Soft Tissue Sarcomas Flashcards
Withrow 2019 - Chapter 22
1
Q
What tissues do STS arise from?
A
Mesenchymal
2
Q
What have sarcomas been associated with in dogs?
A
Radiation, trauma, foreign bodies, orthopedic implants, and the parasite Spirocerca lupi
3
Q
Age, breed, sex, and size predilection for STS (dogs)
A
Middle-aged to older
No breed
No sex
Large-breed dogs
4
Q
Biologic behavior of cutaneous and subcutaneous STS
A
Locally expansive mass growing between fascial planes, but also can be infiltrative. Often surrounded by a pseudocapsule.
5
Q
Cutaneous and subcutaneous STS recurrence rate and metastatic rate
A
Low to moderate recurrence rate after surgical excision with or without adjuvant RT
Low metastatic rate
6
Q
Likelihood of local recurrence of STS depends on what?
A
Tumor size, degree of infiltration, completeness of histologic excision, histologic grade
7
Q
Likelihood of metastasis of STS depends on what?
A
Primarily on histologic grade
8
Q
Describe the STS grading system
- Differentiation
- Mitosis
- Necrosis
A
Grade 1
- Differentiation: resembles normal adult mesenchymal tissue
- Mitosis: 0-9
- Necrosis: None
Grade 2
- Differentiation: Specific histologic subtype
- Mitosis: 10-19
- Necrosis: <50%
Grade 3
- Differentiation: undifferentiated
- Mitosis: >20
- Necrosis: >50%
9
Q
Name STS tumors of fibrous tissues (4)
A
Nodular fasciitis (fibromatosis, pseudosarcomatous, fibromatosis), fibrosarcoma, pleomorphic sarcoma (malignant fibrous histiocytoma), myxosarcoma
10
Q
Benign non-neoplastic lesion arising from the subcutaneous fascia or superficial portions of the deep fascia in dogs
A
Nodular fasciitis (fibromatosis, pseudosarcomatous, fibromatosis)
11
Q
Appearance of nodular fasciitis
- Grossly
- Histologically
A
Grossly - nodular, poorly circumscribed, and very invasive
Histologically - large plump or spindle-shaped fibroblasts in a stromal network of variable amounts of collagen and reticular fibers with scattered lymphocytes, plasma cells, and macrophages
12
Q
Variant of nodular fasciitis characterized by fibroblast proliferation with a dense reticular fiber network and mucoid material
A
Infantile desmoid-type fibromatosis
13
Q
Nodular fasciitis
- Treatment
- Recurrence
- Metastasis
A
- Treatment: wide excision usually curative
- Recurrence: local recurrence possible with incomplete resection
- Metastasis: do not metastasis
14
Q
Tumor arising from malignant fibroblasts
A
Fibrosarcoma (FSA)
15
Q
Age, breed, sex, and size predilection for FSA
A
Older dogs and cats (Dogs with FSAs were significantly younger than dogs with other histologic subtypes of STS in one study)
No breed or sex predilection (higher predilection for Goldens and Dobermans in one study)
16
Q
Fibrosarcoma
- Recurrence
- Grade
A
- More likely to recur after incomplete histologic excision
- Have higher mitotic rates than other histologic subtypes but are more likely to be low grade
17
Q
Age, breed, sex, and site predilection for pleomorphic sarcoma (malignant fibrous histiocytoma)
A
Middle-aged to older dogs
Flat-coated retrievers, Rottweilers, Goldens
No sex predilection
SQ tissues of the trunk and pelvic limbs and spleen
18
Q
Histologic subtypes of pleomorphic sarcoma (4)
A
Storiform-pleomorphic
Myxoid
Giant cell
Inflammatory
19
Q
IHC staining for pleomorphic sarcoma
A
Definitive IHC staining patterns have not been established; typically vimentin positive and CD18 negative
20
Q
Pleomorphic sarcoma
- Grade
- Metastasis
A
- More likely to be high grade
- More likely to have metastasis at time of diagnosis compared with other subtypes
21
Q
Neoplasms of fibroblast origin with an abundant myxoid matrix composed of mucopolysaccharides
A
Myxosarcoma
22
Q
Age and site predilection for myxosarcoma
A
Rare tumor
- Middle-aged to older dogs and cats
- SQ tumors of the trunk and limbs, heart, eye, and brain
- Tend to be infiltrative growths with ill-defined margins
23
Q
Tumors derived of the different cellular components of vascular wall, excluding the endothelial lining
A
Perivascular wall tumor (PWT)
24
Q
PWT
- Biologic behavior
- Recurrence
A
- Less aggressive biologic behavior
- Significantly lower rates of local recurrence than other histologic subtypes
25
Tumors of nerve sheath origin, arising from Schwann cells, perineural cells, or perineural or endoneural fibroblasts.
