33rd Annual Scientific Meeting proceedings

Introduction

Hemangiosarcoma is a rarely reported condition in equids. Previously documented cases are scarce, especially regarding synovial structures. Vague clinical symptoms often make an antemortem diagnosis difficult. This case report describes the clinical presentation and antemortem diagnostic procedures of an adult warmblood horse with a confirmed hemangiosarcoma in the digital flexor tendon sheath (DFTS).

 

Case description

A 14-year-old warmblood gelding was admitted with a 3-week history of diffuse swelling of the right hind distal limb, non-responsive to conservative treatment. Ultrasonographic and magnetic resonance examination revealed a severe, proliferative tenosynovitis of the DFTS. Tenoscopy confirmed a hemorrhagic tenosynovitis without primary tendinous lesion.

Evolution was initially favorable, however diffuse swelling persisted. Two weeks post-surgery, the horse was acutely lame with hemorrhage from the proximal portal. Ultrasonographic examination was suggestive for intrathecal bleeding with signs of vasculitis. D-dimers were elevated, prothrombin time was normal. Intra-arterial contrast enhanced computed tomography revealed a suspected deep vein thrombosis syndrome of the main vasculature of the distal limb with marked diffuse synovial contrast enhancement in the DFTS. Synovial biopsies were taken during a tenoscopic intervention.

Results

Histopathologic examination revealed the presence of a highly malignant hemangiosarcoma with positive immunohistochemical stain (VWF). The horse was euthanized.

Conclusion

Persistent, proliferative tenosynovitis, with diffuse limb swelling, unaccountable hemorrhage, signs of vasculitis and thrombosis can be suggestive of synovial hemangiosarcoma.