82.Skin dz Flashcards
% of histologically malignant skin tumors in dogs vs cats
20-40% M in dogs50-60% M in cats
what is the most important factor in local tumor control
surgical wound margin!1. intracapsular/intralesional (debulking or cytoreductive; leave macroscopic disease)2. marginal (often within pseudo capsule leaving microscopic disease behind)3. wide (removing some normal tissue)4. radical (an entire compartment is removed
4 surgical principles for tumor resection
- early ligation of large tumor vessels to minimize tumor cells entering circulation2. stay sutures, allis tissue forceps to avoid touching tumor3. change instruments/gloves if manipulating tumor4. copious lavage5. remove benign tumors first!
tissues most sensitive to chemotherapy and wound healing
intestinal tissues are most sensitivein general start chemo 7-10 days post surgeryneed more research
effects of radiation therapy on wound healing
dose-dependent injury to tissuestissue damage is more permanent than that of chemousually advised to start radiation therapy 1-3 weeks post op
4 types of radiation therapy injury to local tissues
- local erythema2. dry desquamation (superficial)3. moist desquamation (loss of basal layer of epidermis) 4. necrosis (dermal destruction/irreversible ulcer)
TNM staging system
T tumor size and invasiveness 0, 5 cm, invasionN node involvement 0, 1–ipsi, 2–contra or bilateral, 3–fixedM presence of distant mets 0–no, 1–yes
accuracy of FNA for diagnosing neoplasia
90%can be diagnosed cytologically but still need bx for tumor grade and confirmation of tumor origin
difference in spread of epithelial vs mesenchymal tumors
epithelial–lymphaticsmesenchymal–hematogenous
CT vs radiographs for detection of pulmonary nodules or mets
CT 1 mmradiographs 7-9 mm
2 main functions of the lymphatic system
- transport (lymph,lipids, fluid excess, cell debris/nutrients)2. immune response
eventually lymph enters systemic circulation via
thoracic duct
cortex and medulla of a lymph node
cortex: contains B cells arranged in follicles with germinal centers (Bcells and plasma cells) that is surrounded by rim of T cellsparacortex: t cells and APC (macros)medulla: cords of lymphocytes, macros, plasma cells; btwn cords are sinuses with discontinuous endothelium
how to determine a sentinel LN
blue dye or low dose radio nucleotide and gamma cameramany nodes may be draining tumor area so hard to know which to remove for staging purposes which may or may not be prognostic for the type of tumor in question (controversial)
potential benefits of lymphadenectomy
- possibly slow the rate of mets2. may reduce clinical signs of paraneoplastic syndrome or palliate symptoms3. tumor debulking to increase local control 4. staging of diseaseonly helpful if removing the lymph node draining tumor and multiple LN may be involved
causes of lymphadenitis
mycobacteriumbacteriafungiparasites–Brugia (filariasis)cytology, biopsy, culture
persistent inflammatory edema from poor lymph drainage can lead to what….
mesenchymal cell proliferation which may cause irreversible thickening of skin and subcutis
lymph edema physiology
occurs when interstitial P increases as a result of a fluid imbalance btwn capillary filtration and lymphatic return1. high lymphatic load2. decreased plasma oncotic P3. increased vascular permeability4. obstruction of lymph system
histologic findings in chronic lymphedema
- thicken BM of lymph vessels2. increase macros, fibroblasts3. increase amounts of collagenall of which may lead to fibrosis of SQ with chronic lymph edema
4 most common skin tumors in cats vs dogs
DOGSMCT, ST sarcoma, perianal adenoma, SCCCATSSCC, basal cell tumors, MCT, ST sarcoma
types of round cell tumors (6)
- lymphoma2. malignant histocytosis3. TVT4. MCT5. plasma cell tumors6. histocytomas
papilloma
BENIGNcauliflower likeassociated with DNA viral causetransmission can occur directly and indirectlymay resolve within 3 months excision or cryotherapy is size or location is causing a problem
SCC
most common skin neoplasm in catsmalignantsolar exposure– non pigmented skin is most commonly affected precursor –actinic keratosispapilloma virus relationship potential can be proliferative or erosiveassociated with mutation in p53 tumor suppressor gene
name of multi centric SCC in situ in cats
Bowenoid in situ carcinoma in cats (RARE)multifocal crusted plaques anywhere on body
most common location of SCC in dogs vs cats
dogs: subungual, digital, scrotum, legs, anuscats: pinnae, eyes, nose,
risk of white cats and SCC
white cats have a 13x higher risk compared to cats with other coat colors
MST of SCC following pinnectomy or nosectomy in cats
673 days
therapeutic options for SCC
- cryotherapy (small early lesions, multiple tx, no histo dx)2. plesiotherapy3. radiation therapy (not evaluated in conjunction w sx)4. photodynamic therapy5. chemotherapy (NOT as sole tx, intralesional possible6. immunomodulatory therapy (Imiquimod cream–75% develop new lesions)7. SURGERY (aggressive)
redefine basal cell tumors
second most common skin tumor in catsredefined as trichoblastomagenerally benign
perianal gland adenoma
3rd most common cutaneous tumor in DOGSperianal hepatoid gland tumorsarise from modified sebaceous glands in dermis surrounding anuspredominately SEX HORMONE DEPENDENT (stimulated by androgens, suppressed by estrogens)INTACT MALES presdisposed90% cured with castration
perianal gland adenocarcinoma
NOT hormone dependentrarefaster growth rate, mets occur, more invasive
canine anal sac adenocarcinoma (apocrine gland adenocarcinoma of the anal sac)
older female dogs, no hormone dependencemetastatic rate 36-96% (regional sublumbar nodes)paraneoplastic hyperCa 27%complete excision difficult—follow up with chemo (mitoxantrone) and/or radiation therapy
percentage of incidental diagnosis of anal sac adenocarcinoma in dogs
up to 39% found as incidentalRECTAL!
