Mast Cell Tumours - a fickle beast

Tiny. Huge. Gone altogether. Back with a vengeance. How to tackle this worrying issue

French Bulldogs, like several other short-nosed breeds, are predisposed to developing mast cell tumours (MCTs) — a common type of skin cancer originating from mast cells within the immune system. These tumours can range from benign, slow-growing masses to aggressive, invasive lesions capable of metastasis. Due to their variable biological behaviour and tendency to recur, mast cell tumours require ongoing monitoring, prompt intervention, and long-term management under veterinary supervision.

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Early Detection and Diagnosis

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Routine skin checks are crucial for early detection, as mast cell tumours can mimic benign lumps such as lipomas or warts. Any new or changing mass should be evaluated promptly through fine needle aspiration (FNA) or biopsy for cytological or histopathological examination. Early-stage detection allows for more effective, minimally invasive treatment and significantly improves prognosis.

Veterinary cytology typically reveals mast cells containing characteristic purple-staining granules. Once diagnosed, staging is recommended to assess the extent of disease, often including blood work, lymph node aspiration, abdominal ultrasound, and thoracic radiographs. These tests help determine whether the tumour is localised or has metastasised.

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Conventional Surgical and Medical Management

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Surgical excision with wide margins (2–3 cm lateral and one fascial plane deep) remains the traditional treatment for localised mast cell tumours. However, achieving these margins can be difficult in areas with limited skin, such as the face or limbs — particularly relevant in compact breeds like the French Bulldog. Surgery also poses anaesthetic risks due to brachycephalic airway syndrome (BOAS) and related respiratory compromise. For this reason, alternative non-surgical approaches may be considered in suitable cases.

Following excision, the tumour is graded histologically (Grade I–III or low/high grade). Low-grade tumours often have an excellent prognosis with complete removal, while high-grade or recurrent tumours may require adjunctive therapies, such as radiation, chemotherapy (e.g., vinblastine, lomustine), or targeted therapy (e.g., toceranib phosphate / Palladia) to reduce recurrence risk.

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Stelfonta (Tigilanol Tiglate) Therapy

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For suitable mast cell tumours, Stelfonta (tigilanol tiglate) offers a non-surgical treatment option that avoids general anaesthesia and excision. Stelfonta is an intratumoural injectable medication that induces a localised inflammatory and necrotic response, destroying tumour cells and promoting wound healing through natural tissue regeneration.

The treatment is typically administered under mild sedation and local anaesthesia, making it particularly valuable for French Bulldogs, where general anaesthetic carries increased respiratory risk. Stelfonta is licensed for non-metastatic cutaneous or subcutaneous mast cell tumours that are accessible for intratumoural injection and confirmed by cytology or biopsy.

Treatment process:

• The tumour is measured, graded, and staged to ensure suitability.

• Prednisolone, diphenhydramine (or chlorphenamine), and omeprazole or famotidine are usually prescribed prior to and following treatment to stabilise mast cells and minimise systemic histamine release.

• The veterinarian injects Stelfonta directly into the tumour, followed by a controlled necrosis phase (typically over 3–7 days).

• The treated area may ulcerate and slough off, forming an open wound that heals naturally by secondary intention over several weeks.

Wound management involves gentle cleaning with saline or dilute chlorhexidine solution, avoidance of bandaging unless directed, and close monitoring for infection. Most lesions heal completely within 4–6 weeks, with minimal scarring.

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Effectiveness and Recurrence

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Clinical studies have shown Stelfonta achieves complete tumour resolution in approximately 75–80% of cases after one or two injections, depending on tumour size and grade. Recurrence rates are generally low when used appropriately, though new mast cell tumours may develop elsewhere on the body over time due to the breed’s genetic predisposition.

Recurrent or multiple tumours often require a multi-modal management plan, combining Stelfonta, surgical removal (if feasible), and systemic therapies such as tyrosine kinase inhibitors (TKIs) — e.g., toceranib phosphate (Palladia) or masitinib (Masivet) — which target cellular pathways involved in tumour growth.

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Potential Complications and Aftercare

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While Stelfonta avoids the inherent risks of general anaesthesia, it is not without side effects. Common short-term effects include:

• Localised pain, swelling, or inflammation around the injection site.

• Transient ulceration and discharge as necrosis occurs.

• Rarely, mild systemic reactions due to histamine release (vomiting, lethargy, or hives), managed with antihistamines and corticosteroids.

Severe complications are uncommon but may include delayed wound healing or local tissue overreaction. Appropriate pain management (e.g., NSAIDs) and protective collars are typically recommended to prevent self-trauma during healing.

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Ongoing Monitoring and Prevention

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Because French Bulldogs may develop additional mast cell tumours over time, lifelong vigilance is essential. Owners should perform weekly skin checks, palpating for new lumps, and report any changes immediately. Follow-up veterinary evaluations every 3–6 months are recommended for dogs with a history of mast cell tumours.

Supporting overall immune and skin health through a balanced diet rich in antioxidants and omega-3 fatty acids (e.g., Welactin or Grizzly Omega Health) may help reduce inflammation and support recovery. Weight management and stress reduction also benefit general wellbeing during and after treatment.

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Mast cell tumour management in French Bulldogs requires a strategic, multimodal approach tailored to tumour grade, recurrence, and the individual dog’s health status. Stelfonta injections provide an important alternative for suitable candidates, offering tumour control without the respiratory risks of anaesthesia. When used alongside systemic therapy, regular monitoring, and supportive care, most French Bulldogs achieve good quality of life and long-term disease control despite the breed’s predisposition to recurrence.

With careful case selection, appropriate adjunct therapy, and dedicated follow-up, modern treatment protocols enable effective, minimally invasive management of mast cell tumours while prioritising comfort and safety in brachycephalic patients.