Tumors & Cancers in Guinea Pigs: Vet Guide 2025 🎗️🐹

— Written by Dr Duncan Houston BVSc, founder of Ask A Vet —

1. Introduction

Though relatively uncommon in young piggies, tumors become more common with age—up to 30% of guinea pigs over 3 yrs may develop growths ([turn0search0])

2. Types of Tumors & Where They Occur

• Skin tumors: ~15% of tumors, often benign trichofolliculomas—firm, slow‑growing nodules on rump, skin, or ear, occasionally ulcerated ([turn0search0])
• Mammary tumors: Glandular swellings—fibroadenomas common; up to 75% may be malignant fibro‑adenocarcinomas needing careful evaluation ([turn0search0])
• Reproductive tumors: Uterine leiomyomas and ovarian teratomas common in unspayed sows ([turn0search0])
• Lung tumors: Benign bronchogenic adenomas (~30–35% of tumors)—may mimic pneumonia ([turn0search0])
• Lymphoid tumors: Lymphocytic leukemia or T‑cell lymphoma—often fatal in weeks ([turn0search0])
• Other rare sites: Liver, bladder, bone, adrenal, intestinal tumors reported but less common ([turn0search0])

3. Recognizing the Signs

• Visible lumps—firm, round, or ulcerated bumps under the skin
• Swelling of mammary areas with clear or bloody fluid
• Abdominal distension, vaginal bleeding in reproductive cancers
• Respiratory signs—coughing, sneezing, lethargy—if lung tumors present
• Lymph node enlargement, poor coat, weight loss, decreased appetite

4. Diagnosing Tumors

• Physical exam: Palpate lumps and evaluate overall health
• Fine needle aspiration or biopsy: Cytology distinguishes benign vs malignant lesions
• Imaging: X‑ray, ultrasound, CT scans to assess internal spread or lung masses
• Bloodwork: CBC/chemistry to detect systemic involvement
• Lymph node sampling: If lymphoma is suspected

5. Treatment Options

Surgical Removal

• Primary choice for skin, mammary, reproductive tumors—complete excision possible
• Uterine or ovarian tumors: spay often resolves issue ([turn0search1])

Systemic Therapy

• Radiation and chemotherapy may be considered for malignant types, though less common in practice
• Palliative care with supportive nutrition and pain control

Treatment by Tumor Type

• Skin/mammary: Surgery → good prognosis if complete excision
• Reproductive: Spay resolves benign growths; recurrence rare
• Lung: Surgical or medical management for symptoms; often managed as chronic disease
• Lymphoid cancers: Prognosis poor—survival lasts 2–3 weeks after onset ([turn0search0])

6. Post‑Op & Long‑Term Management

• Follow-up exams every 2–4 weeks initially
• Manage post‑op pain and wound care closely
• Monitor for recurrence or metastasis, especially in malignant cases
• Quality of life monitoring—comfort, pain, mobility, appetite

7. Prognosis by Tumor Type

8. Prevention & Early Detection

• Spay females early to prevent reproductive tumors ([turn0search1])
• Conduct monthly checks for new lumps or changes
• Prompt vet evaluation of any new mass or unusual behavior
• Maintain clean, low‑stress environment and balanced diet
• Annual veterinary wellness exams for aging piggies

9. Role of Ask A Vet

• 📸 Remote assessment: review photos of lumps, swelling
• 📅 Guide on when surgery vs monitoring is warranted
• 💊 Post‑op care: wound guidance, meds, pain control
• 🔔 Recurrence alerts: help schedule follow‑ups
• 🧭 Referral referrals: connect with exotic pet specialists

10. Conclusion

Tumors can be benign or malignant—and early diagnosis and treatment greatly improve outcomes. Skin and reproductive growths often have a good prognosis with surgery or spay. Lung and lymphoid tumors require careful management, and lymphoma sadly has a poor outlook. With attentive monitoring, thoughtful veterinary care, and Ask A Vet support, guinea pigs with tumors can often live comfortably and enjoy quality of life. 🐾

Noticed a lump on your guinea pig? Get veterinary evaluation promptly and use the Ask A Vet app to guide treatment, surgery planning, recovery, and long-term monitoring. 📱

— Dr Duncan Houston BVSc, Ask A Vet