MST with surgery alone (with or without lymphadenecomy)
8-16 monthsvs 32 months with surgery, mitoxantrone chemotherapy and radiation therapy!dogs with large tumor >10cm2 had shorter survival (292d) than dogs with smaller tumors (584d) in one study
how does feline anal sac adenocarcinoma differ from dogs
POOR PROGNOSISeven with surgery only 3 months (surgery not recommended)hyperCa is NOT a general feature
ST Sarcoma
2nd most common cutaneous tumor in dogsmesenchymal, slow growing, locally invasive, met slowlydo not exfoliate well (only correct on cytology 70%)
rate of mets for ST sarcoma in dogs
depends on gradegrade 1,2 < 13%grade 3 > 40%
most important prognostic factor of local recurrence for ST sarcoma
CLEAN SURGICAL MARGINS (and size in cats)recommend 2-3 cm and one fascial plane deep
recurrence of ST sarcoma after RE-excision and after radiation therapy
15-17%
MST ST sarcoma with surgery (incomplete) and radiation therapy
incomplete sx + radiation 2270dradiation after marginal or debunking results in good clinical outcome
in cats with ST sarcoma MST
12-20 monthsSIGNIFICANTLY LONGER IF COMPLETE (>16 months) vs incomplete (9 months)
ST sarcoma grade dependent recurrence after marginal excision
grade 1 7%grade 2, 3 34%median time to recurrence 12 monthsrecommend eval q 3 months for the first year and every 6 months after that
histologically LOW grade but biologically HIGH grade fibrosarcomas
oral tumor of dogsgaurded prognosiscan affect young dogslocally very invasive
hemangiopericytomas act like PNST (all ST sarcomas) but what staining differentiates the two
hemangiopericytoma—NEGATIVE vimentinPNST—POSITIVE vimentin
feline injection site associated sarcoma
associated with administration of INACTIVATED vaccines with an increased risk 2-5x for rabies and FeLV vaccines also linked to multivalent vx, long term penicillin injxn, methylpred injxn, and non absorbable suture
distinct differences btwn injection site sarcomas in cats versus other ST sarcomas
- more malignant biological and histological features2. inflammatory component present
recommendations for vaccination sites in cats
DISTALrabies–right hindFeLV–left hindother multivalent–right front
recurrence of injection site associated sarcoma with marginal excision
70%MUCH HIGHER than ST sarcoma (7-34% depending on grade)median time til recur sign longer is specialist (274 d) vs rDVM (66d)
Phelps et al JAVMA 2011 conclusions on recurrence and metastatic rate of injection site sarcomas treated with 5 cm and 2 fascial planes deep exicison
14% recurr20% metastatic ratecats without recurrence and without mets survived longerrecur and mets were significantly associated with less survival
types of lipomas
benign lipoma (may or may not be inter muscular)liposarcoma (can met, locally invasive)infiltrative lipoma ( invasive–no capsule; but do not generally met)
reported local recurrence rate following surgery for infiltrative lipomas
36-50%in average time of 239 daystherefor slow growth combined with old patient = favorable prognosis
stain to ddx liposarcoma from other ST sarcomas
oil red O stain
cutaneous HSA in dogs
high metastatic ratecutaneous is better than SUBcutaneous which is better than IM hemangiosarcomacomplete excision followed by adjuvant chemotherapy
feline fibropapilloma
feline sarcoidvirus associatedyoungrural or barn catscontact with cattleinfiltrative but not metastatic
anatomy of dog vs cat mammary chain
DOG—5 pairs (cr and cd thoracic, cr and cd ab, inguinal)CAT–4 pairs (cr and cd thoracic, cr and cd ab)–lack inguinal
blood supply of mammary glands
mainly originates from lateral and internal thoracic arteries AND external pudendal artery1. 3 cranial glands:cr superficial epigastric, lateral internal thoracic, branches of intercostal arteries from internal thoracic artery2. 2 caudal glands: cd superficial epigastric (originates from ext pudendal artery) and deep branches of cranial abdominal and deep circumflex iliac arteries
lymph nodes of the mammary chain in dogs
