Postoperative Computed Tomographic Assessment of the Complete Resection of an Infiltrative Lipoma Compressing the Spinal Cord in a Dog

SIMPLE SUMMARY: Infiltrative lipomas have a tendency to infiltrate adjacent muscle and fibrous tissue without metastasis, such as muscle; connective tissue; bone; and, in rare cases, peripheral nerves and the spinal cord. Incomplete surgical excision of infiltrative lipoma has been shown to increase recurrence. This case report describes a dog with an extensive infiltrative lipoma impinging on the vertebral canal, compressing the spinal cord and extending into the surrounding muscle layers and thoracic cavity. The mass was surgically removed, and subsequent postoperative computed tomography with the automated fat measurement technique confirmed complete removal. The patient’s prognosis could be assessed through postoperative computed tomography, and there has been no recurrence during the 2-year follow-up period. ABSTRACT: Infiltrative lipomas, which are locally invasive tumors composed of well-differentiated adipocytes, are histologically identical to lipomas but have a tendency to infiltrate adjacent muscle and fibrous tissue without metastasis, such as muscle; connective tissue; bone; and, in rare cases, peripheral nerves and the spinal cord. They differ from liposarcomas yet also exhibit neoplastic cell infiltration and often recur despite surgical removal. A 10-year-old spayed Maltese female dog presented with hindlimb paresis and back pain for two months. Computed tomography and magnetic resonance imaging revealed an extensive fatty mass impinging on the vertebral canal, compressing the spinal cord, and extending into the surrounding muscle layers and thoracic cavity. The mass was surgically removed, and subsequent postoperative computed tomography confirmed complete removal of the mass using Vitrea(®) advanced visualization fat measurement. Histopathological analysis confirmed that the mass was an infiltrative lipoma. The patient’s symptoms completely resolved after surgery, with no recurrence reported at the 2-year follow-up. This case highlights the benefits of using postoperative computed tomography combined with the automated fat measurement technique to determine whether reoperation is necessary or to predict patient prognosis by identifying potential residual lipoma post-surgery.