Peripheral nerve sheath tumors
26
Most common benign PNST (2)
Schwannomas and neurofibromas
27
How can malignant PNST be differentiated from PWTs based on IHC staining?
Malignant PNSTs stain positive with S-100, vimentin, glial fibrillary acidic protein (GFAP), nerve growth factor receptor, and neuron-specific enolase.
PNSTs have significantly higher Ki67 index than PWTs.
28
PNST
- Location and biologic behavior
- Recurrence
- Metastasis
- Often subcutaneous,
poorly circumscribed, adherent to deeper tissues and may infiltrate underlying fascia, muscle, and skin. Tend to be slow growing (often confused with lipomas on PE)
- Local recurrence common after conservative surgery
- Modest metastatic rate
29
Types of PNST of macroscopic nerves (3)
Peripheral
Root
Plexus
30
Clinical signs of plexus PNST
unilateral lameness, muscle atrophy, paralysis, and pain.
31
Treatment for PNST
surgery, surgery with adjuvant RT, or RT alone
32
Life-limiting factor for PNST
Regardless of histologic grade, local disease usually limits survival before metastasis occurs.
33
Benign tumors of adipose tissue
Lipoma
34
Three morphologic types of lipomas
Regular
Intermuscular lipomas
Infiltrative lipomas
35
Lipoma
- Age
- Clinical signs
- Location
- Treatment
- Recurrence
- Older dogs
- Rarely symptomatic, if so are secondary to compression or strangulation
- Mostly subcutaneous but have been reported in thoracic cavity, abdominal cavity, spinal canal, and vulva/vagina of dogs
- marginal excision recommended for those that interfere with normal function but majority do not need surgery
- Surgery usually curative but local recurrence has been noted
36
Most common location of intermuscular lipomas
Caudal thigh of dogs, particularly between the semitendinosus and semimembranosus muscles; also reported in axilla
37
Uncommon tumors composed of well-differentiated adipose cells without evidence of anaplasia
Infiltrative lipoma
38
Biologic behavior of infiltrative lipomas
Considered benign and do not metastasize but are locally aggressive and commonly invade adjacent muscle, fascia, nerve, myocardium, joint capsule, and bone
39
Treatment options for infiltrative lipomas
Aggressive treatment, including amputation, may be necessary for local control. RT can be considered either alone or in combination with surgical excision.
40
What is the prevalence of FISS?
## Footnote
AH
1-4/10K cases
but can be as high as 13-16/10K cases!
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
41
How did the ratio of FISS to non-ISS changed between 1984 and 1994?
## Footnote
AH
Increased from 0.5 to 4.3
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
42
How long after vaccination, FISS can occur?
## Footnote
AH
4 weeks - 10 years
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
43
Are non-adjuvanted vaccines associated with a lower risk of causing FISS compared to adjuvanted vaccines
## Footnote
AH
Unclear!
