21. Disorders of the mammary gland – tumours (diagnosis of tumours, clinical classification in bitch and queen – staging)

What is the second most common tumour in female dogs?

Mammary gland tumours

What percentage of mammary gland tumours are benign in dogs?

50%

What is the third most common tumour in female cats?

Mammary gland tumours

What percentage of mammary gland tumours are adenocarcinomas in cats?

80%

Which hormones influence the development of mammary gland tumours?

Oestrogen and progesterone

What factor in feline birth control can increase the risk of mammary tumours?

Birth control pills

What are some risk factors for mammary gland tumours?

Age >6 years, being unspayed, obesity, history of pseudopregnancy

Which mammary glands are more at risk in bitches?

Caudal mammary glands (M4-5)

What is the most effective way to reduce the risk of mammary tumours in bitches?

Spaying after the first heat

What is the effect of spaying after 3-4 heats on mammary tumour risk?

No significant reduction in risk

What are some types of mammary gland tumours in dogs?

Carcinoma, sarcoma, carcinosarcoma, benign adenoma

What are some types of mammary gland tumours in cats?

Carcinoma, sarcoma, mixed mammary tumours, adenocarcinomas

What are the clinical signs of benign mammary tumours?

Small, circumscribed masses

What are the clinical signs of malignant mammary tumours?

Rapid growing, ill-defined boundaries

What is the typical appearance of the cut surface of a mammary tumour?

Lobulated, grey-tan and firm, possibly with fluid-filled cysts

What are the clinical signs of inflammatory mammary carcinoma?

Rapid, multiple, firm, warm, oedematous, red masses

Is surgery recommended for inflammatory mammary carcinoma?

No

What treatments can be considered for inflammatory mammary carcinoma?

NSAIDs and antibiotics, with re-evaluation after the heat cycle

How are mammary gland tumours diagnosed?

History, palpation of glands and lymph nodes, lung X-ray, USG, bloodwork, FNA, biopsy

What information should be included in the history for diagnosing mammary tumours?

Use of progestogen drugs, history of pseudopregnancy, oestrus cycle, time of spay

What is the TNM system used for?

Staging tumours

What does 'T' in the TNM system refer to?

Tumour size

What does 'N' in the TNM system refer to?

Lymph node status

What does 'M' in the TNM system refer to?

Metastasis

What does T0 mean in the TNM system?

Tumour cannot be found

What does N0 mean in the TNM system?

No cancer in nearby lymph nodes

What does M0 mean in the TNM system?

Cancer has not spread to other organs

What do higher numbers in T (T1-T4) indicate?

Larger tumour size

What do higher numbers in N (N1-N3) indicate?

Cancer in more lymph nodes

What does M1 mean in the TNM system?

Cancer has spread to other organs

What diagnostic tool is important for checking for metastasis of mammary tumours?

Lung X-ray

Why is palpation of regional lymph nodes important in mammary tumour diagnosis?

To assess for potential spread of cancer.