgery alone? Surgery or SRS with chemo?
P: 1-3 mo (‘P’ rhymes with ‘one to three’)
S: 4-6 mo
S+C: 8-12 mo (double S alone)
What are prognostic indicators for dogs with OSA?
Body weight (smaller/lighter=better)
Age (older=better)
Site (prox humerus= worse)
Volume (larger-worse)
Histologic grade
Alkaline phosphate (every 100 I/L increase = 25% increase in risk of death)
What are the prediliction sites for feline OSA? Is it more or less aggressive than in dogs? What is the standard of care and the MST?
Distal femur
Proximal tibia
Proximal humerus
(Elbow, Shoulder, Knee)
Less aggressive in cats
Amputation without chemo - MST 24-49mo
What is the most common canine bladdeer tumor? What is the most common non-neoplastic DDx?
TCC
Polypoid cystitis (non-neoplastic)
What has been implicated in the etiology of bladder neoplasia in dogs?
Topical insecticides and heribicide exposure
Environmental pollution (city life)
Obesity (pesticides accumulate in fat)
Female gender (pee less)
Cyclophosphamide administration
Breed
What breed is the most predisposed to developing bladder neoplasia? What other breeds are predisposed. How can the risk be minimized?
Most common: Scottish Terriers
Also: WHWT, Beagle, Sheltie, Fox Terrier
Minimize risk by feeding vegetables (E.g. carrots) at least 3x per week, limit exposure to lawn chemicals and older flea/tick products
Where is the most common location for TCC development?
Trigone of bladder (urethral and prostate involvement common)
How are TCCs staged? What is the gold standard for diagnosis?
US +/- Cystography and/or tissue biopsy
Dx: Cystoscopy + biopsy
What is the preferred modality for getting a UA from a dog with TCC?
traumatic catheterization
What is the new diagnostic test developed for TCC? What does it look for and what is tested?
CADET BRAF mutation detection assay
Single mutation in BRAF gene
Urine
What is the “field effect”?
Phenomenon in dogs with TCC where the entire bladder lining is thought to undergo malignant change in response to carcinogens in urine.
It can cause local recurrence of the TCC even with complete excisions.
What can you do to improve the QOL of a dog with an obstructive carinoma of the urethra? What unpredictable side effect can occur?
Palliative stenting
Severe incontinence
What drug therapy is warrented for all dogs with TCC?
NSAID therapy (Piroxicam)
What is the most common chemo prologol for TCC?
Mitoxantrone + Piroxicam
T/F: TCC is the most common bladder tumor in both dogs and cats.
True
What is the most common tumor in female dogs?
Mammary gland tumors
What cat breeds are predisposed to mammary gland tumors?
Siamese
DSH
How are mammary tumors in siamese cats different from those in other breeds?
Younger age and higher rate of lymphatic invasion
Where does mammary neoplasia usually occur in dogs?
Mammary glands 4 and 5 (more glandular tissue)
What is the unique, aggressive variant of mammary gland tumors that occurs in dogs? What is the treatment?
Inflammatory carcinoma
Probably can’t treat, really poor prognosis
In dogs ___% of mammary gland tumros tend to be malignant, while in cats _____% tend to be malignat.
50%
85-95%
What are the most common feline mammary tumors (including subtypes)?
ACA
Tubular, papillary, solid and cribiform subtypes
What is the biggest risk factor for mammary tumors in cats?
Hormonal exposure - intact might higher
(91% risk reduction if OHE before 6mo)
How does OHE affect the risk for mammary tumors in dogs (what is the lifetime risk based on when spayed)?
OHE prior to 1st estrus = 0.5% lifetime risk
Prior to 2nd estrus= 8%
3rd= 26%
(No benefit >4y)
What is the most important prognostic indicator for mammary gladn tumors?
Size
How are mammary gland tumors treated in cats?
Single session bilateral radical mastectomy
+OHE if intact
+chemo if tumors >3cm
How are mammary gland tumors treated in dogs?
Single tumor: Simple lumpectomy or mastectomy
Mutple tumors: Regional mastectomy, Staged bilateral mastectomy
+OHE if intact
+ chemo if large tumors, LNs involved or if tumor aggressive
What is the MST for felines with mammary tumors <2cm with surgery alone? 2-3 cm? >3cm?
<2 3yrs
2-3cm 2 yrs
>/=3cm 6m
What is the most common beign vaginal tumor? Malignant?
