Splenic Masses in Dogs

Splenic masses are a common finding in dogs. Studies show that about two-thirds are benign (e.g., hematoma, nodular hyperplasia, hemangioma), while about one-third are malignant, most commonly hemangiosarcoma (HSA).

Malignant Tumors

• Hemangiosarcoma (HSA): most common malignant splenic tumor. Highly vascular, often ruptures → hemoabdomen

  • Breed Predisposition: German Shepherds, Golden Retrievers, Labrador Retrievers, other large breeds

  • Prognosis: splenectomy alone: 1–3 months; splenectomy + adjuvant chemotherapy: 4–6 months

Benign Tumors

• Hemangioma: benign vascular tumor; excellent prognosis after splenectomy.

Non-Neoplastic Lesions

• Splenic Hematoma: common; may mimic malignancy when ruptured

• Nodular Hyperplasia: very common in older dogs; can cause splenomegaly or rupture

• Extramedullary Hematopoiesis (EMH): Proliferation of hematopoietic tissue in the spleen, often secondary to increased peripheral demand (e.g., chronic anemia); usually incidental but may appear as splenic nodules on imaging.

• Other causes: Abscesses, infarctions, or granulomatous disease occasionally present as splenic masses.

Diagnostics

• Imaging: ultrasound detects masses but cannot distinguish benign vs. malignant

• Staging: thoracic radiographs or CT recommended before surgery

• Bloodwork: CBC and coagulation profiles as indicated

• Histopathology: Required for definitive diagnosis

Ultrasound Features in Splenic Lesions

• Malignant Lesions (Hemangiosarcoma):

  • Appearance: Large, irregular, heterogeneous echotexture; mixed echogenicity (often hypoechoic areas from necrosis/hemorrhage).

  • Vascularization: Often highly vascular on Doppler; possible active bleeding.

  • Other findings: Peritoneal effusion common if ruptured; look for metastases in liver, omentum.

    
    

• Benign Tumors (e.g., Hemangioma):

  • Appearance: Well-defined, mixed echogenicity, may mimic HSA but less likely to rupture.

  • Vascularization: Can be vascular but usually less aggressive perfusion patterns than HSA.

  
  

• Non-neoplastic Lesions:

  • Hematoma: Variable echogenicity depending on clot age; often avascular on Doppler; may be well-encapsulated.

  • Nodular Hyperplasia: Small, round, well-circumscribed, sometimes hypoechoic nodules; usually incidental.

  • Extramedullary Hematopoiesis (EMH): Multiple small, hypoechoic nodules; often diffuse involvement.

  • Abscesses / Granulomas: Irregular, heterogeneous, may have gas or fluid pockets; avascular or minimal flow.

    
    

• Ultrasound can suggest malignancy (size, irregularity, vascularization, metastasis, effusion), but definitive diagnosis still requires histopathology.

Treatment

• Emergency Care: IV fluids, blood transfusions for hemoabdomen

• Splenectomy: Both diagnostic and therapeutic; pre-op counseling essential

• Adjuvant Chemotherapy: Recommended for HSA to extend survival time

  
  

Key Takeaway

Because two-thirds of splenic masses are benign but malignancy cannot be ruled out preoperatively, early detection, staging, and clear client communication are critical — especially for predisposed breeds.

Scan 1. B-mode imaging of splenic mass

Scan 2. Assessing Vascularization of the splenic mass with Power Doppler imaging