Are Back Mice Real?

Non-specificity of the condition may lead to misdiagnosis

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Back mice is a colloquial term used to describe painful bumps in and around the hips, sacrum, and low back. It is not a medical term but one that people apply to many different conditions in which a fatty lump develops in or around the back and spine.

The term is used more by chiropractors than healthcare providers. Some argue that the non-specificity of the description may lead to misdiagnoses and incorrect treatment if the underlying causes are not properly investigated.

Potential causes of back mice.

Lara Antal / Verywell


Back mice were first described in medical literature 1937 when a healthcare provider named Emil Reis used the term in association with a condition called episacroiliac lipoma.

Since then, a number of other conditions have been associated with back mice, including Iliac crest pain syndrome, multifidus triangle syndrome, lumbar fascial fat herniation, and lumbosacral fat herniation.

Back mice is a term used to describe painful masses of fat which protrude (herniate) through the lumbodorsal fascia which covers the deep muscles of the low and middle back.


These fat masses tend to have a firm, rubbery quality to them. You might find them on the hip bones as well as the sacroiliac region. Back mice are movable beneath the skin and often found by chiropractors and massage therapist during a routine treatment.

Besides being unsightly, back mice can often cause excruciating pain, most often related to the underlying fascial damage and/or the pressure placed on nerve endings. They are typically tender to touch and can make sitting in a chair or lying on your back difficult.


Because of their nonspecificity, back mice are often diagnosed presumptively by injecting a local anesthetic into the lump. The belief is that, if the pain is relieved, then the lump is likely a back mouse. This is a problematic means of making a diagnosis since giving a local anesthetic, by its nature, will relieve nerve sensations and therefore pain.

An abnormal fatty growth should never be diagnosed by a chiropractor. Rather, it should be looked at by a qualified dermatologist or medical professional who can perform imaging studies and a biopsy if needed.

The fatty deposits can be any number of things, some serious and others not. The same applies to the nerve pain. While a lipoma is the most obvious explanation, others include:

  • Sebaceous cysts: A benign, fluid-filled capsule within the skin between the dermal and epidermal layers of skin
  • Subcutaneous abscess: The consolidation of pus beneath the skin which is often painful but not always red or inflamed in the early stages
  • Sciatica: Radiating nerve pain that runs down one or both legs caused by a herniated disc or a bone spur in the lower back
  • Liposarcoma: Malignant tumors that sometimes appear as fatty intramuscular growths

Painful lipomas are also associated with fibromyalgia, a condition that requires the care of a qualified rheumatologist.

lipomas on lower back
Lipomas on lower back.

DermNet / CC BY-NC-ND


Unless there is an unmanageable pain, a back mouse will not usually require treatment. This presumes, of course, that the growth is benign and has been properly diagnosed as such.

If surgery is indicated, it would consist of excision of the mice followed by repair of the fascia. This procedure appears to be the only way to achieve durable pain relief.

The problem is that some people have hundreds of back mice, making complete removal less likely. If the back mice are smaller, more extensive, and more fluid, liposuction may also be explored.

Complications of excisional surgery include scarring, bruising, uneven skin texture, and infection. Call your healthcare provider if you experience fever, chills, nausea, increasing pain, bleeding, or discharge following the procedure.

Complementary and Alternative Treatment (CAM)

Many chiropractors believe that back mice can be successfully treated by combining acupuncture and spinal manipulation. It is certainly a less invasive method of treatment and one that is unlikely to do any harm.

A 2016 case study published in Pain healthcare provider reported that the injection of a local anesthetic or steroids into the nodules, followed by dry needling (an alternative therapy similar to acupuncture), improved pain relief. The conclusions of the study are limited by the fact that only one subject was studied.

Frequently Asked Questions

  • What can healthcare providers do to get rid of back mice?

    There's no single treatment for back mice, as it's a catch-all term for any number of conditions associated with painful lumps on the back. That said, benign lumps that aren't causing pain or interfering with mobility can be left alone. Otherwise, injections of medication and/or steroids may be helpful.

  • When should a lipoma on the back be removed?

    Unless it's causing pain or making it difficult to move, there's no reason to remove a lipoma, as these growths are benign. If a back lipoma is bothersome, it can be excised (surgically removed).

  • What can cause fat herniation on the back?

    One cause, known as subfascial fat herniation, occurs when fat protrudes through a tear or hole in the fascia—the thin layer of connective tissue that encases muscles, organs, and other structures throughout the body—in the low back.

  • Can back lipomas feel squishy?

    Not usually. They tend to be feel firm and rubbery and can be moved beneath the skin when gently nudged.

  • What kind of healthcare provider should I see for an episacral lipoma?

    If you know for sure a lump on your back is an episacral lipoma, your general practitioner may send you to an orthopedist or orthopedic surgeon to determine if it should or can be treated and how best to do so. You also may get pain relief from a certified massage therapist who's familiar with the condition.

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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Ries E. Episacraliliac lipoma. Am J Obstet Gynecol 1937; 34:490-494.

  2. Bond WD. The problem with the back mouse. Associated Bodywork and Massage Professionals.

  3. Bicket MC, Simmons C, Zheng Y. The best-laid plans of "back mice" and men: A case report and literature review of episacroiliac lipoma. Pain Physician. 2016 Mar;19(3):181-8.

  4. Rosati E, Mariani D. The role of episacroiliac lipomas as a cause of pseudolumbago-sciatica syndromes. Arch Putti Chir Organi Mov. 1990.

  5. American Academy of Orthopedic Surgeons. Lipoma. Aug 2018.

  6. Tiegs-Heiden CA, Murthy NS, Glazebrook KN, et al. Subfascial fat herniation: sonographic features of back miceSkeletal Radiol. 2018;47(1):137-140. doi:10.1007/s00256-017-2772-9

  7. Erdem HR, Nacır B, Özeri Z, et al. Episakral lipoma: Bel ağrısının tedavi edilebilir bir nedeni [Episacral lipoma: a treatable cause of low back pain]Agri. 2013;25(2):83-86. doi:10.5505/agri.2013.63626

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