Non-dysraphic Thoracic Spinal Lipoma in an Obese Adult Woman: A Case Report

Spinal lipoma is a rare benign tumor characterized by abnormal proliferation of mature adipose tissue within the spinal canal. The non-dysraphic type typically occurs in adults without vertebral anomalies and is extremely rare at the thoracic level. We report a case that developed in the setting of severe obesity, suggesting a possible link between obesity and tumor progression. A 51-year-old woman (152.2 cm, 81.3 kg, BMI 35.1) with a history of diabetes and prior lumbar disc surgery resulting in cauda equina injury presented with progressive right-dominant periumbilical dysesthesia for two years. Neurological examination revealed right-sided hypoalgesia at the Th7-L1 dermatomes. Thoracic MRI revealed a well-demarcated intradural extramedullary mass on the right side at the Th8-9 level, showing hyperintensity on both T1- and T2-weighted images and hypointensity on fat-suppressed sequences, consistent with a spinal lipoma. CT demonstrated no bony abnormalities or evidence of spinal dysraphism. Under general anesthesia, a wide laminectomy at Th7-8 and dome laminectomies at Th6 and Th9 were performed. A yellowish, soft fatty mass was found firmly adherent to the spinal nerve roots. A partial resection was performed for decompression, leaving a small portion of fatty tissue caudally. Histopathological examination confirmed lipoma. Postoperatively, the patient's truncal dysesthesia entirely resolved with no new neurological deficits; bladder and rectal dysfunction remained unchanged. No recurrence was observed on MRI during the one-year follow-up. This rare case of non-dysraphic thoracic spinal lipoma occurred in the setting of severe obesity. Obesity and weight fluctuations may have contributed to tumor growth and symptom progression; partial decompression with long-term MRI follow-up is recommended.