Equine oncology Flashcards
Where do neoplasias most often affect horses? What are they?
- Skin (90%) =
- Sarcoid
- SCC
- Papilloma
- Melanoma
- Mast cell tumour
What breeds are predisposed to different cancers?
- Lipizzaner = melanoma
- Shire + Clydesdale = ocular SCC
What are other risk factors?
- Age
- Sex - male = penile SCC (+ SCC in other locations)
- Location + management - UV exposure = SCC
What are signs of cancers?
- Depend on tissue type + functionality - skin vs hormone secreting
- Size = e.g. granulosa cell tumour
-small = no signs (non-functional)
-large = colic (space occupying lesion)
-Very large = ruptured ovarian artery + haemoabdomen - Number = multiple tumours = more problems
- Longer the duration = more likely to metastasize
What are paraneoplastic syndromes?
- Diseases or combination of signs that arise as a direct consequence of a tumour but not deriving from the simple physical presence of the tumour
What are the 4 groups of paraneoplastic syndromes?
- Mucocutaneous and skin syndromes = paraneoplastic pemphigus, pruritus
- Neurological syndromes
- Haematological syndromes = anaemia, polycytaemia, granulocytosis
- Endocrine and metabolic = cachexia, hypercalcaemia, hypertrophic (pulmonary) osteopathy (Marie’s disease)
How are neoplasias diagnosed?
- History
- Physical exam (+rectal)
- Tests =
- Biopsy, tumour markers
- imaging (US, Rx, Endoscopy, CT, MRI)
- Haematology, biochem, urinalysis
What are different cancer therapies?
- Ablative =
- Surgery
- Laser / diathermy
- Cryotherapy
- Hyperthermia - Cytotoxic =
- Chemo
- Radiotherapy
- Phototherapy
- Electrochemotherapy - Biological =
- Immunotherapy
- Vaccines
- Cytokinetherapy
- Gene therapy
What is the most common haematopoietic neoplasia in horses + the different forms?
- Lymphoma
- Multicentric
- Alimentary
- Mediastinal, thoracic / thymic
- Cutaneous
What is multicentric lymphoma? Who does it effect? Signs? Dx? Tx? Prognosis?
- Mature young horses: 4-12y
- Involvement of many organs and metastasis common
- Signs: weight loss, depression, ventral oedema, recurrent fever
- Sings are vague so cases tend to present when advanced
- Diagnosis: cytology or biopsy
- Treatment: surgical removal if solitary lesions, chemotherapy?
- Prognosis: depend on stage of disease
What is alimentary lymphoma? Who does it affect? Signs? Dx? Tx? Prognosis?
- 20% of lymphoma cases and most common intestinal neoplasia
- Older horses: >12y
- Signs: malabsorption, weight loss, colic
- Diagnosis: cytology (peritoneal fluid), biopsy
- Treatment: surgical removal if solitary lesions, chemotherapy?
- Prognosis: depend on stage of disease, typically poor
What is mediastinal, thoracic or thymic lymphoma? Who does it affect? Signs? Dx? Tx? Prognosis?
- Most common thoracic neoplasia
- Horses of all ages
- Signs: weight loss, depression, ventral and limb oedema, pleural effusion
- Diagnosis: cytology (pleural effusion), biopsy
- Treatment: palliative
- Prognosis: hopeless
What is cutaneous lymphoma? Who does it affect? Signs? Dx? Tx? Prognosis?
- Rare
- Older horses
- Signs: Subcutaneous and cutaneous nodules
- Diagnosis: biopsy
- Treatment: removal if solitary masses
- Prognosis: Less aggressive than the other forms, may become static for years or even regress
What is haemangiosarcoma? Who does it affect? What are the signs?
- Uncommon, highly malignant tumour of vascular endothelium
- Middle age to older horses (but all ages possible)
- No breed or sex predilection
- Signs: depends on body system affected
– Respiratory and musculoskeletal most common
– Haemorrhage: haemoabdomen, haemothorax
How is haemangiosarcoma diagnosed? Tx? Prognosis?
- Dx = cytology, biopsy
- Tx = limited + palliative
- Prognosis = very poor
