Canine Mammary Tumors: Evaluation & Treatment

History of Present Illness A 9-year-old intact female Australian shepherd dog is brought to the clinic for evaluation and recommendations of treatment options fora mammary mass. The mass has been present for 8 months, and in the last 4 to 6 weeks it has doubled in size. The dog has been licking the mass, which is now ulcerated and bleeding. Otherwise, the dog is well. General: Bright, alert, and responsive

Skin: Mammary mass with ulcerated, bleeding skin; 3 additional smaller mammary masses and 4 soft, subcutaneous masses on trunk

HEENT: Noncontributory

Pulmonary: Noncontributory

Cardiovascular: Noncontributory

Gastrointestinal: Noncontributory

Genitourinary: Noncontributory

Musculoskeletal: Stiffness in gait

Neurologic: Noncontributory What could be the problem?

The Australian shepherd dog you described with a mammary mass presents a concerning case. Canine mammary tumors, which are what the mass could likely be, are common in dogs, especially in older, intact females. More than half of these tumors are benign mixed tumors, but a smaller percentage can be malignant, which can metastasize involving epithelial or mesenchymal components【13†source】.

The rate of growth of the tumor is an important aspect to consider. A rapid increase in size, as you've described, can be significant in determining the prognosis. For diagnosing mammary tumors, fine-needle aspirates are commonly used due to their simplicity, cost-effectiveness, and quick results. Additionally, palpating regional lymph nodes and thoracic radiographs are recommended to assess the extent of spread and check for pulmonary metastases【14†source】.

Surgical removal is the primary treatment for mammary tumors in dogs. The type of surgery, ranging from lumpectomy to radical mastectomy, depends on various factors, and there's no consensus on the best procedure. Chemotherapy has not been shown to be effective as an adjunct in these cases【15†source】.

Given the nature of this case - a rapidly growing, ulcerated, and bleeding mammary mass in an older dog - it's critical to consider the possibility of malignancy. Factors like diet, obesity, and genetics (such as mutations in BRCA1 and BRCA2 genes) have been associated with an increased risk of mammary gland tumors in dogs. These tumors can spread to regional lymph nodes and lungs, and a small percentage may lead to skeletal metastases【16†source】.

Immediate veterinary attention is required for a comprehensive evaluation and to discuss the best course of action, considering the dog's age, health status, and the characteristics of the mass. Your veterinarian can guide you on the diagnostic procedures and treatment options, including the possibility of surgery.

Past Medical History Medical history: Arthritis, cystic endometrial hyperplasia, mammary mass for approximately 8 months, no pregnancies in past 5 years

Surgical history: None

Medications: Monthly prophylaxis for fleas and internal parasites

Allergies: No known drug allergies.

Family history: Not known

Social history: Patient lives in a household with one cat What would be the next step?

Given the Australian shepherd's medical history of arthritis, cystic endometrial hyperplasia (CEH), and a long-standing mammary mass, the next steps should involve a thorough veterinary evaluation to address these multiple health concerns.

1. Cystic Endometrial Hyperplasia (CEH): This is a progressive pathological change in the uterine lining, often associated with poor fertility and could lead to pyometra, a serious uterine infection【22†source】. CEH, along with the mammary mass, indicates a potential hormonal influence on these conditions. An intact female dog of her age may be at risk for hormonal imbalances leading to these issues.

2. Mammary Mass: The rapid growth and ulceration of the mammary mass are concerning for malignancy. As mentioned earlier, surgical removal is the primary treatment option for mammary tumors, and the type of surgery depends on various factors, including the extent of the mass and the dog's overall health【15†source】.

3. Arthritis: Addressing the dog's arthritis is also important, especially considering the stiffness in her gait. Management may include pain relief medication, joint supplements, and possibly modifications to exercise routines.

