As a chiropractor, you’ve likely encountered patients with persistent mechanical low back pain that defies conventional treatments. What if the root cause of this pain is a commonly overlooked condition known as back mice, or episacral lipomas? These small, tender nodules can significantly impact your patients’ well-being, yet many healthcare professionals are unaware of their presence and potential treatments.

The literature for episacral lipomas is relatively sparse, with few actionable themes. So, to help shed light on this clinical problem, we surveyed the ChiroUp provider network to collect their evidence-informed opinions about managing episacral lipomas.

In this blog, we’ll summarize our network’s input and dive into the top 7 things every chiropractor needs to know about back mice, from symptoms and diagnosis to effective treatment options that can boost your management and provide much-needed relief to your patients.

1. What is an Episacral Lipoma? Understanding the Basics

Episacral lipomas, often called "back mice" or "sacroiliac fatty nodules," can significantly contribute to low back pain. These small, tender subcutaneous nodules occur when the thoracodorsal fascia tears, causing a portion of the underlying dorsal fat pad to herniate through the tear, most commonly over the lumbosacral junction and posterior iliac crests. (1,2)

2. Who Gets Episacral Lipomas? Episacral Lipoma Risk Factors and Prevalence

Published research suggests episacral lipomas affect 10-16% of back pain patients. (3,4) Our survey of the ChiroUp provider network shows that episacral lipomas are estimated to affect about 28% of LBP patients. While individual survey estimates ranged between 1 and 100%, the vast majority of respondents reported figures falling within a range of 10 to 30%.

Although episacral lipomas can affect anyone, existing literature suggests that episacral lipomas might be more common in obese patients and females. (2,5)

3. Common Episacral Lipoma Locations: Where Do Episacral Lipomas Typically Appear?

Episacral lipomas, or back mice, are most commonly found in specific regions such as the sacroiliac, posterior superior iliac, and lumbar paraspinal areas. (5) These firm, rubbery, mobile nodules can be mistaken for other causes of low back pain but are distinguished by their characteristic locations and response to palpation. (6)

See this episacral lipoma location illustration:

4. Are Episacral Lipomas Painful? Exploring Episacral Lipoma Symptoms and Clinical Features

Episacral lipomas are often tender to touch, and pressing them can reproduce familiar pain patterns- ranging from a dull, achy soreness to sharp pain. Symptoms may include referred pain to the gluteal area, hip, thigh, or even the abdomen and groin. Symptoms may be exacerbated by trunk movements, such as transitioning from a bed or chair, and by weather changes. Symptoms may improve with light exercise, heat, or compression. (2)

Many researchers and clinicians believe that episacral lipomas become more or less tender in proportion to the irritability of the surrounding paraspinal tissues (i.e., if the surrounding muscle is irritated, the nodule tends to be more tender.) (2,7) Our 130 survey respondents largely concurred, but showed some variation in what they believe:

64% of our respondents believe episacral lipomas are “tender in direct proportion to surrounding tissue irritation.”
19 % feel they are “consistently tender regardless of surrounding tissue irritation.”
17% say episacral lipomas are “never tender.

Episacral lipomas could be an independent pain generator due to several potential mechanisms. The fatty tissue of these lipomas is innervated by nociceptive fibers, meaning that stimuli such as compression, torsion, edema, hemorrhage, or congestion within the lipomas could naturally provoke pain. (8,9) Additionally, lipomas that lie near the cluneal nerves can lead to direct compression and neuropathic pain. (8)

Deeper dive: See this prior top-rated chiropractic blog on Maigne Syndrome & Cluneal Neuropathy: The #1 Overlooked LBP Diagnosis.

5. Diagnosis of Episacral Lipomas: Clinical Features and Differential Diagnosis

Recognizing episacral lipomas is straightforward. The primary diagnostic criterion is the presence of a firm, tethered yet mobile fatty nodule over the lumbosacral or posterior iliac region. (2)

Episacral Lipoma Clinical Findings: (2,5,10)

Often escape palpation beneath the fingertips.
Highly mobile nodules may be more symptomatic.
Often oval-shaped, positioned transversely.
Typical sizes range from 1.3 to 10 centimeters.
Often a single nodule, but can appear in clusters.
Paraspinal hypertonicity is often present.

Clinicians should distinguish episacral lipomas from other conditions, such as myofascial trigger points, congenital cysts, ganglion cysts, heterotopic ossification, hemangiomas, angiolipoma, hematoma, lymph nodes, Dercum's disease (widespread painful lipomas), and malignant tumors. (2,8,11,12)

6. How Are Episacral Lipomas Managed? Effective Episacral Lipoma Treatments

Our survey identified utilization rates for several common episacral lipoma treatment strategies:

79% “Largely ignore them and just treat the accompanying diagnoses”

21% Recommend a “surgical consult (for persistently symptomatic lipomas)”

13% Apply “direct compression/ manual therapy to the lipoma”

11% Recommend “pain management consult/ injections”

9% Utilize “Heat or therapy modalities directed specifically at the lipoma”

6% Employ “Acupuncture or dry needling”

When asked about their top clinical pearls, the survey respondents shared several key themes and common practices. These insights offer valuable guidance for managing episacral lipomas effectively.

Address the Cause

Most manual therapists argue that addressing any underlying lumbosacral biomechanical dysfunction can alleviate generalized edema and stress in the area, thereby reducing the tenderness and relevance of episacral lipomas.

