Spinal Lipoma
A benign fatty growth involving the spinal cord
Quick Facts
- Type: Spinal cord developmental condition
- Nature: Benign (non-cancerous) fatty mass
- Key concern: Tethering of the spinal cord
- Main treatment: Surgery in selected cases
Overview
A spinal lipoma is a benign (non-cancerous) collection of fatty tissue located in or next to the spinal cord. Most spinal lipomas are present from birth and form as part of abnormal development of the lower spine, placing them among the closed (skin-covered) spinal conditions sometimes grouped with neural tube developmental problems.
The main concern with a spinal lipoma is not that it spreads, because it does not, but that it can be attached to the spinal cord. This attachment can tether the cord, holding it lower in the spinal canal than normal and stretching it as a child grows. Tethering can gradually affect nerves that control the legs, bladder, and bowel. Some spinal lipomas cause no problems, while others need surgery to prevent or relieve symptoms.
Symptoms
Many spinal lipomas are first noticed because of a sign on the lower back or because of symptoms from a tethered spinal cord:
- A fatty lump, dimple, skin tag, or patch of hair over the lower back
- Leg weakness, numbness, or differences in size between the legs
- Changes in walking, foot shape, or balance
- Bladder problems, such as wetting, urgency, or incomplete emptying
- Bowel problems, such as constipation or incontinence
- Back or leg pain, especially in older children and adults
Symptoms may appear or worsen during growth spurts, which is why follow-up is important.
Causes
Spinal lipomas develop because of abnormal formation of the lower spinal cord and overlying tissues early in pregnancy. During development, fatty tissue becomes incorporated into or attached to the spinal cord where it should not be. The reasons are not fully understood and are thought to involve a mix of developmental and possibly genetic factors. Unlike open neural tube defects, the skin over a spinal lipoma is usually intact, which is why these are called closed spinal conditions.
Risk Factors
- Present from birth, so risk relates to early development rather than later lifestyle
- Sometimes associated with other spinal cord differences
- A visible skin marker over the lower back can be an early clue
- Growth in childhood can unmask symptoms in a previously silent lipoma
Diagnosis
A spinal lipoma is diagnosed using imaging, often prompted by a skin sign or by symptoms:
- MRI of the spine: The key test, clearly showing the fatty mass, its relationship to the spinal cord, and whether the cord is tethered.
- Ultrasound: Useful in young infants whose spine has not fully hardened.
- Examination: Checking the back for skin markers and assessing leg, bladder, and bowel function.
- Bladder testing (urodynamics): To evaluate how the bladder is working.
Treatment
Treatment is individualized and depends on whether the lipoma is causing or is likely to cause problems.
- Monitoring: Some lipomas, especially those without symptoms, are followed closely with examinations and imaging.
- Surgery: An operation may be done to remove or reduce the fatty mass and release a tethered cord, aiming to prevent worsening of nerve function. The decision weighs the benefits against the risks of surgery.
- Supportive care: Physical therapy, bladder and bowel management, and orthopedic care help with any nerve-related effects.
- Ongoing follow-up: Regular review is important, particularly during periods of growth.
Prevention
Spinal lipomas form before birth and cannot be reliably prevented. The focus is on early recognition and protecting nerve function:
- Have any skin marker over the lower back of an infant evaluated by a doctor
- Attend recommended follow-up so problems are caught early
- Report new leg, bladder, or bowel symptoms promptly
- Maintain general prenatal health, including adequate folic acid, which supports healthy spinal development
When to See a Doctor
See a doctor if you or your child has a fatty lump, dimple, hair patch, or unusual mark over the lower back, or if there are signs of a tethered cord, such as:
- New or worsening leg weakness, numbness, or changes in walking
- New bladder problems, such as wetting, urgency, or retention
- New bowel problems, such as constipation or incontinence
- Back or leg pain, or changes in foot shape
Prompt evaluation can help protect nerve function before damage becomes permanent.
Frequently Asked Questions
Is a spinal lipoma cancerous?
No. A spinal lipoma is a benign, non-cancerous mass of fatty tissue. It does not spread to other parts of the body. The main concern is that it can attach to and tether the spinal cord, which may affect nerve function over time.
What problems can a spinal lipoma cause?
If it tethers the spinal cord, it can cause leg weakness or numbness, changes in walking or foot shape, and bladder and bowel problems. Some people have a fatty lump or skin mark on the lower back but no symptoms at all.
How is a spinal lipoma diagnosed?
An MRI of the spine is the main test, showing the fatty mass and whether the spinal cord is tethered. In young infants, ultrasound may be used. A doctor will also examine the back and assess leg, bladder, and bowel function.
Does a spinal lipoma always need surgery?
No. Some are monitored without surgery, especially when they cause no symptoms. Surgery to remove the lipoma and release a tethered cord may be recommended to prevent or relieve nerve problems, weighing the benefits against the risks.
When should a skin mark on a baby's back be checked?
Any fatty lump, deep dimple, hair patch, or unusual mark over the lower back should be evaluated, because it can point to an underlying spinal lipoma or tethered cord. Early evaluation helps protect nerve function.
References
- National Institute of Neurological Disorders and Stroke (NINDS). Tethered Spinal Cord Syndrome.
- MedlinePlus, U.S. National Library of Medicine. Spinal cord conditions.
- American Association of Neurological Surgeons (AANS). Spinal cord abnormalities.
- Spina Bifida Association. Tethered spinal cord.