DOGS: cr and cd thoracic mammary glands–>axillary LN (+/- superficial cervical LN, sternal LN)cr and cd abdominal mammary glands –> axillary and inguinal LNcd abdominal mammary gland–>medial iliac LN, popliteal LNinguinal mammary gland –> inguinal LN, medial iliac LN, +/- popliteal LN
lymph nodes of the mammary chain in cats
CATS: cr and cd thoracic mammary glands–>axillary LN +/- sternal LNcd thoracic mammary gland –> inguinal LNcr abdominal mammary gland –> axillary LN +/- sternal LNcr and cd abdominal mammary glands –> inguinal LNcd abdominal mammary gland–>medial iliac LN, popliteal LN
what is the risk of mammary cancer in dogs in terms of estrus cycle
before first estrus 0.5%after first estrus 8%after second estrus 26%
T/Fcanine mammary tumors are hormone dependent, however, loss of hormone dependency frequently occurs in malignant mammary tumors
TRUEestrogen and progestin receptor expresssion is significantly lower in malignant mammary tumors vs benign and normal mammary tissueinflammatory carcinomas (the MOST malignant mammary tumor type) were estrogen receptor NEGATIVE
genetic factors involved in mammary tumorigenesis
mutations p53overexpression HER-2 (protooncogene)overexpression COX2
inflammatory carcinoma of mammary glands
most malignant formmets vary 8-100%55% bilateral chains affectedhisto: malignant mammary type WITH CHARACTERISTIC INVASION OF DERMAL LYMPHATICSsurgery not recommendedpiroxicam may extend MST
T/Fin female dogs the type of surgery does not seem to affect the prognosis as long as complete excision is achieved
TRUE
different surgeries for mammary tumors
- lumpectomy–nodulectomy; small <0.5cm, benign, marginal excision2. simple mastectomy–mammectomy, 1 gland removed but achieves 2-3 cm margins, difficult if glands are confluent3. regional mastectomy–en bloc of gland 1-3 and 3-5 glands; INCLUDE inguinal LN if possible4. chain mastectomy–mets based on lymph drainage is unpredictable, if multiple tumors, third gland, or large take chain.
T/F58% of dogs develop new tumor in the remaining ipsilateral glands after regional mastectomy for one mammary tumor
TRUEand new tumor is likely to be malignant if located near the previously excised malignant one
T/Fthe risk of malignancy increases with increasing size of mammary tumor
truemalignant tumors 4.7 cm diameterbenign tumors 2.1 cm diameterresected smaller tumors have a longer survival
recurrence rates of mammary tumors in dogs with and without evidence of LN mets
with LN mets recur 80% within 6 mowithout LN mets recur < 30% within 2 yrs
what is the benign differential for a feline mammary mass
fibroadenomatous hyperplasiaGOES AWAY WITH OHE
where do mast cells originate
CD34+ cells from the bone marrow
relative risk of boxers having MCT
16.7 x
percentage of canine MCT affected by c-kit mutations
15-40%
Darrier sign
edema, erythema, inflammation of the tumor and surrounding tissueslocal changes are associated with a worse prognosis
MST after surgery of MCT based on grade
- > 1300 days2. 800 days3. 300 days
negative prognostic indicators for MCT
- grade 32. MM location
locations associated with poorer prognosis with MCT
preputialscrotalcanine muzzlevisceral
feline MCT
50-90% well differentiatedregress spontaneouslybehave more benignlybut poorly differentiated behave malignantly
most common splenic disease in cats
MCTvisceral MCT is more common in cats than dogs and is NOT associated with cutaneous MCT in cats; mets are common with visceral formsdid not have ckit mutations
top three intestinal tumors in cats
- LSA2. AdCa3. MCT
with malignant melanoma, what is an important prognostic factor
LOCATIONhaired–act benign–favorable pxoral, MM, nail bed–malignant–guarded px
how does the melanoma vx work
xenogeneic (human, murine) DNA vaccineencodes for human, murine tyrosinasesand then Ab are made against tumor tyrosinases (antityrosinase Ab) potentially therapeutic (immunomodulating)
most common nail bed tumors in dogs
SCC (blk labs and poodles)malignant melanoma (guarded px, Scottish Terrier)55% malignant25% inflam16% benignbone lysis 75%
