Tumors of the skin and SQ tissue Flashcards

Question

Sebaceous Hyperplasia, Sebaceous Adenoma, Sebaceous Ductal Adenoma and Sebaceous Epithelioma Behaivour? Mean age? Breeds at risk? Common location? Treatment?

Answer 1

Very common in dogs and rare in cats. Benign, lymphatic metastasis has been reported; therefore, thought as low-grade malignancies rather than absolutely benign. Mean age is 7 to 13 years, a predilection for females have been reported, breeds at increased risk for hyperplasia are miniature schnauzers, beagles, poodles and cocker spaniels; and for tumors are Coonhounds, Nordic breeds and some terriers. Most common locations are limbs, trunk, and eyelids. Treatment is surgery (unless metastasis), but recurrence have been reported.

Answer 2

Uncommon tumors in dogs and cats, that can behave as low-grade malignancies characterized most commonly by local infiltration and metastasis beyond the lymph node found only in one report (to bones, skin and lungs; Case et al, JAVMA 1963). A predilection for intact male dogs has been reported, Breeds at increased risk are Cavalier King Charles spaniel, cocker spaniel, and terrier breeds. Most common locations are the head and neck in dogs and the head, thorax, and perineum in cats. Treatment is surgery.

Answer 3

Common tumors in dogs, uncommon in cats. May be fluid filled or firm on palpation. Most common location in cats is the head. Treatment is surgery.

Answer 4

relatively uncommon in dogs and a bit more common in cats (1.1 and 3% of all skin tumors, respectively). Two main studies looking at these tumors are available (Simko et al, Can Vet J 2003 and Kalaher, Vet Rec, 1990), one reported 40/44 apocrine gland tumors in dogs and 8/10 in cats to be malignant. Most commonly seen as solitary nodular lesions (indistinguishable from benign counterparts), but an “inflammatory” more diffuse and erosive form also exists. Local invasion is common (66% noted invasion of the capsule, and 11% and 22.5% noted vascular and lymphatic invasion), but the rate of distant metastasis is reported as low (2% to the lungs, contrasts high metastatic rate of anal sac apocrine gland carcinomas. Mean age in dogs is 9 years and in cats is from 6-17 years, breeds at increased risk are Golden retrievers and Treeing Walker coonhounds (no breed predilections in cats have been reported). Most common locations for dogs are the front legs, and for cats are the head, limbs, and abdomen. Treatment is wide surgical resection (if no metastasis, 4% recurrence rate), beyond this no information is available.

Answer 5

Tumors of the sweat glands of the foot pads. Rare in dogs and cats, and no reports on clinical behavior or outcome are available. Treatment is wide surgical excision.

Answer 6

Merkel cells are thought to be part of the mechanoreceptor system in the skin. These are highly malignant tumor in humans (associated with Merkel cell polyomavirus infection), but generally have a more benign clinical behavior in pets, although all of our information is based on isolated case reports. Although some of these reports do document instances of multiple recurrence and widespread metastasis to the lungs, abdomen and skin. Molecular evaluation of 2 dogs noted expression of β-catenin, E-cadherin (usually lost on more malignant human variants in people), and c-KIT (da Costa, Vet Dermatol, 2010). Treatment is wide surgical excision, beyond this no information (including response to c-KIT-TKi) is available (one report of a dog with multiple lesions and metastatic disease treated with various chemotherapeutics, and had an OS of 8 months; Joiner et al, Vet Pathol 2010).

Answer 7

Present as multiple firm, haired masses. On histopathology these nodules are dense, irregular collagen. They typically do not result in clinical problems. Breeds at increased risk are GSD and Alsatians; one case report of a non-lethal version of this syndrome was overserved in an Australian cattle dog (Gardiner, et al, Vet Pathol, 2008). Treatment is wide surgical excision in patients that are doing otherwise well. However, Most of these dogs will die from renal failure or progressive renal cystadenocarcinoma, in ~3 years.

Answer 8

Modified apocrine glands found in the external ear canal Chronic otitis or partial deafness Mitotic index of \>3 (Bacon et al, JSAP 2003), extension beyond the ear canal (“stage” see box), presence of neurologic signs, and histology of SCC (over CGA).

Answer 9

Benign tumors, typically exophytic, pedunculated and sometimes ulcerated. Dogs is 9 years old, in cats adenomas present in younger patients than the malignant variants Breeds at increased risk are cocker spaniels and poodles. Treatment is surgery

Answer 10

Most common malignant tumors of the ear canal in both dogs and cats These cancers can be very invasive locally and have important metastatic potential, thus a CT to assess local extension and full staging are recommended before planning definitive therapy. Cocker spaniels and GSDs The treatment of choice is complete surgical resection- TECA or a lateral bulla osteotomy, which are associated with significantly lower rate of recurrence than less aggressive techniques such as lateral ear canal resections (a study in dogs by Marino et al, JAAHA 1993 reported a DFI \>36 months vs 4 months respectively; while a study in cats by Marino et al, JAAHA 1994 reported a DFI of 42 months vs 10 months respectively). Radiation therapy also appears to be an effective treatment modality, with a reported PFS of 39.5 months after therapy (orthovoltage, 48 Gy in 12 4-Gy; Theon et al, JAVMA 1994). Evidence from various studies seem to suggest that long-term survival is possible with appropriate local therapy.

Answer 11

SCC are the most common malignancy of the digits in dogs (47%, with 3% being multi-digital, mostly in black-big-dogs, e.g., Rotties, black labs, giant schnauzers), followed by melanomas (24%, mostly in Scotties) and STS (13%) These tumors can invade bone (SCC=80%, melanomas=21%) and metastasize (SCC=9% noted at diagnosis and 23% later, melanomas=28% at diagnosis and 39% later), thus appropriate staging is indicated. For SCC of the digit, 1 and 2-year survival rates after surgery range from 50% to 83% and 18% to 62% respectively (subungual \> other sites). Digital melanoma reported similar survival numbers, with 42% to 57% alive at 1-year post surgery and 13% to 36% at 2-years; the addition of adjuvant immunotherapy with the HuTyr vaccine reported an OS=476 days and a 63% and 32% 1 and 2-year survival rate after surgery (n=57, surgery and vaccination Manley et al, JVIM 2011).

Answer 12

One study on digital tumors in cats (n=60, mostly on the front paws, some affecting multiple digits; Wobeser et al, Vet Pathol 2007) reported almost equal numbers for SCC (25%), fibrosarcoma (23%) and adenocarcinomas (22%). ## Footnote Staging is also indicated in cats, especially in SCC as up to 87.5% of digital tumors were suspected to represent metastasis from primary lung carcinomas in one study (n=64 cats, “lung-digit syndrome”, MST=only 4.9 weeks, Van der Linde et al, Vet Q 2000), and also on melanomas (one study, n=5 cats only; mets=4, Luna et al, J Feline Med Surg, 2000). Median survival times for cats with SCC ranged from 10 to 29 weeks, and for the five cats with melanoma ranged from 0 to 577+ days.

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Tumors of the skin and SQ tissue Flashcards

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