Leiomyoma
Leiomyosarcoma
Is malignancy more likely in an intact or spayed female dog with a vaginal tumor?
Spayed
What is the treatment for benign vaginal tumors? Malignant?
Benign: conservative ressection w/laparotomy for OHE
Always spay because tend to be hormonally dependent and will otherwise recur
Malignant: Complete vulvovaginectomy and perineal urethrostomy
What is the most common tumor of male genitalia?
Testicular tumors
What are the DDx for canine testicular tumors?
Interstitial cell tumors (most common)
Seminomas (increased risk in cryptorchids)
Sertoli cell tumors (least common, often functional. increased risk in cryptorchids)
What should you do in addition to a bilateral orchiectomy in a dog with a testicular tumor? Why?
Scrotal ablasion
To get enough margins
What is the beign variant of a tumer of fibrous origin? Malignant? Where do the malignant ones tend to form?
Nodular fasciitis (Fibromatosis, Desmoid tumor) -need aggressive resection
Fibrosarcoma - skin, SQ, mouth
Where do intermuscular lipomas tend to form?
Caudal thigh between the SEMI’s
Why do infiltrative lipomas need to be treated like a malignancy even though they are benign?
Highly locally aggressive
T/F: Liposarcomas arise from malignant transformations of lipomas.
False
What malignancies arise from myoblasts or primitive mesenchymal tissue capable of differentating into striated muscle? Where are the most common places for these tumors to form?
Rhabdomyosarcoma
Tongue, Larynx, Myocardium
Why is the botryoid rabdomyosarcoma unique? Where does it form?
Occurs in young large breed dogs
Bladder
Which sarcoma presents with massive edema and lymph trasnlocation through the skin? How is it treated?
Lymphangiosarcoma
Surgery + Radiation + Doxorubicin + Toceranib
T/F: Hemangiomas may be precursors to hemangiosarcomas.
True
How are HSA’s staged? What location correlated with each stage?
According to depth of invasion
Stage 1 = Dermal (skin)
Stage 2= Hypodermal/SQ
Stage 3= Muscle
Where do cats tend to get HSA? What effect does aggresive treatment have on MST?
Solitary in dermis
Aggressive tx + sx MST = 1460d (4y)
No tx MST- 60d (2mo)
At which stage(s) is adjunctive chemo warrented for HSA? What drug is used adn what important side effects (name 3-4) does this drug have? Can you reduce these?
Stage 2 and 3
Doxorubicin
SE: GI, Tinnitus, very strong vesicant, dose-dependent CARDIOTOXICITY
Can reduce cardiac toxicity with DEXRAZOXANE
Can reduce vesicant effect by ICING the area (pea on it)
Can give GI protectants, antacids, etc. for GI effects
Due to the fact that PNST’s are slow growing and can get very large, they are often mistaken for what benign tumor?
Lipomas
What type of sarcoma has the highest mertastatic rate?
Synovial cell sarcomas
What breeds are predisposed to synovial cell sarcoma? Where do these tumors tend to form? How are these different from OSA?
Flat coated and Golden Retreivers
Large joints- stifle, elbow, shoulder
CROSSES JOINTS
What is the best treatment for synovial cell sarcoma?
Limb amputation
What PNS is associated with smooth muscle tumors, especially leiomyosarcomas of the small intestines?
Hypoglycemia
What tumor is referred to as The Great Imitator?
MCT
What is the likelihood of metastasis if a leiomyosarcoma forms in the liver?
100%
What sarcomas originate from fibroblasts and look and feel like a salivary mucocele? Where do these usually form?
Myxosarcoma
SQ on trunk or limbs
How do STS tend to metastasize (route)?
Hematogenous
What rule can you use to predict metastasis of STS’s?
Based on tumor grade: 1,2,3 -> 10, 20, 30(-50)
Grade 1 = 10% chance
Grade 2= 20% chance
Grade 3 = 30-50% chance
What steps would you take to work up a STS?
- FNA: R/O lipoma, seroma, inflammation, abscess
- If need more info or FNA equivocal: Incisional biopsy (Tru-cut or wedge if planning on doing Sx)
- Thoracic rads: for mets
- Regional imaging
- +/- CT for surgical margins or more comprehensive staging
What is the classic surveillance regiment post-op for STS patients?
Follow-up exams 1, 3, 6, 9 and 12 months post-op
Feel for localregional LN enlargement
Examine scar for tumor recurrence
Overall wellbeing (any systemic signs of recurrence?)