This theory has been proposed but 3 large epidemiologic studies did not provide evidence that aluminum-containing vaccines pose a greater risk of FISS.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
44
What are the local recurrence rates with surgery + radiation therapy for STS?
Overall: 20 - 40%
1 year: 70 - 85%
2 year: 60 - 80%
3 year: 57 - 80%
4 year: up to 80%
45
What is the median time to recurrence?
14 - 27 mos (412 - >798d)
Grade 1 & 2: >47 mos (>1416d)
Grade 3: 2.5 mos (78d)
46
MST for incomplete surgical excision + fRT?
Overall: 76 mos (2270d)
1 year: 80-87%
2 year: 72-87%
3 year: 92%
5 year: 76%
47
At what mitotic count is a soft tissue sarcoma treated with sx + RT more likely to recur with a shorter OST?
MC >9/10 hpf
48
What is the rate of local recurrence following sx + hypofractionated RT?
~20%
49
What is the progression free interval following sx + hRT?
greater than or equal to 23 mos (698d)
50
What percentage of patients are free of local recurrence following sx + hRT at 1 year? 2 & 3 years?
1 - 80%
2 & 3 - 73%
51
What should the timing of hRT post-operatively be to improve outcome?
>4 weeks
52
What is the progression free survival following hRT by grade?
Grade 1: 63.5 mos (1904d)
Grade 2: 19 mos (582d)
Grade 3: 10 mos (292d)
53
What is the OST following hRT by grade?
Grade 1 & 2: not reached
Grade 3: 31 mos (940d)
54
What is the metastatic rate of STS by grade?
Grade 1: 0 - 15%
Grade 2: 5 - 25%
Grade 3: 20 - 45%
55
How to differentiate FISS from non-ISS by IHC?
## Footnote
AH
ISS: positive for PDGFR, EGFR, TGF-β
Non-ISS: negative or faintly positive for these.
Lymphocytes, regional macrophages and ISS neoplastic cells are all positive for PDGFR.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
56
Which gene is expressed more in FISS vs non-ISS?
## Footnote
AH
tive in ISSs and not expressed in non–injection-site FSAs.205,206
FeLV and the feline sarcoma virus are not involved in the patho-
genesis of feline ISSs.207
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
57
There are many similarities between histologic subtypes and
biologic behavior of STSs in cats and dogs.
What are the 3 main exceptions in cats?
## Footnote
AH
1. FISS
2. Virally induced multicentric FSA
3. The relative rarity of PNST, SCS, and HS
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
58
How FISS and non-ISS are different clinically?
## Footnote
AH
FISSs are usually large with a rapid growth rate and typically arise from the subcutis at sites consistent with the administration of vaccines and other injections, such as the interscapular region, body wall, and pelvic limbs, whereas non-ISSs are smaller, slower growing, and will often arise from the skin rather thansubcutaneous tissue
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
59
How to differentiate FISS from non-ISS histologically (other than IHC)?
## Footnote
AH
ISSs have histologic features consistent with a more aggressive biologic behavior than non–ISSs, such as:
marked nuclear and cellular pleomorphism
increased tumor necrosis,
high mitotic activity,
multinucleate giant cells
+
the presence of a peripheral inflammatory cell infiltrate consisting of lymphocytes and macrophages
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
60
In a series of 91 cats with histologically confirmed and graded ISSs, the prevalence of high-grade lesions was substantially higher than reported in dogs,
What percentage of cats in that series were diagnosed with grade III and grade I tumors?
## Footnote
AH
~60% grade III
~5% grade I
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
61
Microscopically, areas of transition between inflammation and tumor development are frequently observed in cats with FISS.
What common observation is made about the macrophages present in these areas?
## Footnote
AH
The macrophages contain a bluish gray foreign material (consistent with aluminium hydroxide, the common vaccine adjuvant)
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
62
FISSs are histologically similar to what other type of feline tumor?
## Footnote
AH
Sarcomas arising from traumatized eyes
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
63
CT and MRI are both very sensitive for the detection of the peritumoral extent of cats with suspected FISSs.
