[B] 1.80 Malignant epithelial tumors

Question 1

Adenocarcinoma

Answer 1

Malignant tumour of glandular epithelial origin

• Differentiated: Glandular structure, varying shape & size
• Less differentiated: Solid sheets of cells, cellular and tissue atypia

E.g: Dog: ​Perianal gland adenocarcinoma

Question 2

Multicentric in situ carcinoma

Answer 2

Bowen-like disease

• Pre-invasive phase of an epithelial malignancy
• Disorientated atypical cells, marked dysplasia
• Skin: Bowen / multicentric in situ carcinoma

Question 3

Multicentric in situ carcinoma: Mammary gland

Answer 3

Intraductal & intralobular carcinoma

Question 4

Multicentric in situ carcinoma: Mucosa BM invasion

Answer 4

Early neoplasia

E.g Superficial gastric tumour

Question 5

Squamous cell carcinoma: Predisposition

Answer 5

• Extended UV-light exposure
• Lack of pigmentation
• Furless areas; Alopecia

Horse, cattle, dog, cat (Older animals)

Question 6

Locations for squamous cell carcinoma in the dog

Answer 6

• Head
• Abdomen
• Perineum
• Limbs
• Digits
• Nail-bed (Subungual carcinoma)
  
  • Slow growing, invasive, no metastasis
  • Less differentiated

Question 7

Squamous cell carcinoma: Histopathology

Answer 7

• Uncontrolled proliferation of neoplastic keratinocytes
• Invasion of BM
• Dermis
• Subcutis
• Solid sheets & nests of cells
• Trabecules
• Varying levels of differentiation towards squamous epithelium

Question 8

Basosquamous carcinoma

Answer 8

• Low grade malignancy
• Predominantly basal cell proliferation
• Multifocal packets of cells
• Dogs (but rare)

Question 9

Epithelial tumours without squamous epithelium or adnexal differentiation

Answer 9

• Basal cell tumour
• Basal cell carcinoma

Question 10

Basal cell tumour

Answer 10

• Benign
• Neoplastic cells similar to basal cells of epidermis
• Frequent in cats
• Well-circumscribed, intraderma/subcut.

Question 11

Basal cell carcinoma

Answer 11

• Low grade malignancy
• Frequent in cats
• Sometimes ulcerated, invasive
• Multilobular
• No metastasis

Question 12

Epithelial tumours with adnexal differentiation

Answer 12

• Follicular tumours
  
  • Trichoblastoma
  • Trichoepithioma

Question 13

Trichoblastoma

Answer 13

• Originates from the developing follicular epithelium
• Benign
• Frequent in dogs, head/neck area
• Many hisostypes

Question 14

Trichoepithelioma

Answer 14

• All 3 layers of the follicle are affected
• Frequent in dogs
• Back & thorax

Question 15

Give the Malignant epithelial tumours

Answer 15

• Adenocarcinoma
• Multicentric in situ carcinoma
• Squamous cell carcinoma
• Basosquamous carcinoma
• Basal cell tumour
• Basal cell carcinoma
• Follicular tumours
  
  • Trichoblastoma
  • Trichoepithlioma