What margins do you need to take when excising a STS?
Wide excision: 3cm radial margins and 1 fascial plane deep (or 2 muscle planes deep if no fascia)
What can you assess to determine whether a patient with a STS on an extremity will do well with a marginal excision (rather than radical)?
What is the local recurrence rate with marginal excision?
Palpate it: tumor movability supports candidacy (because that means it is pseudo-encapsulated and not infiltrative)
10.5% local recurrence
When resection of a canine STS yields an incomplete surgical margin, how should residual microscopic disease be addressed?
2 options:
Adjunctive radiation therapy (17-30% recurrence)
Aggressive scar rividsion (15% recurrence- best)
Metronomic chemotherpy- cyclophosphamide + piroxicam (may not be beneficial)
What are the negative prognostic indicators for STS local control? What is the global recurrence rate following incomplete resection?
Large tumor size
Incomplete surgical margins
High histologic tumor grade
28%
What staging modality is counterindicated in cats with suspected injection site sarcoma?
Excisional biopsy
What is the current recommendation in surgical excision for feline injection site sarcomas?
5cm radial margins & 2 muscle planes deep
What is the most common cutaneous tumor in dogs?
MCT
Which dog breeds are prediposed to MCTs and what variant do they tend to get? Cat breeds?
Boxer, Bull Terrier, Boston Terrier, Bulldog (The “B”s)- get less aggressive variants
Siamese
(The B’s and Siamese rhyme)
Which breed has a tendency to get multiple benign MCTs? Which breed gets a highly aggressive form?
Pugs
Shar-peis
Where do cutaneous MCTs tend to form in dogs? Cats?
Dogs: Trunk, extremities
Cats: Head/neck, pinna or ear base
What is the disturbance called that is caused by MCT’s called which can lead to degranulation of mast cells, erythema and swelling, and if severe can cause anaphylaxis and hypotension? How can it (potentially) by managed?
Darier’s Sign
Longterm H1 and H2 antagonists (diphenhydramine, famotidine)
What are the intitial plasma histamine and gastrin levels (relative) in a dog with MCT? What about a dog with adequate tumor control?
High histamine, Low gastrin
Controlled= normal histamine
What causes intravascular thrombosis and ischemic necrosis of gastric mucosa in a dog with a MCT?
Histamine
What causes delayed wound healing in dogs with MCT?
Local effects of proteolytic enzymes and vasoactive amines released by MCT degranulation
What causes local hemorrhage in a dog with MCT following FNA or biopsy?
Heparin released from MCT granules
T/F: A dog diagnosed with MCT should always get survey thoracic rads to look for mets.
False, MCT DO NOT MET TO LUNGS/chest
What do the substages “a” and “b” indicated for MCT staging?
A: no systemic illness
B: Systemic illness
What are the 2 types of histologic classification of MCT in cats? Which is more common? Which variant can sponaneously regress in young cats?
Mastocytic (more common)- compact or diffuse
Histocytic - can regress
What histologic classification for MCTs in dogs is replacing the 3-tier Patnaik system?
Kiupel 2-Tier system
What are the treatment options for canine MCTs if they it is localized but not resectable?
RT alone
Chemo then Sx
Chemo alone
What are the treatment protocols for high risk dogs with MCT? What test should be done on biopsy for these dogs prior to starting therapy with which treatment?
Chemo: Pred/Vinblastine or Cyclophosphamide/Vinblastine
MCT Panel to test for c-kit gene that renders KIT portein active - use to determine if treatment with Palladia is more or less likely to succeed (better if have mutation)
MCT at which locations have the worst prognosis? What location may bode well?
Sublingual, Oral, other Mm’s, Visceral, Bone marrow, Prepuce, Scrotum
Better: SQ
What role does the C-kit mutation have in the prognosis with MCT’s?
If mutation is present, prognosis is worse
T/F: Outcome for a dog with multiple MCT is similar to a single tumor if adequate treatment is initiated for each new mass.
True
Why might BUN be elevated in a dog with a MCT?
Bleeding stomach ulcers
Why does one run a Mast Cell Tumor prognostic panel and what does it evaluate?
How likely the tumor is to respond to different chemo treatments and how aggressive it is
Mitotic count
AgNOR: how fast cell cycle progresses
Ki67: Growth fractions, how fast cells are turning over
KIT: proliferation potential
c-KIT gene mutation: turn over rate
When would you give a dog with a MCT prednisone?
If you want to shrink the tumor so you can do curative surgery later