What percentage of these peritumoral lesions are neoplastic?
## Footnote
AH
~40%
Up to 60% of these peritumoral lesions are non-neoplastic when examined histologically.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
64
Why excisional biopsy of suspected FISSs are not recommended?
## Footnote
AH
Increased risk of local recurrence
Significant decrease in DFI and ST.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
65
What is the MST for dogs with STS with Sx alone or Sx + adjuvant RT?
## Footnote
AH
The majority of studies can't report MST because only 10-30% of dogs die after curative-intent treatment for STS.
Sx alone: 1013 -1796d (~ (2y9mo-5y1mo)
Sx + RT: 2270d (6y3mo)
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
66
What are the 1-, 2-, 3-, 4-, and 5-yr survival probablities for dogs with STS treated with curative intent?
## Footnote
AH
1-yr: 80% to 94%
2-yr: 72% to 87%
3-yr: 61% to 81%
4-yr: 81%
5-yr: 76%
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
66
What is the impact of **tumor invasiveness** on tumor-related deaths in dogs with STS?
## Footnote
AH
Dogs with grossly invasive and fixed STSs have a 5-fold increased risk of tumor related deaths, presumably because of greater difficulty in achieving complete excision of their STSs.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
67
What is the impact of **surgical approach** (curative vs non-curative intent) on MST of dogs with STS?
## Footnote
AH
Curative-intent: 1306 d (~3y7mo)
vs.
Non-curative intent: 264d (~9mo)
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
68
What is the impact of **completeness of excision** on MST in dogs with STS?
## Footnote
AH
Complete excision: 1306d (~3y7mo)
vs.
Incomplete excision: 657d (~1y10mo)
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
69
What is the impact of **local tumor recurrence **on tumor-related deaths in dogs with STS?
## Footnote
AH
5X risk of tumor-related death in dogs with recurrence vs. without.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
70
What is the impact of **tumor necrosis** on tumor-realted deaths in dogs with STS?
## Footnote
AH
3X more likely when >10% necrosis was present.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
71
What is the impact of **>20 MF**/10 HPF on tumor-realted deaths in dogs with STS?
## Footnote
AH
3X more
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
72
What is the MST for dogs with STS, based on **MF**/10 HPF?
<10, 10-19, >20
## Footnote
AH
<10: 1444d (~3y11mo)
10-19: 532d (~1y5mo)
>20: 236d (~7mo)
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
73
Impact of histologic grade on MST in dogs with STS, treated with RT?
## Footnote
AH
grade I: MST not reached
grade II: >1461d (4 years)
grade III: 78d (3 mos)
Incompletely excised STS + fractionated RT, grade III:
135d
vs.
Incompletely excised STS + hypofractionated RT, grade I and II:
MST not reached.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
74
Impact of **AgNOR** (below and above the median AgNOR scores) on MST and survival ratesfor dogs with STS?
Chances of dying from tumor with increased AgNOR score?
## Footnote
AH
AgNOR1188d (3y1mo), 76%
vs
AgNOR>median: >1306d (~3y7mo), 53%
77X more likely
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
75
Impact of Ki67 on MST and survival rates in dogs with STS?
## Footnote
AH
Ki67>median: 657d (22 mos)
Ki671188d (40 mos) , 94% survival
Increased Ki67: 12X more likely to die as a result of their dz
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
76
Overall metastatic rate and median time to metastasis in dogs with STS?
## Footnote
AH
0-31%
median time to metastasis of 230 to 365 days (~8mo-1yr)
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
77
What are the factors that increase the risk of metastasis in dogs with STS, and what is the impact of each one?
