Skin Tumors

Question 1

What is squamous cell carcinoma? What is its development associated with?

Answer 1

locally invasive, slowly metastasizing, malignant neoplasm of keratinocytes

chronic sun exposure

Question 2

What clinical findings are associated with SCC in dogs and cats?

Answer 2

DOGS - most commonly found on digits, trunk, limbs, scrotum, lips, and anus

CATS - most commonly found on head (nasal planum, eyelids, oral cavity) and more rarely seen on the digits –> commonly secondary to primary pulmonary carcinoma

Question 3

What is a papilloma? What species are most commonly affected?

Answer 3

benign tumors caused by infection of epithelial cells by papillomavirus (incubation period of 1-2 months)

young dogs

Question 5

How do papillomas most commonly present? How do they develop?

Answer 5

smooth white papules, plaques, or verrucous cauliflower lesions found on the nose, conjunctiva, and haired skin

most regress in 3 months, but may persist up to 1 year

Question 6

What are lipomas? What clinical findings are most common?

Answer 6

benign adipocyte tumors common in dogs

soft, dome-like masses found on the thorax, abdomen, and proximal limbs

Question 7

How do sebaceous gland tumors act?

Answer 7

• BENIGN: sebaceous epitheliomas, sebaceous adenomas, sebaceous hyperplasia
• MALIGNANT: sebaceous adenocarcinoma (rarely metastasizes!)

dogs > cats

Question 8

What are mast cell tumors? What causes their development?

Answer 8

malignant rumors of dermal mast cells

P53 and c-KIT mutation

Question 9

What clinical findings are associated with MCTs in dogs and cats?

Answer 9

DOGS - firm to soft, papular to nodular to pedunculated, dermal or SQ, urticarial swelling most common on trunk perineum, and limbs

CATS - firm or soft, white to pink plaques to nodules most common on the head or neck

Question 10

What development is associated with MCTs in dogs?

Answer 10

gastric ulcers and coagulopathies due to mast cells granule release (histamine, heparin, etc)

Question 11

What are cutaneous histiocytomas? What clinical findings are associated?

Answer 11

benign reactive hyperplasia of Langerhans cells common in young dogs that typically regresses spontaneously in three months

single, well-circumscribed mass commonly found in head, pinnae, and limbs

Question 12

In what species are fibrosarcomas most common? What are 2 common causes?

Answer 12

cats > dogs

1. feline sarcoma virus (young)
2. vaccines - Rabies, FeLV

Question 13

What clinical finding is most commonly associated with fibrosarcoma?

Answer 13

dermal/SQ, irregular or nodular masses commonly found on the trunk, distal limbs, ear pinnae, or vaccination sites

Question 14

How do most basal cell tumors act? In what species are they most commonly found?

Answer 14

most are benign, but certain types (basosquamous, solid basal cell tumors) are aggressive

cats > dogs

Question 15

What clinical finding is associated with basal cell tumors?

Answer 15

solitary and well-circumscribed growth commonly found on the head, neck, and thorax, along with the planum and eyelids of cats

Question 16

What are 6 variable presentations of cutaneous lymphoma?

Answer 16

1. depigmentation and ulceration of MM
2. plaques
3. nodules
4. patches
5. erythroderma
6. hyperkeratotic and ulcerated footpads

Question 17

What is a common cause of fibrovascular papilloma (skin tags)? What species are predisposed?

Answer 17

trauma

large dogs

Question 18

What clinical finding is associated with fibrovascular papilloma (skin tags)?

Answer 18

firm, pedunculated growth most commonly found on bony prominences, sternum, and trunk