Perianal Tumors Flashcards
What is the most common anal sac tumor
Apocrine Gland Anal Sac Adenocarcinoma (AGASACA)
-17% perineal tumors
-2% skin tumors
What are the breed predispositions of Apocrine Gland Anal Sac Adenocarcinoma (AGASACA)
GSD
Spaniels
Dachshunds
Malamutes
At what age do most dogs get Apocrine Gland Anal Sac Adenocarcinoma (AGASACA)
9-11 years old
T/F: Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) has a sex preference for females
False- there are no sex preferences
Are Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) typically unilateral or bilateral
Usually unilateral
10-15% bilateral
(new paper says that 20% neoplastic anal sac detected on histo on contralateral) this is why you might consider bilateral anal sacculectomy but too early now
What are the clinical signs of Apocrine Gland Anal Sac Adenocarcinoma (AGASACA)
Incidental finidng up to 47%- always perform rectal exam and express the anal glands!!
mass effect perineal regions
bleeding/discharge
excessively licking the perineal region
tenesmus/abnormal shape feces
fecal/urinary obstruction
PU/PD (16-53%) secondary to paraneoplastic hypercalcemia
Why should you always express a dog’s anal sacs when doing a physical exam
because you will miss it if it is full
size is very important in prognosis
What is the biological behavior of Apocrine Gland Anal Sac Adenocarcinoma (AGASACA)
aggressive tumor
metastasis at time to presention
LN (25-95%)
Distant (0-40%)
Size of tumor does not correlate with the presence of metastatic disease
20%<2cm masses have metastatic disease
What are the first place that Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) like to metastasis to
Sublumbar lymph nodes
25-95% metastasis at the time of presentation
T/F: the size of Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) tumor correlates with the presence of metastatic disease
False
20% <2cm masses have metastatic disease
How do you work up a case of suspected Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) for staging
FNA anal sac mass
Complete bloodwork- if increased total Ca++ evaluate iCa++ on blood gas
Urinalysis
thoracic imaging (radiographs vs CT)
abdominal imaging (rads vs US vs CT vs MRI) - aspirate abnormal LNs
What does Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) look like on abdominal rads
only extremely enlarged LNs seen
Bone mets
Rads are really useless for staging
What is a good screening test for Apocrine Gland Anal Sac Adenocarcinoma (AGASACA)
Ultrasound
What info about Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) does CT and MRI tell you
able to identify more metastatic LNs and can better visualize the sacral LNs
How do you treat hypercalcemia if significant
1) IV fluid
2) Diuretics
3) Bisphosphonate
4) Calcitonine
For Apocrine Gland Anal Sac Adenocarcinoma (AGASACA), what do you do if LN extirpation
Blood type
How do you do LN extirpation
caudal abdominal approach (umbilicus to pubis)
express bladder before rolling in OR
Know well anatomy-
ureters
internal and external iliac a. and v.
median sacral a. and v.
what is the most common treatment for Apocrine Gland Anal Sac Adenocarcinoma (AGASACA),
Surgery
Anal sacculectomy AND LN extirpation
-Dorsal and sternal recumbency
Both surgeries in dorsal
Always do LN extirpation first
What structures are in the iliosacral lymphocenter
1) Medial iliac LN
-Deep iliac circumflex a. and v.
2) Internal iliac LN
-Internal iliac a. and v.
3) Sacral LN
-Dorsal aspect pelvic canal next to median sacral a. and v.
Where is the medial iliac LN
by the deep iliac circumflex a. and v.
Where is the internal iliac LN
by the internal iliac a. and v.
Where is the sacral LN
by the dorsal aspect pelvic canal next to the median sacral a. and v.
When is surgery for Apocrine Gland Anal Sac Adenocarcinoma (AGASACA) not indicated
1) Invasion to musculature
2) 360 degrees involvement of vessels (both internal and external iliac a. and v.)