## Footnote
AH
1. Histologic grade:
grade I: 0-13%
grade II: 7-27%
grade III: 22-44%
2. >20 MF/10HPF: X5 more likely
3. More likely in pleomorphic and undifferentiated sarcomas compared with FSAs, PNSTs, myxosarcomas, and liposarcomas
4. In one study, no dog with a STS at or below the level of the elbow or stifle
developed metastatic disease
5. Percentage of necrosis
6. Local tumor recurrence
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
78
What is the overall local recurrence rates in dogs with STS?
After wide resection
After marginal resection
After incomplete histologic excision + fractionated RT
After incomplete histologic excision + hypofractionated RT
## Footnote
AH
After wide resection: 0-5%
After marginal resection: 11-29%
After incomplete histologic excision + fractionated RT: 17-37%
After incomplete histologic excision + hypofractionated RT: 18-21%
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
79
What chemotherapy protocols improve local tumor control for canine STS?
Metronomic cyclophosphamide
Intralesional chemotherapy
80
What is the likelihood of local recurrence after surgery + intralesional chemotherapy?
15 - 30%
81
What is the complication rate after treatment with Sx + intralesional chemotherapy?
Wound complications - 50 - 85%
82
What is the likelihood of complete histopathologic excision for FISS with 2-3 cm lateral margins? 4-5 cm lateral margins?
2-3 cm: <50%
4-5 cm: 95-97%
83
What is the percentage of local recurrence based on histopathologic margins for FISS?
Complete: 15 - 20%
Incomplete: 60 - 70%
84
What is the 1 and 2 year disease free rate for FISS with 2-3 cm margins?
1 year: 35%
2 year: 9%
85
What is the 3 year disease free rate for FISS with 5 cm margins?
85%
86
What is the overall likelihood of recurrence with Sx + RT for FISS? With complete histologic margins? Incomplete?
Overall: 30 - 45%
Complete: 40%
Incomplete: 30%
87
What is the DFI for FISS with Sx + RT?
13 - 37 mos
Complete: 23 - 33 mos (700 - 986d)
Incomplete: 4 - 10 mos (112 - 292d)
88
What is the time to first recurrence for FISS treated with Sx + RT with complete histologic margins? Incomplete?
Complete: 11 - 14 mos (325 - 419d)
Incomplete: ~3 mos (79d)
89
DFI and dz-free rates for dogs with STS, treated with Sx alone vs incomplete excision + fractionated RT vs. incomplete excision + hypofractionated RT.
## Footnote
AH
The DFIs and local tumor control rates are also similar between the different treatment options,
Sx. alone:
DFI: 368-637d to not reached.
1-yr dz-free: 89-93%
2-yr dz-free: 78-82%
e-yr dz-free: 66-76%
Incomplete excision + fractionated RT:
DFI: 412 or >798d
1-yr dz-free: 71-84%
2-yr dz-free: 60-81%
3-yr dz-free: 57-81%
4-yr dz-free: up to 81%
Incomplete excision + hypofractionated RT:
DFI 698d to not reached
1-yr dz-free: 81%
2-yr dz-free: 73%
3-yr dz-free: 73%
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
90
What are prognostic factors for recurrence of FISS?
tumor size, Sx dose/aggressiveness, complete histologic margins, grade
91
What are the metastatic rates for FISS based on grade?
Grade 1: 0 - 17%
Grade 2: ~20%
Grade 3: 20 - 100%
Overall: 0 - 25%
92
What is the MST for FISS with Sx 4-5 cm lateral, 2 fascial planes deep?
27 - 30 mos (804 - 901d)
93
What is the MST for FISS with less aggressive Sx?
13 - 20 mos (>395 - 608d)
94
What is the MST for Sx + RT for FISS? Survival rates for 1, 2, and 3 years?
Overall: 17 - 43.5 mos (520 - 1307d)
1 year: 60 - 85%
2 year: 40 - 70%
3 year: 30 - 70%
95
What are the prognostic factors for MST for FISS?
anemia, tumor size, treatment type, histologic subtype, mitotic rate, local tumor recurrence, metastasis
96
What is the PCV cutoff for impact on MST for FISS?
