Objective: To report arthroscopic diagnosis and treatment of synovial hemangioma in a dog.
Study design: Case report.
Animal: Standard Poodle (8-year-old neutered male).
Methods: A soft tissue density mass observed radiographically in the left stifle joint of a dog with a 2-month history of recurrent lameness, hemarthrosis, and a slight cranial drawer sign, was located by diagnostic arthroscopy and surgically excised via arthrotomy.
Results: Histologic evaluation revealed tissue composed of variably sized cavernous vascular spaces filled with erythrocytes that were considered compatible with synovial hemangioma.
Conclusions: In this dog, synovial hemangioma evident as a soft tissue mass on radiographs was associated with chronic lameness and hemarthrosis, and resolved with surgical excision.
Clinical relevance: Synovial hemangioma, although seemingly rare in dogs, should be considered in the differential diagnosis for nontraumatic, recurrent lameness, and unresponsive to anti-inflammatory therapy when there is a circumscribed intracapsular soft tissue mass evident radiographically together with hemarthrosis.