Chapter 33 - Miscellaneous Tumors Flashcards
What tumor suppressor gene is inactivated in >50% of canine HSA?
PTEN
What angiogenic growth factors and receptors have been identified in cHSAs?
Compared to hemangiomas, HSA are strongly positive for what?
VEGF, bFGF, angiopoietins-1 and -2, and their R.
Suggests potential for autocrine stimulation leading to dysregulated proliferation and survival.
PDGFR-B
Increased activity of what signaling pathway has been identified in canine HSA?
NOTCH
Inhibition via y-secretase inhibitors suppresed cell growth
In the dog, what is the most common site for HSA? What are other frequent sites? How about cats?
Spleen
Right atrium, skin, SQ, liver
Cats: cutaneous and visceral are evenly distributed
How does HSA look histologically?
What IHC stains can be requested to dx HSA?
Immature, pleomorphic endothelial cells forming vascular spaces containing variable amounts of blood and thrombi.
An IHC panel is more useful than any marker on its own, as they are not all always expressed and are not specific.
Von Willebrand factor (factor VIII-related antigen
CD31/PECAM)
Other markers that could be used:
- CD117 (KIT)
- Claudin 5
- VEGFA and its receptor Flk-1 - no difference when compared to non-neoplastic endothelial cells
- Ang 2 - may be useful
- Tie 2 - less reliable
How does HSA metastasize? What are the most common places in dogs? Cats?
Hematogenously or through transabdominal implantation following rupture
Dogs: liver, omentum, mesentery, lungs
Cats: liver, omentum, diaphragm, pancreas, lungs
What forms of HSA are an execption to the classic malignant behavior of visceral HSA?
Cutaneous or dermal HSA without any histologic evidence of subdermal infiltration
Approximately what percentage of dogs with splenc HSA will also have right atrial involvement?
25%
What is the most common metastatic brain tumor?
HSA
What morphology of red blood cells has been associated with HSA (2)?
Other blood work abnormalities (3)?
Which is a poor prognostic indicator?
Shistocytes - microangiopathic hemolysis
Acanthocytes - ON THE TEST! (both present in 10%)
Thrombocytopenia - 75-95% - poor PI
Coagulation abnormalities consistent with DIC 50%
Neutrophilic leukocytosis
A 1992 study revealed that thoracic radiographs had a ___% sensitivity and ___% negative predictive value for detecting pulmonary manifestations of HSA.
78% sensitivity
74% NPV
Echocardiogram in dogs with pericardial effusion secondary to right atrial HSA have a visible mass in what % of cases?
65% to 90%
What % of dogs that have a splenectomy for HSA developed arrhythmias? When do these typically resolve? Influence on prognosis?
24%
24 to 48 hours after surgery
Negative prognostic indicator
What chemo durgs have been used in HSA?
Doxorubicin, methotrexate, vincristine, cyclophosphamide, ifosfamide
Doxo + cyclo versus doxo + cyclo + d L-MTP-PE (immunoT)
The MST in the dogs that did not receive L-MTP-PE was ___, compared to ___ for dogs that received it.
Approximately ___% of the dogs in the L-MTP-PE experienced “long term” survival.
6 months vs 9 months
40%
Form of immunotherapy unavailable in USA
Palladia administration to dogs with stage I or II splenic HSA after doxorubicin (q2w) chemotherapy completion.
Overall DFI and MST vs DFI and MST in dogs that received Palladia?
What % of dogs receiving Palladia developed mets?
Overall DFI 140
Palladia DFI 160
Overall MST 170
Palladia MST 170
~5.6m
80%
Did NOT work at all, same numbers as with everything else
MST and DFI for metronomic chemotherapy with etoposide, cyclophosphamide, and an NSAID for K9 HSA as a first line therapy? Thalidomide?
Thalidomide 1-yr SR when used as a first line?
Do they improve MST when administered post doxorubicin completion?
6m - etoposide, cyclo, NSAID
5.6m - thalidomide; stage II MST 10m vs stage III 40d
Thalidomide 1-yr SR 33%
Overall MST for dogs with splenic HSA that receive surgery alone is ___ months.
<1m - 3m
Even with the addition of chemotherapy, < than ___% of dogs with HSA make it to 1 yr.
Surgery plus doxorubicin-based chemo results in a MST to ___ to ___ months.
10%
5 - 6m
What drug when used in a metronomic fashion has been shown to improve TTM and MST?