25%
MST PCV <25%: 10 mos (308d)
MST PCV >25%: 25 mos (760d)
PCV <25% SR: 1 year - 40%, 2 year - 24%
PCV >25% SR: 1 year - 72%, 2 year - 50%
97
What are poor prognostic factors for local tumor control in dogs with STS?
## Footnote
AH
Large tumor (>5cm)
Infiltrative tumors
Tumors in locations other than limbs at or below the elbow or stifle
Histologic subtypes
Grade III STS
Incomplete surgical margins
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
98
How does tumor size impact prognosis with surgery alone for FISS?
MST
<2 cm: 21 mos (643d)
2-5 cm: 19 mos (558d)
>5 cm: 13 mos (394d)
99
What is the impact of preoperative RT on MST for FISS? Postoperative RT?
Preop: 10 mos (310d)
Postop: 23.5 mos (705d)
100
What is the 1 and 2 year survival rate with preoperative RT for FISS? Postop?
Preop: 1 year - 40%, 2 year - 30%
Postop: 1 year - 70%, 2 year - 50%
101
Which histologic subtype of FISS has the worst prognosis?
MFH (malignant fibrous histiocytoma) - MST 10 mos (290d) vs ~21 mos for FSA and PNST
102
What is the MST for FISS with a mitotic rate >20?
33 mos (994d)
103
What is the MST for FISS that had recurrence? Without recurrence?
(+) 11 - 17 mos (327 - 499d)
(-) 37 - 49 mos (1098 - 1461d)
2 year survival rate: (+) 40%, (-) 75%
104
What is the MST for FISS with and without metastasis?
With: 5.5 - 13 mos (165 - 388d)
Without: 31 - 51 mos (929 - 1528d)
105
What is the 3-2-1 rule for FISS?
Investigate if:
3 - Mass present >/= 3 mos after vax
2 - Mass is > 2cm diameter
1 - Increase in size > 1 mo after vax
106
Where are the appropriate sites for vaccination for cats for each vaccine?
Rabies: distal RPL
FeLV: distal LPL
All other: R shoulder
107
Local recurrence grade III STS vs low-grade?
## Footnote
AH
6X greater risk of local recurrence
In one study of 236 dogs with subcutaneous STSs
treated with excisional biopsy, the local recurrence rate was 0% for
STSs excised with complete histologic margins and 19% overall
for incompletely excised STSs.
The recurrence rate for incom-
pletely excised grade I, II, and III STSs was 7%, 34%, and 75%
(three of four) respectively.
## Footnote
Withrow 2019 - Ch 22 - Soft Tissue Sarcomas
108
Minimum recommended surgical margins of STS
2-3cm lateral and one fascial layer deep to the tumor
109
Dogs with complete incision are ____ times less likely to have local tumor recurrence compared with dogs with incompletely excised STS
10.5x
110
Local recurrence rate for an incompletely excised grade I STS
7%
111
Local recurrence rate for an incompletely excised grade II STS
34%
112
Bleomycin electrochemotherapy for incompletely excised STS - what is the overall local recurrence rate? Mean time to recurrence?
36%, 730 days
113
True to false, ISSs are well encapsulated tumors
false (poorly encapsulated and infiltrative along fascial planes)
114
Recommended surgical margins for ISS
5cm lateral and two fascial layers deep
115
Median time to first recurrence after marginal resection of ISS compared to wide to radical
79 days vs. 325 to 419 days
116
When using 2 to 3 cm surgical margins for ISS in cats, complete resection is achieved in what percent of cats? What are the 1 and 2 year disease free rates?
<50% of cats, 35% and 9%
117
What cells do liposarcomas arise from?
lipoblasts, lipocytes
118
What are metastatic sites of liposarcoma?
lungs, liver, spleen, bone
119
What is the metastatic rate of liposarcomas (high/moderate/low)?
low
120
Where are liposarcomas commonly found?
