Epidural Lipomatosis

The commonest cause is long-term exposure to steroids — either steroid medication taken for another condition, or, less often, the body's own overproduction of steroid hormone (as in Cushing's syndrome). Obesity is the next most frequent association, and the condition is increasingly viewed as part of the picture of metabolic syndrome. In a proportion of people no clear cause is found. In each case, the underlying tendency is towards laying down more fat in the epidural space than normal.

Many people with epidural lipomatosis have no symptoms at all, and it is discovered incidentally on a scan performed for another reason. When symptoms do occur, they arise from crowding of the spinal canal and can include back pain, pain, numbness or tingling in the legs, and heaviness or aching in the legs on walking that eases with rest or bending forward — a pattern similar to spinal narrowing from other causes. In severe cases there can be more significant weakness or, rarely, disturbance of bladder or bowel function.

As with other causes of pressure in the spinal canal, certain features need prompt assessment: new or worsening leg weakness, numbness spreading to the saddle area, or any disturbance of bladder or bowel control. Progressive difficulty walking also warrants review. These are uncommon in epidural lipomatosis but are important to recognise because they may indicate significant compression.

MRI is the key test and is considered the gold standard, clearly showing the excess fat in the epidural space and how much it is crowding the spinal cord or nerves; it also allows the severity to be graded. Because the condition is often found incidentally, an important part of the assessment is judging whether the fat build-up actually explains a person's symptoms, or whether another cause is responsible. Where steroids or a hormonal condition are suspected, relevant tests and a medication review are arranged.

For most people, treatment is directed at the underlying cause rather than at the fat directly. Where steroids are responsible and can be safely reduced or stopped, this is done carefully in conjunction with the doctor managing the original condition, and can lead to improvement. Where obesity is the driver, weight loss is the mainstay and can meaningfully reduce the fat and relieve symptoms. Any hormonal condition, such as Cushing's syndrome, is treated in its own right. Symptomatic measures such as physiotherapy and pain relief support recovery.

Surgery is reserved for people with severe symptoms — significant nerve compression causing weakness or major walking difficulty — that do not respond to treating the underlying cause, or where the cause cannot be modified. The operation, a decompression, removes bone as needed and the excess epidural fat to relieve the pressure on the nerves. As with any spinal surgery it carries risks, and the decision is made individually, weighing the severity of symptoms against those risks.

The outlook is generally favourable, particularly where a modifiable cause such as steroid use or excess weight can be addressed, which can improve both the imaging appearance and the symptoms. Mild, incidental cases often need no treatment at all beyond attention to general health. Where surgery is required for severe compression, it can relieve symptoms, though recovery depends on how long and how severely the nerves were compressed beforehand.

Myth: "Epidural lipomatosis is a tumour." Fact: It is an overgrowth of ordinary fat, not a tumour and not cancer.

Myth: "It always causes symptoms." Fact: It is frequently found by chance on scans and causes no symptoms in many people.

Myth: "It always needs surgery." Fact: Most people are managed by addressing the cause; surgery is reserved for severe, unresponsive cases.

This page is for general education and does not replace an individual assessment. Treatment depends on a person's specific symptoms, examination findings, imaging findings and overall health, and should always be discussed with a suitably qualified healthcare professional.

Inside the bony spinal canal, surrounding the protective sac that contains the spinal cord and nerves, there is normally a small amount of fat. Spinal epidural lipomatosis is a condition in which this fat becomes excessive, building up until it crowds the canal and can press on the nerves. It is not a tumour and not cancerous — it is an overgrowth of ordinary fat. It is most commonly associated with prolonged use of steroid medication and with obesity, and is increasingly recognised on MRI scans. Often it causes no symptoms and is found by chance, but when the build-up is severe it can produce back pain, leg symptoms and difficulty walking. This page explains what causes epidural lipomatosis, how it is diagnosed, and how it is managed.

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• —Guideline note (place near references): No dedicated NICE or AAOS clinical practice guideline specific to spinal epidural lipomatosis was identified at the time of writing; management follows peer-reviewed evidence and specialist consensus.

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.