Humeral Aneurysmal Bone Cyst in a Cat with Sequential Computed Tomographic Findings

Area of Science:

• Veterinary Medicine
• Comparative Pathology
• Oncology

Background:

• Aneurysmal bone cysts (ABCs) are rare, benign, expansile bone lesions typically found in younger humans.
• While ABCs have been documented in various animal species, their occurrence in feline appendicular long bones is exceptionally uncommon.

Observation:

• A 7-year-old domestic shorthair cat presented with a progressively enlarging, painful mass on the right forelimb, causing lameness.
• Diagnostic imaging, including radiography and computed tomography (CT), revealed an expansile osteolytic lesion with associated vascular development in the proximal humerus.

Findings:

• Histopathological examination confirmed the diagnosis of an aneurysmal bone cyst.
• Despite surgical amputation of the affected limb and axillary lymph node, the cat succumbed to complications during the postoperative recovery period.

Implications:

• This case highlights the potential for aneurysmal bone cysts to occur in the feline humerus, presenting as aggressive bone lesions.
• Early recognition and aggressive surgical management are crucial for affected animals, though prognosis can be guarded due to potential complications.