Lumps and Bumps

Question 1

What is botryomycosis?

Answer 1

NOT fungal!

• also called bacterial granuloma, staphylococcal pseudomycetoma
• > nodules and non-healing wounds

Question 2

What are nodular lesions usually caused by?

Answer 2

• cutaneous neoplasia
• inflammatory process (diffuse or nodular inflam pattern, or panniculitis) usually granulomatous (may be sterile [FB] but usually infection [bacteria/mycobacteria/viral/funghi/parasites])
• trauma
• depositional disease eg. amyloidosis

Question 3

Diagnositcs for nodular lesions? Exception?

Answer 3

• histology (biopsy)
• cytology (FNA)
• macerated tissue culture
  > exception sarcoids where invasive procedures may stimulate further invasion

Question 4

What is panniculitis?

Answer 4

• inflam subcutaneous fat and connective tissue

- usually infective

Question 5

Which neoplasia affects the interfollicular epithelium?

Answer 5

• papilloma

- squamous cell carcinoma

Question 6

What 4 main sites give rise to skin neoplasia?

Answer 6

• epithelium
• mesenchyme
• round cells (MCT, histiocytes, lymphocytes)
• mets

Question 7

What may appear like a nodule in horses but isnt?

Answer 7

wheals/hives - will be oedematous (pitting)

Question 8

3 most common skin neoplasia in dogs and cats?

Answer 8

> dogs 
- hepatoid gland adenoma (perianal, testosterone dependant)
- sebaceous adenoma
- trichoepithelioma 
> cats
- basal cell tumour
- SCC
- aprocrine duct/gland/ceruminous gland adenoma

Question 9

What type of neoplasm will regress on its own?

Answer 9

Histiocytoma

Question 10

What may epithelial cells in the skin be ‘destined’ to become?

Answer 10

• basal keratinocytes -> squames
• inner and out root sheaths of follicle
• adnexal glands and ducts

Question 11

Are majority of epithelial tumours malignant?

Answer 11

No - mostly benign

Question 12

3 tumours of the epidermis

Answer 12

• papilloma (warty, young dogs)
• inverted papilloma
• SCC (white cats face tips, keratin pearls/swirls on histo)

Question 13

What types of tumour show adnexal differentiation?

Answer 13

• hair follicle
• sebaceous (+ modified sebaceous) glands
• sweat (+ modified) glands

Question 14

5 hair follicle tumours

Answer 14

• infundibular keratinising acanthoma
• tricholemmoma
• trichoblastoma (=basal cell tumour)
• trichoepithilioma
• pilomatricoma

Question 15

3 tumours of sebaceous glands/modified sebaceous glands?

Answer 15

• sebacious hyperplasia/adenoma/epithelioma/adenocarcinoma
• hepatoid gland adenoma/adenocarcinoma
• meibomian gland adenoma/epithelioma/adenocarcinoma

Question 16

4 tumours of sweat glands/modified?

Answer 16

• apocrine gland adenoma/ductal adenoma/adenocarcinoma
• eccrine (atrichial) adenoma/adenocarcinoma
• ceruminous gland adenoma/adenocarcinoma
• anal sac adenoma/adenocarcinoma

Question 17

Which tumours do not have squamous or adnexal differentiation?

Answer 17

• basal cell tumour (tichoblastoma)

- basal cell carcinoma

Question 18

Which species has a higher risk of malignant skim neopasia?

Answer 18

Cats (dogs usually benign)

Question 19

5 types of mesenchymal tumour

Answer 19

• fibrous
• vascular/perivascular
• muscle
• neural and pernineural
• lipcytic

Question 20

Clinical presentation of mast cell tumours?

Answer 20

• varies massively!!
  -single/multiple
• small/large
• well demarcated/imfiltrive
• firm/soft
• ulcerated/epithelialised
• oedematous/inflam
• pigmented/non-pigmented
  > fluctuant swelling and erythema should ^ suspicion
  > affect dermis and subcutis
  > usually back half of body (perineum, dital limbs, perpuce)
  > Boxers, pugs, weimeranas predisposed
• concurrent signs due to histamine, heparin and other vasoactive mediator release: bleeding disorders, immune-mediated thrombocytonpaenia, GI ulceration

Question 21

Are MCT considered benign?

Answer 21

Should be considered potentially malignant

Question 22

Diagnostics

Answer 22

• cytology
• imaging
• buffy coats + BM aspirate
  > difficult to interpret

Question 23

Tx MCT

Answer 23

Standard neoplasia surgery, chemo, radiation

• surgery gold stand woith nonode involvement
• intermediate 2cm margins and one deep facial plane
• some dirty margins will not regrow