INFORMATION
An Overlooked Cause of Back Pain: Episacral Lipoma
Episacral lipoma is a treatable but frequently missed cause of low back pain.
Updated: · General information
What is an episacral lipoma?
Episacral lipomas are deep-seated, rubbery and often mobile fatty nodules, usually located over the upper part of the buttocks. They consist of herniated fatty tissue arising from an inherited weakness, or a tear caused by trauma, in the connective tissue covering the back and lumbar muscles. They are usually painless, and when painless they require no treatment.
When do they cause pain?
This herniated fatty tissue may occasionally become entrapped and inflamed, or may compress the surrounding sensory nerves, making it a significant cause of both acute and chronic low back pain. Patients typically present with back pain that is more pronounced on one side and may radiate into the buttock and leg; careful physical examination can reveal small, tender nodules in the sacroiliac region.
Why does it matter?
Without careful physical examination, an episacral lipoma is frequently missed, and in people who also have a mild disc herniation it can markedly increase the pain and lead to unnecessary treatment. It should therefore be considered in the differential diagnosis of low back pain. Alongside physical therapy, a physician may consider injection into the nodule where this is judged necessary.
