Derm - neoplastic skin diseases

Question 1

How are skin tumours classified?

Answer 1

Epithelial
Spindle cell
Round cell
Melanocytic
Metastasis to skin

Question 2

What causes papilloma?

Answer 2

Papillomavirus - DNA virus

Question 3

How do papilloma viruses grow?

Answer 3

Grow out of the skin - exophytic

Question 4

What changes to the epithelium do papilloma cause?

Answer 4

Hyperplastic/keratotic squamous epithelium
Have a fibrovascular stalk

Question 5

What cause is associated with squamous cell carcinoma?

Answer 5

UV light

Question 6

Where do squamous cell carcinoma tend to affect?

Answer 6

Eyelids, ear tips, unpigmented thin hair areas

Question 7

What changes to the epithelium do squamous cell carcinoma cause?

Answer 7

Invasive cords to squamous epithelium
Keratin pearls/aggregates form
Scirrhous - fibrous tissue forms around the mass

Question 8

What can cause digital squamous cell carcinoma in cats?

Answer 8

Pulmonary metastasis

Question 9

What are infundibular cysts, infundibular keratinising acanthoma and trichoblastoma examples of?

Answer 9

Tumours of the hair follicles

Question 10

What to tumours of the hair follicles mostly present as?

Answer 10

Benign, slow growing masses in older animals

Question 11

What is the most common tumour of the hair follicle in dogs?

Answer 11

Infundibular cyst

Question 12

What are the features of an infundibular cyst?

Answer 12

Marked thickening of the epithelial lining of the hair follicle

Question 13

What are the features of a keratinising acanthoma in dogs?

Answer 13

Keratin protrudes out of the opening of the hair follicle
Complete branching of the wall

Question 14

What are some sebaceous gland masses?

Answer 14

Sebaceous hyperplasia
Sebaceous adenoma
Sebaceous adenocarcinoma

Question 15

What is the most common sebaceous gland mass?

Answer 15

Sebaceous hyperplasia

Question 16

What is a Sebaceous hyperplasia?

Answer 16

Benign proliferation of normal sebaceous glands

Question 17

What is an example of a Sebaceous adenoma?

Answer 17

Meibomian gland adenoma

Question 18

Where is a meibomian gland adenoma located?

Answer 18

In the eyelid

Question 19

What is another name for a hepatoid gland hyperplasia?

Answer 19

Circumanal gland hyperplasia/adenoma

Question 20

What signalment of animal are circumanal gland hyperplasia/adenoma found in?

Answer 20

Middle age/older intact male dogs (partially castration responsive)

Question 21

What kind of tumour is more common in anal sac apocrine gland tumours?

Answer 21

Adenocarcinoma rather than adenoma
More likely to be malignant

Question 22

What are the main features of anal sac apocrine gland tumours? What side effects do they cause?

Answer 22

Metastatic, infiltrative
Cause pseudo-hyperparathyroidism
Cause Paraneoplastic hypercalcaemia

Question 23

What structures can mesencymal cell tumours affect?

Answer 23

Fat
Fibrous tissue
Muscle
Blood vessels
Bone
Cartilage

Question 24

What is fibrous tissue?

Answer 24

Collagen - fibroblasts

Question 25

What animal are fibromas mostly found in?

Answer 25

Cats

Question 26

What is the appearance of fibromas?

Answer 26

Well circumscribed bundles and whorls of collagen with uniform fibroblasts

Question 27

What animal are fibrosarcomas usually found in?

Answer 27

Dogs Young and old cats

Question 28

What differs between young and old cats with fibrosarcomas?

Answer 28

Young cats - multicentric fibrosarcomas from FeLV Old cats - solitary fibrosarcomas from injection sites

Question 29

What is the appearance of a fibrosarcoma on histopath?

Answer 29

Pleomorphic cells with mroe mitotic figures and giant cells Rapid growth, infiltrative

Question 30

Are fibrosarcomas metastatic?

Answer 30

No

Question 31

What are sarcoids? What causes them?

Answer 31

Fibrous tissue tumours in horses caused by bovine papilloma virus

Question 32

What is the appearance of sarcoids on histopath?

Answer 32

Hyperplastic epidermis Whorls and bundles of collagen/fibroblasts Usually low mitoses Local infiltration

Question 33

Are sarcoids metastatic?

Answer 33

No - local infiltration only but may recur after removal

Question 34

What are histiocytic tumours?

Answer 34

Tumours from cells that infiltrate the skin

Question 35

What is the most common dog skin tumour?

Answer 35

Histiocytoma

Question 36

What is a histiocytoma?

Answer 36

Benign rapidly growing 'strawberry button' tumour in young dogs that can spontaneously regress

Question 37

What makes up a histiocytoma?

Answer 37

Dendritic langerhans cells Cytotoxic lymphocytes infiltrate at the base

Question 38

Will histiocytomas recur after excision?

Answer 38

No

Question 39

What animal do mast cell tumours affect?

Answer 39

Dogs - bad, more common Cats - benign, rarely metastasise

Question 40

Do mast cell tumours metastasise?

Answer 40

Yes - local infiltration and metastasis to local lymph nodes

Question 41

What is the appearance of mast cells on histopath?

Answer 41

A sheet of mast cells with varying differentiation and depth of infiltration Will see eosinophils (pink) and lymphoid aggregates

Question 42

What can mast cells cause?

Answer 42

Paraneoplastic effects - histamine

Question 43

What are the two forms of melanocytic tumours?

Answer 43

Melanocytoma - benign Malignant melanoma

Question 44

What animal is a benign dermal melanomas found in?

Answer 44

Dogs

Question 45

What do benign dermal melanomas look like grossly?

Answer 45

Pigmented solitary nodule of haired skin

Question 46

What do benign dermal melanomas look like on histopath?

Answer 46

Contain dermal infiltrate and epidermal nests with junctional activity Melanophages present

Question 47

What animal are malignant melanomas found in?

Answer 47

Dogs

Question 48

Where are malignant melanomas found?

Answer 48

Oral Digital Scrotal

Question 49

Can malignant melanomas metastasise?

Answer 49

Yes - not always a poor prognosis but may metastasise to local lymph nodes or lungs

Question 50

What do malignant melanomas look like on histopath?

Answer 50

Hard to distinguish from benign ones but pleomorphic, mitoses Invasiveness Not more pigmented - may be amelanotic

Question 51

What animal gets melanomas quite a lot?

Answer 51

Horses - especially grey ones older than 6

Question 52

What is it called when horses have multiple melanomas?

Answer 52

Melanomatosis

Question 53

Are equine melanomas malignant?

Answer 53

They can be, but they are slow growing