Splenic Cancers In Dogs And Cats

Cancers of the spleen are relatively common in dogs and less frequent in cats, but when they occur, they are often severe and life-threatening. In dogs, the most common malignant splenic tumour is hemangiosarcoma, an aggressive cancer of blood vessel origin that frequently metastasises to the liver, lungs, and heart. Other splenic tumours include lymphoma, histiocytic sarcoma, and hemangioma, a benign but often indistinguishable counterpart to hemangiosarcoma. In cats, splenic lymphoma and mast cell tumours are the most frequent.

Splenic cancers are notorious for being silent until they rupture or bleed, often presenting as an emergency. Because clinical signs are vague, accurate imaging and staging are critical for immediate decision-making and long-term treatment planning.

Splenic tumours may cause:

• Sudden weakness or collapse due to internal bleeding.
• Pale gums, lethargy, or rapid breathing.
• Abdominal swelling or discomfort.
• Chronic weight loss, poor appetite, or intermittent lethargy.

Diagnosis often begins with abdominal ultrasound or radiographs, which may show an enlarged spleen or masses. Fine needle aspirates or biopsy may be attempted, though cytology yields limited information in hemangiosarcoma cases. CT scans are increasingly used for staging but may miss microscopic or early metastases. PET-CT adds a new level of clarity by showing functional cancer activity rather than just structure.

Because splenic tumours are often aggressive and systemic, PET-CT provides vets with essential insights beyond conventional imaging.

The primary benefits of PET-CT  include:

• Whole-body staging. Detects metastases in the liver, lungs, heart, lymph nodes, and other organs commonly affected by hemangiosarcoma.
• Differentiation of benign vs. malignant disease. Helps distinguish metabolically active malignant tumours from benign splenic nodules or hyperplasia.
• Surgical planning. Confirms whether splenectomy (spleen removal) is appropriate by identifying hidden spread that may alter treatment recommendations.
• Radiation and chemotherapy guidance. PET-CT identifies disease extent and monitors metabolic response to systemic therapies.
• Prognostic clarity. Uptake intensity and distribution can help guide realistic discussions about expected outcomes and survival times.

Splenic cancers often present owners and veterinarians with urgent, high-stakes decisions. The uncertainty surrounding whether a mass is benign, malignant, or metastatic can create significant anxiety. PET Theranostics helps reduce this uncertainty by providing accurate whole-body imaging, giving vets confidence in staging, surgical planning, and therapy selection.

By integrating PET-CT into managing splenic tumours, veterinary teams can identify metastasis earlier and offer owners the most precise possible understanding of their pet’s condition. Referrals are now available. Contact our team for any questions.