Thalidomide in addition to doxorubicin and cyclophosphamide
TTM and MST not reached
Overall, what is the MST of cardiac HSA when treated with surgery alone, chemo alone, and sx + chemo?
Sx alone: MST 1-4m
Chemo alone: MST 3.8m
Sx + chemo: MST 5.4m
In cats with visceral HSA, what is the prognosis?
What is the local recurrence rate of feline cutaneous and subcutaneous HSA following sx?
Poor60 to 80%
From what cell do thymomas originate?
What are the different histologic types and which one is the most common in dogs?
Thymic epithelial cells
Histologic types:
- Differentiated epithelial -> most common one
- Lymphocyte rich
- Clear cell type
Infiltration of thymomas by which cell is positively correlated with improved survival in both dogs and cats?
Lymphocytes
What is the most common form of thymomas in cats and how does int influence prognosis?
Cystic
How are thymomas classified as benign or malignant?
Degree of invasiveness
Ability to surgically excise them
(Rather than histologic features)
What is the metastatic rate of thymomas in dogs and cats?
Dogs - rare
Cats with cystic thymoma - 20%
What are the 3 most common differentials for mediastinal masses?
Lymphoma, thymoma, ectopic thyroid tumor
Other: branchial cysts, rare sarcomas, metastatic neoplasms
Explain the maturation process of T lymphocytes
Thymic cortex -> maturation of T lymphocytes
Thymic medulla -> composed of epithelial cells/thymocytes
TCL precursors express CD34. When TCL precursors enter the thymic cortex, they loose expression of CD34, and express CD5 and CD3. They then evolve from double negative cells, to double positive CD4+ and CD8+ cells. When they leave the thymus, they loose co-expression and are committed to either a CD4+ or CD8+ lineage.
Paraneoplastic syndromes are reported to occur in ___% of dogs with thymoma.
What are some reported PNS?
When can these tend to occur?
67%
PNS:
- Myasthenia gravis
- Exfoliative dermatitis
- Erythema multiforme
- Hypercalcemia
- T-cell lymphocytosis
- Anemia
- Polymyositis
At presentation, later in the course of the disease, after tumor removal
Myasthenia gravis occurs in up to ___% of dogs with thymomas and has also been reported in cats.
Concurrent megaesophagus and aspiration pneumonia is present in ___% of dogs with MG.
What % of cats with MG have mediastinal masses?
40% (both first answers)
50% of cats with MG have mediastinal masses
What 3 CBC abnormalities may be seen in dogs with thymoma?
Anemia, thrombocytopenia, and lymphocytosis
Hypercalcemia as a PNS in dogs with thymoma can occur in up to ___% of cases and is secondary to production of what?
34%
PTH-rp
What confirmatory test should be done if MG is suspected?
Demonstration of serum antibodies against ACH receptors (MG Ab titers)
Tensilon test with edrophonium, an ultra short acetylcholinesterase inhibitor agent (anticholinesterase)
How do cytologic samples from thymoma tumors look like?
What % of samples contain epithelial cells?
Neoplastic to normal epithelial cells, large numbers of mature small lymphocytes, ocasional mast cells. Usually normal appearing epithelial cells vs thymic carcinoma.
60%
Non-diagnostic samples are common due to presence of only lymphocytes and no epithelial cells
How can a thymoma be differentiated from lymphoma or thymic carcinoma?
Flow cytometry. IHC not helpful
More than 80% of thymic lymphocytes should co-express CD4 and CD8.
Thymoma >10% of lymphocytes co-express CD4 and CD8
LSA <2% of lymphocytes co-express CD4 and CD8
Carcinoma <1% of lymphocytes co-express CD4 and CD8 and samples usually have a low lymphocyte count (<40%)
What is the standard of care treatment for thymomas?
No standard of care or studies comparing different treatments
What is the MST in dogs and cats with thymoma that undergo surgical resection?
Perioperative mortality in both spp?
Dogs: MST 1.7-2 years
Cats: MST 4-5 years
Perioperative mortality 20%
ORR of RT in dogs and cats with thymoma?
ORR 50-75%,
Dogs MST 8
Cats MST 2 yrs
Some px treated with RT alone, other with sx, RT, and chemo.
What % of dogs and cats eventually die from their thymoma?
Dogs - 40%
Cats - 20%
Positive (1) and negative (6) prognostic factors identified in px with thymoma?