Patient Education

Several practitioners appreciated that episacral lipomas may become more noticeable during acute LBP flare-ups, prompting unnecessary concern. A significant number of practitioners emphasize the importance of educating patients about the benign nature of these fatty deposits. Clinicians highlighted the need to reassure patients that episacral lipomas are usually incidental findings, unrelated to their acute pain episodes, and typically do not require aggressive treatment. In such cases, they advise patients to monitor the lipomas for changes in size, tenderness, or mobility but generally discourage active intervention unless these symptoms persist.

Additional home advice included recommending creams, heat, or warm baths for relief and promoting an anti-inflammatory diet.

Bonus: ChiroUp subscribers can download and share the latest patient education infographic, Understanding Episacral Liopomas, by visiting their Forms Library and searching “Lipoma”.

Manual Therapies

While a minority of DCs (13%) employ direct compression to the lipoma, many chiropractors felt that heavy manual therapies like direct myofascial release or deep massage could potentially exacerbate symptoms, making adjuncts like ice, modalities, laser, or dry needling preferable options. Likewise, several clinicians relayed the importance of counseling patients to avoid aggressive self-massage, compressive clothing, and gear like police or construction duty belts that could aggravate sensitized tissue. Direct needling has some literature support. (6)

Surgical or Medical Consult

A common recommendation was to consider referring patients for surgical consultation if the lipomas significantly interfere with daily activities or do not respond to conservative management. However, the decision to pursue surgical intervention appears to be tempered by the fact that some surgeons are unaware of an episacral lipoma’s relevance or decline to operate on these benign growths.

Some survey respondents (11%) believe that pain management anesthetic or steroid injections are appropriate for treating episacral lipomas, a view supported by limited research. (1) Additionally, a few providers recommended ozone injections as a viable treatment option, indicating that alternative approaches may also offer benefits.

7. Managing Episacral Lipomas: Tips for Chiropractors and Patients

Overall, the collective input from chiropractors indicates a conservative approach to managing episacral lipomas, prioritizing patient education and symptomatic relief while reserving more invasive treatments for cases where conservative measures prove insufficient.

Episacral lipomas, or back mice, may be small in size, but they can profoundly impact your patients’ quality of life. Chiropractors can play a crucial role in diagnosing and treating episacral lipomas. Understanding their symptoms, recognizing their clinical features, and knowing the most effective treatment options can significantly enhance your diagnostic and therapeutic toolkit.

Staying sharp and up-to-date with the latest research is key to providing the best patient care. The insights in this blog come directly from the collective expertise of the ChiroUp network.

By joining ChiroUp, you'll gain access to the latest evidence-based protocols, empowering you to deliver better outcomes with confidence. Plus, you'll become part of a community that’s not just keeping pace with the future of chiropractic care—it's leading it.

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1. Erdem HR, Nacir B, Ozeri Z, Karagoz A. Episacral lipoma: a treatable cause of low back pain/Episakral lipoma: bel agrisinin tedavi edilebilir bir nedeni. Agri: The Journal of The Turkish Society of Algology. 2013 Apr 1;25(2):83-7.
2. Cañis Parera M, Expósito Izquierdo M, Cabré Vila JJ. Historical Review of Studies on Sacroiliac Fatty Nodules (Recently Termed “Back Mice”) as a Potential Cause of Low Back Pain. Pain and Therapy. 2021 Dec;10(2):1029-50. Link
3. Copeman WS. Fibro-fatty Tissue and its Relation to “Rheumatic” Syndromes. British Medical Journal. 1949 Jul 7;2(4620):191. Link
4. Singewald ML. Another Cause Of Low Back Pain: Lipomata In The Sacroiliac Region.
5. Rovaris MF, Prall JM. Episacroiliac Lipomas: A Possible Undetected Cause of Non-specific Low Back Pain. Physical Therapy Rehabilitation Science. 2023 Dec 30;12(4):413-8. Link
6. 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;19(3):181. Link
7. Copeman WS. A clinical contribution to the study of the aetiology of the fibrositic nodule. Annals of the Rheumatic Diseases. 1943 Dec;3(4):222. Link
8. Lee SW, Van Dien C, Won SJ. Adipose tissue as pain generator in the lower back and lower extremity: application in musculoskeletal medicine. HCA Healthcare Journal of Medicine. 2020;1(5):257. Link
9. Singh A, Ramalingam K, Kai LK, Jeremy SV. Episacral Lipomata as a Cause of Lower Back Pain: Series of Cases Managed by Excision. Global Spine Journal. 2016 Apr;6(1_suppl):s-0036. Link
10. Tiegs-Heiden CA, Murthy NS, Glazebrook KN, Skinner JA. Subfascial fat herniation: sonographic features of back mice. Skeletal Radiology. 2018 Jan;47:137-40. Link
11. McTighe S, Chernev I. Intramuscular lipoma: a review of the literature. Orthopedic reviews. 2014 Oct 10;6(4). Link
12. Kuwano Y, Ishizaki K, Watanabe R, Nanko H. Efficacy of diagnostic ultrasonography of lipomas, epidermal cysts, and ganglions. Archives of dermatology. 2009 Jul 1;145(7):761-4. Link

Top 7 Things Chiropractors Need to Know About Back Mice (Episacral Lipomas)