3) If extensive seeding to abdominal wall after previous sx (rare)
CT can help you deciding which case is surgical
What position if an anal sacculectomy done in
Sternal recumbency
What instruments are used for Apocrine Gland Anal Sac Adenocarcinoma (AGASACA),
electrocautery
right angle forceps
Gelpi or lone star retractor
What should you do post-op after anal sacculectomy for Apocrine Gland Anal Sac Adenocarcinoma (AGASACA),
usually can go home same day
Liposome encapsulated bupivacaine
NSAIDs
Restage q3-4 months for 18months then q6 months
What should you do post-op after lapartomy and anal sacculectomy for Apocrine Gland Anal Sac Adenocarcinoma (AGASACA),
monitor for possible bleeding overnight
Lipsome encapsulated bupivacaine
Opioids overnight
NSAIDs
After anal sacculectomy, when do you restage
Restage q3-4 months for 18months then q6 months
What are the complications of anal sacculectomy
-Infection (~10%)
-Local recurrence (~20%)
-Transient or permanenet fecal incontinence (rare)
-Rectal perforation (19x risk of post op complications)
-Rectocutaneous fistula
-Hypocalcemia (extremely rare)
What are alternative routes for Apocrine Gland Anal Sac Adenocarcinoma (AGASACA), when surgery (anal succelectomy) is not an option
Radiation responsive tumor
Multiple protocols available (IMRT v SBRT)
Consider surgery for primary tumor and radiation for LNs when not surgical
What chemotherapy options are available for Apocrine Gland Anal Sac Adenocarcinoma (AGASACA)
Different protocols describes (Doxorubicin, carboplatin, cisplatin, mitoxantrone, toceranib)
if no surgery or metastasis to LN
Carboplatin
Gross dz setting - Toceranib
*NO evidence that it does anything
What is the prognosis of Apocrine Gland Anal Sac Adenocarcinoma (AGASACA)
Small <3.2cm AGASACA and no mets- MST = 1237d with no chemo
LN metastasis MST=293-448d
Stage 3b tumors MST surgery 182d vs MST radiation 447d
Distant metastasis MSMT 71-82d
T/F: AGASACA is a radiation response tumor
T
You are presented with a 5yo MC labrador retriever that has a 2 month history of scooting and licking his perineal region. On rectal exam you identify a 1cm mass arising from the left anal sac and no lymphadenopathy. The dog had thoracic radiographs 2 weeks ago at another clinic for coughing and they were remarkable. What are you recommendation to your client as far as next steps?
The mass is most likely an AGASAVA but i cant be sure only based on palpation. I will offer to get a FNA, finish staging the dog with abdominal imaging. Depending on the results I will offer surgery to remove the mass plus or minus the enlarged lymph nodes
The majority of perineal tumors are
perianal gland adenoma
Where does perianal gland adenoma arise from
the circumanal glands
-Prepuce
-Scrotum
-Tail
-Inguinal area
perianal gland adenomas are associated with
plasma androgen levels
-Intact male dogs
-spayed female dogs (evaluate adrenals - rare but testosterone can be secreted)
What breeds commonly get perianal gland adenoma
-Cockerspaniels
-English bulldogs
-Beagles
-Fox terriers
-Dachshunds
-Samoyeds
perianal gland adenoma may ______ but are usually not ___
perianal gland adenoma may ulcerate but usually not invasive or fixed
Are perianal gland adenoma or perianal adenocarcinoma androgen dependent
Perianal adenocarcinomas are NOT androgen dependent
however,
perianal gland adenomas are
What are the characteristics of perianal adenocarcinomas
5-21% of all perianal neoplasms
NOT androgen dependent
locally invasive and can metastasize (15% at presentation)
-Lymph nodes, also lungs, liver, bone, kidney
What breeds typically get perianal adenocarcinomas
GSD and arctic breed
T/F: FNA can differentiate perianal adenomas from carcinomas
False - some data suggest that perianal adenomas may progress to carcinomas
How does perianal adenoma differ from adenocarcinoma
Adenoma: can be single or multiple, can be ulcerated, large or diffuse, not fixed and usually asymptomatic, slower progression
Adenocarcinoma: faster growth rate, fixed to underlying tissues, recur after conservarive therapy, can present with signs like dyschezia or constipation due to LN metastasis
Do perianal adenomas or adenocarcinomas have a faster growth rate
Adenocarcinoma
Do perianal adenomas or adenocarcinomas become fixed to underlying tissues
adenocarcinoma
Do perianal adenomas or adenocarcinomas typically present asymptomatic
Adenoma
Do perianal adenomas or adenocarcinomas present with signs like dyschezia or constipation due to LN metastasis
Adenocarcinoma
Do perianal adenomas or adenocarcinomas have a slower progression
Adenoma
T/F: you should FNA all perineal / perianal masses
True- you may not be able to differentiate adenoma vs adenocarcinoma but can rule out other tumor types
Surgery is main treatment option but surgical dose may vary depending on tumor type
What should you do for AGASACA if LN not resectable or owner is reluctant for surgery
Radiation therapy
T/F: there is no proof of benefit of chemotherapy for regional metastatic AGASACA
True but consider it
For AGASACA, what should you do if recurrence primary/LN metastasis consider *
second surgery (increase survival time, one of the few that increase survival)
