Spinal Epidural Lipomatosis

A 62-year-old man who was receiving long-term corticosteroid therapy for Wegener granulomatosis presented with progressive leg weakness over 1 week. He had the stigmata of Cushing syndrome: moon facies, truncal obesity, and a dorsocervical fat pad.

Sameh G. Aziz, MD, and Jon M. Sweet, MD, of Roanoke, Va, noted normal strength and sensation in all extremities but found bilateral ankle and patellar clonus. An MRI scan of the spine revealed marked deposition of epidural fat from T3 to T10, consistent with spinal epidural lipomatosis (SEL) (A, arrow). This finding was confirmed by fat-suppressed T2-weighted images (for instance, B, arrow).

SEL is an uncommon condition characterized by the abnormal deposition of unencapsulated, nonlocalized fat in the extradural space of the spinal canal; it is often associated with long-term corticosteroid treatment. The risk of SEL is directly correlated with the dose and duration of corticosteroid use. SEL occurs primarily in the thoracic region and on average involves 7 or 8 spinal cord segments, as in this case.

Because postoperative mortality approaches 20% in patients with SEL-who are often immunocompromised-surgical decompression is recommended only for those with spinal cord compression. Reduction in corticosteroid dosage, optimal use of corticosteroid-sparing agents, and physical therapy are the usual approaches in the absence of cord compression. This patient did well with these 3 maneuvers, including the up-titration of azathioprine.

Given the frequency with which corticosteroids are prescribed in primary care practice, it is important to be aware of SEL. Determining the cause of weakness can be a challenge in patients who take long-term or high-dose corticosteroids. When these patients have neurologic findings referable to spinal cord pathology, the threshold for ordering neuroimaging of the spine should be low. Early diagnosis and treatment of SEL can prevent a poor outcome.