PPI - degree of lymphocyte infiltrate = improved ST in both dogs and cats
NPI dogs for a shorter ST: Presence of another tumor at dx Lack of surgical excision Incomplete histologic excision Masaoka stage III+ PNS: hypercalcemia, MG Tx with adjuvant chemo or RT
PNS did NOT affect ST in another study
What is a TVT and how does it spread?
Horizontally transmitted infectious histiocytic tumor usually spread through damaged mucosal epithelium from coitus, licking, biting, and sniffing
What are the most common sites of involvement for TVT?
Genital mucosa, nasal and oral cavities, SQ tissues, eyes
External genitalia - caudal aspect of the penis in males, posterior vagina or vestibule in females
Also nasal and oral cavities
Spontaneous regression with TVT’s is seen secondary to what? When does it occur? At what point in time is it not likely to not regress on its own?
Immune responses against the tumor
3-6 months
9 months
TVT’s are seen in dogs of what age usually?
2 to 5 yrs
Metastasis in TVT can be seen in ___ to ___% of cases. What are the most common places?
5 to 17%
Draining lymph nodes (inguinal, tonsillar, iliac), SQ, skin, eyes, oral mucosa, liver, spleen, BM
Some of these may represent autotransplantation
How is TVT cytologically described?
For what IHC does it stain positive (4)?
Round cell tumor with many discrete clear cytoplasmic vacuoles
Vimentin, lysozyme, alpha-1-antitrypsin (AAT), macrophage specific ACM1, GFAP
What intracellular bacteria has been associated with TVT cells?
Leishmania
Can be co-transmitted along with the tumor
In addition to cell-mediated immunity, what other immune response does TVT also elicits?
Humoral immune response demonstrable by antibodies against TVT antigens
During which phase are high numbers of lymphocytes and mast cells are seen to be infiltrating TVT’s?
R (regression) phase - lymphocytes
P (progressive) phase - mast cells
A complete response is seen in ___ to___% of dogs with TVT when treated with single agent ____ once weekly for 3 to 6 treatments.
Resistant cases can be treated with which chemotherapy drug or what other treatment modality?
Vincristine ORR 90 to 95%
Doxorubicin, RT
Surgery for TVT’s has an overall local recurrence of ___ to ___%.
30 to 75%
What % of dogs with a splenic mass and hemoabdomen have HSA (range)?
60-70%
What % of NON-ruptured splenic masses are benign vs malignant?
Presence of what finding on US was suggestive of malignancy?
Benign - 70%
Malignant - 30%
Hypoechoic nodules
Out of dogs with concurrent splenic and hepatic masses, what % had benign vs malignant dz? What % of malignant masses were HSA?
Benign 27%
Malignant 48%
77%
Dogs with splenic masses that weigh more than ___kg are more likely to have HSA.
> 27.8kg
When comparing the site and cause of spontaneous hemoabdomen, dogs weighing < ___kg were more likely to be bleeding from which organ vs dogs weighing > than ___kg.
< 20kg liver
> 20kg spleen
Although there is no difference in cytology of pericardial effusion in dogs with HSA vs other tumors, dogs with HSA have elevated levels of what when compared to dogs with idiopathic effusions?
Troponin I
If > 0.25 ng/mL more likely to be cardiac HSA
What % of dogs with splenic HSA and grossly abnormal looking livers have HSA metastasis?
50%
What is the sensitivity and specificity of gross dark lesions on the liver in dogs with splenic HSA?
85% for both
What % of dogs undergoing laparoscopy for splenic HSA have to convert to open laparotomy?
What influenced this?
27%
Heavier body weight was significantly associated with conversion; OR 1.6
Splenic mass, BCS, were not
Doxorubicin q2 weeks MST for stage I, II, and III canine visceral HSA?
I - 8.5m
II - 7m
III - 3.5m
Doxorubicin ORR for gross cardiac and non-cardiac HSA?
Cardiac - ORR 40%, biologic response 70%
Non cardiac - ORR 40 to 50%
VAC for canine HSA ORR, CR, PR and overall MST?
Any difference in ST depending on stage?
ORR 90%, CR 43%, PR %43
Overall MST 6m, if CR 9m (lived longer than PR)
No
Doxo and concurrent cyclophosphamide administration can result in what in dogs with HSA?
Shorter ST
Alternated CCNU and doxo for K9 HSA MST? 1-yr SR?
5m
16% 1-yr survival rate
Ifosfamide MST for K9 HSA?
5m