Intramuscular Hemophilic Pseudotumor in a Dog: Imaging Findings and Surgical Treatment.

An 8-month-old male, entire Cocker Spaniel dog was referred for investigation of severe right pelvic limb lameness. Previous history included a diagnosis of hemophilia A. On CT, a large, heterogeneous, rim-enhancing soft tissue mass was affecting the right thigh. Given the severe lameness and pain, surgical resection was performed. The dog recovered uneventfully, returning to full limb function within 8 weeks. A chronic organized hematoma was confirmed histologically, resembling a hemophilic pseudotumor described in humans. This case describes the imaging findings, treatment, and outcome of an atypical presentation of a muscular hemophilic pseudotumor in a dog.