Given the complexity of her conditions, a comprehensive approach is needed. This should include:

• Diagnostic Imaging: To assess the extent of the mammary masses and check for possible metastases.
• Biopsies/Fine-Needle Aspirates: To determine the nature of the mammary masses and any other subcutaneous masses.
• Blood Work: To assess overall health status and organ function, especially considering her age.
• Discussion about Spaying: Given the history of CEH and mammary masses, spaying may be recommended to reduce hormonal influences that could be contributing to these conditions.

A multi-disciplinary approach involving a general veterinarian and possibly a veterinary oncologist and a surgeon may be needed to provide the best care for her. Prompt veterinary attention is crucial to address her health needs and to discuss the most appropriate treatment options.

Based on this patient's initial history, which aspects of a complete physical exam should be prioritized? (You may select more than one option.)

Based on the initial history of the 9-year-old intact female Australian shepherd with a mammary mass, arthritis, and cystic endometrial hyperplasia, several aspects of a complete physical examination should be prioritized:

1. Mammary Gland Examination: Given the presence of a mammary mass that has doubled in size and is ulcerated and bleeding, a thorough examination of all the mammary glands is crucial. This should include assessing the size, shape, consistency, and attachment to underlying tissues of the masses.

2. Abdominal Palpation: This is important to check for any abnormalities in the abdominal organs, which could be related to the cystic endometrial hyperplasia or potential metastases from the mammary tumor.

3. Lymph Node Examination: Palpating the regional lymph nodes, especially the axillary and inguinal nodes, is important to check for any signs of metastasis or systemic involvement.

4. Orthopedic Examination: Due to the reported stiffness in gait, a detailed orthopedic examination is necessary to assess the extent of arthritis and to determine any related pain or mobility issues.

5. Cardiovascular and Respiratory Assessment: Although not directly related to her current complaints, a routine evaluation of the heart and lungs is essential in older dogs, especially before considering any surgical intervention.

6. Neurological Examination: Although her neurological history is noncontributory, a basic neurological assessment should be part of a complete physical examination in a senior dog.

7. General Condition Assessment: Observing her overall condition, including hydration status, body condition, and coat quality, can provide additional insights into her general health.

Each of these aspects will provide vital information that can guide further diagnostic steps and treatment planning.

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Case Summary for Veterinary Consultation

Patient: 9-year-old intact female Australian Shepherd dog

Presenting Complaints:

• Mammary mass present for 8 months, recently doubled in size
• Ulcerated and bleeding mammary mass
• Dog licking the mass
• Stiffness in gait

Past Medical History:

• Arthritis
• Cystic endometrial hyperplasia
• No pregnancies in the past 5 years

Surgical History:

• None

Medications:

• Monthly prophylaxis for fleas and internal parasites

Allergies:

• No known drug allergies

Social History:

• Lives with one cat

Physical Examination Priorities:

1. Mammary gland examination: Assess all glands, focusing on the size, shape, and attachment of the mass.
2. Abdominal palpation: Check for abnormalities related to cystic endometrial hyperplasia or potential metastases.
3. Lymph node examination: Palpate regional lymph nodes for signs of metastasis.
4. Orthopedic examination: Evaluate extent of arthritis and mobility issues.
5. Cardiovascular and respiratory assessment: Essential before considering surgical options.
6. Neurological examination: Basic assessment as part of a complete physical exam.
7. General condition assessment: Observe hydration, body condition, and coat quality.

Recommendations:

• Immediate veterinary evaluation for comprehensive assessment of mammary masses and arthritis.
• Consider diagnostic imaging (e.g., thoracic radiographs) and fine-needle aspirate/biopsy of the mammary mass.
• Discuss surgical options for mammary masses, considering the dog's age and health status.
• Evaluate and address arthritis management.
• Discuss spaying considering the history of cystic endometrial hyperplasia and mammary masses.
• Further tests as deemed necessary by the veterinarian, including blood work and abdominal imaging.

This case should be approached with urgency due to the rapid growth of the mammary mass and the potential for malignancy, keeping in mind the overall health and quality of life of the dog.