Computed tomographic findings, surgical management and postoperative outcomes of large intermuscular lipomas in the hindlimb of 11 dogs

Abstract

Objective: Lipomas are benign adipose tissue tumours of mesenchymal origin and can originate in various locations. Intermuscular lipomas in the thigh can cause substantial hindlimb expansion in the dog. We describe the computed tomography findings, surgical management and the outcomes of 11 dogs with large intermuscular lipomas of the hindlimb. Design: Retrospective case series. Methods: Medical records between 2009 and 2019 of dogs presenting to The Animal Hospital at Murdoch University were reviewed. Inclusion criteria included dogs with a histologically confirmed, large hindlimb lipoma that was surgically excised following preoperative computed tomography (CT) imaging. Results: CT with intravenous contrast revealed a well-defined, smoothly marginated, fat attenuating mass with minimal vascularity, separating the muscle bellies of the caudal hindlimb. The mass was often in close proximity to the femoral artery and vein. All lipomas were marginally excised. At surgery, some lipomas were intimately associated with the sciatic nerve and some showed infiltration of, or attachment to, neighbouring muscle that could be excised en bloc with the lipoma. Postoperative closed-suction wound drainage was used in 6 of 11 dogs. One dog required revision surgery due to partial wound dehiscence. Long-term follow-up with owners reported good postoperative function of the affected hindlimb in all dogs. One dog developed an infiltrative lipoma in the same location 22 months post-excision. Conclusion: Preoperative CT allowed a presumptive diagnosis of intermuscular lipoma and facilitated surgical planning for marginal excision. Large intermuscular lipomas of the hindlimb can be safely excised with minimal short-term complications, good long-term functional outcome and low likelihood of recurrence.