Synovial myxoma with cyst formation in the hip joint of a central bearded dragon.

Abstract

Degenerative bone lesions are rarely described in reptiles and belong mainly to the broad spectrum of metabolic bone diseases. Here we describe a 7-y-old female central bearded dragon (Pogona vitticeps) with a complex unilateral neoplastic lesion in the hip joint. The animal was presented because of severe progressive swelling of the left hindlimb, apathy, and weight loss. The swelling was soft and surrounded the left femur. Full-body radiographs were performed in 2 orthogonal projections. The main radiologic findings were severe soft tissue swelling centered on the proximal third of the left femur and an absent left femoral head. The caretaker elected euthanasia, and a postmortem examination was performed, followed by subsequent histologic examination. The swelling consisted of variably sized myxomatous proliferations and cysts that invaded the femoral bone. Furthermore, several long bones had lesions consistent with metabolic bone and degenerative joint diseases. Synovial myxomas are rare lesions of the joints that have, to our knowledge, not been described previously in reptiles.