75. Benign mesenchymal tumors

Question 1

Fibroma

Answer 1

 Tumour of fibrocytes
 Usually in dermis or subcutis
 Well-demarcated, unencapsulated
 Durum („firm”) és molle („soft”) type
 Frequently mixed with other tissue types (leiomyofibroma, fibroadenoma, fibromyxoma, etc.)

Question 2

Most frequent tumour of horses

Answer 2

Equine sarcoid

Question 3

Myxoma

Answer 3

Gelatinous connective tissue, fibroblast/fibrocyte origin
Mostly in subcutis
Non-encapsulated, not well-demarcated

Question 4

Lipoma

Answer 4

Benign tumour of adipocytes
Very high incidence (especially dogs)
In subcutis, borders are indistinct
Rare, but important: hemangiosarcoma, mast cell tumour inside the lipoma!

Question 5

Chondroma

Answer 5

Benign tumour of chondrocytes
Mostly hyalin cartilage
Primary bone origin
Larynx, trachea
Slow growth, can cause bone deformity

Question 6

Osteoma

Answer 6

Neoplasm of bony tissue (compact or trabecular)
Usually soliter, affects the bones of head

Question 7

Osteochondroma

Answer 7

Bony proliferation capped with cartilage, endochondral ossification in the bone
Young dogs, horses
Cat osteochondromatosis
▪ FeLV, FeSV role?
▪ Differs from dogs’ and horses’ disease
▪ Progressive growth, different localisation