SQ, especially along the ventrum and extremities
121
What cytological stain can help to differentiate between liposarcomas and other STS?
Oil Red O
122
How can CT differentiate liposarcomas from regular and infiltrative lipomas?
liposarcomas appear as mixed-attenuating, heterogenous, multinodular, and contrast enhancing masses
123
What is the prognosis for liposarcoma w/surgical excision?
good, MST after wide excision is 1,188 days
124
What is MST for liposarcoma that is marginally excised? Incisional biopsy?
1. 649 days
2. 183 days
125
What cell type do rhabdomyosarcomas originate from?
myoblasts or primitive mesenchymal cells
126
What sites are rhabdomyosarcomas most likely to arise from in dogs?
urinary bladder, retrobulbar musculature, larynx, tongue, myocardium
127
What is the metastatic potential of rhabdomyosarcoma?
low to moderate,
metastatic sites include lungs, liver, spleen, kidneys, adrenal glands.
128
What are the histological classifications of rhabdomyosarcoma?
embryonic, botryoid, alveolar, pleomorphic
129
What IHC staining may be necessary to diagnose rhabdomyosarcoma?
vientin, skeletal muscle actin, myoglobin, myogenin, myogenic differentiation (MyoD)
130
What is the metastatic rate for boytroid rhabdomyosarcoma?
27%
131
What is the metastatic rate for embryonal and alveolar rhabdomyosarcoma?
50%
132
Metastatic disease in dogs with rhabdomyosarcoma is more common in what age group?
<4 years
133
What cell does lymphangiosarcoma arise from?
lymphatic endothelial cells
134
Describe the appearance of lymphangiosarcoma?
soft, cystic like, edematous mass, usually in the subcutis. Most often associated with extensive edema or nonhealing, discharging wounds
135
What IHC markers can be used to differentiate between lymphangiosarcoma and hemangiosarcoma?
CD31, factor VIII-related antigen, lymphatic vessel endothelial receptor 1 (LYVE-1), propsero-related homeo box gene-1 (PROX 1)
136
What is the MST for dogs with lymphangiosarcoma with no treatment vs surgery vs surgery/RT/chemo?
No treatment: 168 days
Sx alone: 487 days
Sx/RT/chemotherapy: 574 days
137
What is a malignant mesenchymoma?
STS comprising a fibrous component with two or more different vvarieties of other types of sarcomam
138
What is the growth rate of malignant mesenchymoma?
slow
139
What is the MST for dogs with splenic mesenchymoma?
12 months
140
What is the cytologic accuracy of correctly diagnosing STS?
63-97%
141
What percentage of preoperative biopsies are successful at determining histologic grade of STS?
59%
underestimated grade in 29%
overestimated in 12%
142
1 and 2 year tumor control for RT alone (50gy)
50%, 33%
143
Median PFI for hypofractionated RT in macroscopic STS
155-419 days
144
Prognostic factors for median PFI for hypofractionated RT
Tumor location - significantly better for limbs (466 days) than head or trunk (110 days)
Previous surgeries - dogs treated with more than one surgery had a significantly decreased median PFI (105 days) compared with dogs treated with one or no surgery (420 days)
145
MST after hypofractionated RT for macroscopic
STS
206 to 513 days
146
What factor has a significant effect on MST for hypofractionated RT for macroscopic STS?
location - STSs located on the limbs (579 days)
having a better outcome than those on the head (195 days) or trunk (190 days).
**40% of dogs in this study were also treated with metronomic chemotherapy**
147
Rationale for preoperative RT for STS
(1) the radiation field is smaller because, after surgery, the entire surgical site must be included in the field plus a margin of normal tissue and this may contribute to local toxicity
(2) a large number of peripheral tumor cells are inactivated (with reduced contamination of the surgical site)
(3) tumor volume reduction may make surgical resection less difficult
