1952 Sicard – Lipomes épisacro-iliaques

This is a two-page article from 1952 written in French about lipomes épisacro-iliaques et lombo-sciatiques (also known as back mice).

It was published in the magazine “Le Presse Medicale” and signed by André Sicard and G. Lord.

lipomes épisacro-iliaques

The main author is André Octave Adrien Sicard (1904-2002). He was a surgeon in Paris and the president of the French “Académie de médicine”.

In their conclusions they stated that the lipomes épisacro-iliaques are a FREQUENT and COMMON observation, and in some cases can be responsible for causing lumbosacralgia and lumbosciatalgia BUT it is still DIFFICULT to assert the relationship between the fatty nodule and the pain syndrome. The awakening of the pain by the pressure of the lipomas is, according to them, the best suspicious sign.

From the 12 operated cases they got 7 cures. The other patients underwent certain degrees of relief.

There are still many questions to answer, especially about the etiopathogenic factors, the failure in certain operated patients, and the histological findings.

Sicard makes the same questions that we do:

“Pourquoi parmi ces lipomes développés dans la meme région? Se présentant avec les mémes caractères, les uns sont ils silencieux, les autres associés à des douleurs souvent très pénibles?“

[Why do these lipomes épisacro-iliaques develop in the same region? Presenting in similar ways, some are silent and others very painful]

He further questions himself: What is the relationship between the lipoma and the pain? Are the lipomes épisacro-iliaques the cause or the consequence of this syndrome?

Notes on the article:

Lipomes épisacro-iliaques et lombo-sciatiques

Par MM. André Sicard et G. Lord


Sicard presented 12 cases and commented about previous works from authors such as Hittner, Copeman or Florentin Louyot.

They presented 12 observations about a SMALL GREASY NODULE covering the posterior part of the sacroiliac joint.

In 1888, Dercum described a painful adiposis, but he didn‘t underline the peculiar character of the Lipomes épisacro-iliaques, but later other authors such as Mathieu, Bucquoy and Darti Gnolles brought observations of lipomas associated with lumbosciatic patients, especially intraspinal lipomas.

In 1987 E. Ries brought the first observation of painful sacroiliac lipomas or lipomaes épisacro-iliaques to the Chicago Gynecology Society.

Anglo-Saxon writers quickly became interested in the question. James Hoffmann and MacDermot published about it.

But it was Copeman and Hittner who presented the anatomical pathological support about this “new entity”.

Sicard and Lord also mentioned the work of Joseph Rochegude and Florentin and Louyot.

The lipomes épisacro-ilaques are observed with greater frequency in women. Ries found that from the 317 cases 271 were woman. Hittner, 36 from 50.

Sicard ONLY presented observations about women.

Ages vary from 38 to 54 (average 45). It seems that the lipomes épisacro-iliaques are an affection of the adults.

Fiessinger considered these lipomas a menopausal disorder. And Copeman considered a water retention-endocrine origin.

Mainly lipomes épisacro-iliaques present as a BILATERAL FINDING

Most of the times it is a bilateral finding. Ries found 231 bilateral vs 86 unilateral and Hittner 35 bilateral vs 15 unilateral.

Of 12 of Sicard’s cases 10 are bilateral. He mentions that if they present bilaterally, they are often SYMMETRICAL. Sometimes they are multiple. Next to a big one, they found one or two smaller ones.

Most of these lipomes épisacro-ilaques are discovered by chance, most of them are absolutely painless and do not reveal any functional disorder.

Ries indicated that from the 317 patients 38% presented lumbosacralgia.

Macroscopically: not much to say

Anatomically, these lipomas do NOT present any particular character. The lipomes épisacro-ilaques are round masses, the size of a hazelnut or a nut, embedded in the cellular tissue of the buttocks. They are found in the posterior surface of the sacroiliac joint lateral to the Micahelis rhombus. They lay deep. They did not manage to show a pedicle or an attachment to the periarticular structures. They are easy to be enucleated; only in very fat women it is sometimes difficult to discover them during intervention.


The histological examination is a bit more demonstrative. In 6 of Sicard and Lord’s cases, the lipoma consisted of a cluster of fat cells separated by a RARE CONNECTIVE TISSUE; the rest had a normal appearance. In 3 cases they noted a “change” in the connective cells.

Dr. Brux described it as: “une modification des cellules graisseuses qui redevienment conjonctives et tendent à s’entourer dún réticulum fibreux” [a modification of the fat cells which become conjunctival and tend to surround themselves with a fibrous reticulum].

In 2 cases there were quite a few nervous filaments.

They couldn‘t conclude anything form the findings in any way.

In 1933 Becke had already drawn attention to the very frequent existence of the nerve filaments. He related it with being a neurolipoma and the compression could be the cause of pain.

Copeman and Pugh compared histological examinations between painless and painful lipomas. It seemed to them that the painless lipomas had fat cells occupying spaces delimitated by a thin capsule. The painful lipomas seemed to present edema, without any inflammatory signs.

Florentin and Louyot found 3 cases, epithelioid cells organized in a way that presented similar characteristics to the ASCHOFF nodule. In one case the lipoma was the seat of a small necrotic focus of 6 to 8 mm.

Etiopathogenic hypothesis: What are the lipomes épisacro-ilaques?

The etiopathogenic hypothesis to explain the relation with the lipomes épisacro-iliaques and the pain syndrome are poorly supported by the histological findings, which show too variable results and often too normal findings.

The observation in certain cases of INTRA-LIPOMATOUS nerve filaments may lead to the diagnosis of a NEUROLIPOMA (then the nodule would be a consequence of the disease, but this is not supported by the fact that, after excision of the lipoma, there is a pain relief).

The proximity of the posterior branches of the sacral nerves should be the same in the case of the presence of non-painful lipomas.

Sicard thought that Copeman‘s theory relaying on his own anatomical observations is debatable, but for sure an original theory. Copeman stated that the nodules would have a double sensory and vasomotor innervation. The pain would be related to the compression of the sensory cells by the turgor of the edematous fat cells within the capsule. The edema would be the result of a vasomotor disturbance. It would be a dysfunction in the normal physiological mechanism of water storage of the fatty tissue, maybe by an endocrine disturbance.

Clinically the lipomes épisacro-ilaques present as pain

It is presented as a low back pain syndrome. It can have a progressive appearance; sometimes the pain is not localized where the lipoma lies. Mainly it is located in the lumbosacral region and usually radiates towards the buttocks.

It can be continuous, barely calmed by resting. It can be tolerable by the patient or present as a very incapacitating pain.

The palpation of the lumbosacral interline is not painful, it is sometimes associated to the lumbar muscle spasm.

While exploring the region the doctor can discover this elastic, rubbery and rolling under the fingertips nodule. These deep nodules can be painful or not. Both sides should always be explored, since they are often BILATERAL.

Sometimes it presents a sciatalgic syndrome with certain PARTICULARITIES: certain rebel characteristics, the pain starts from the lumbo-sacral region, it radiates to the thigh often until the knee, but never to the FOOT.

The Lasègue sign is often absent. The reflexes are normal.

When the lipoma is rolled over the deeper planes, the pain is arisen by the usual character (this is a great value sign). It is more clearly done in ventral decubitus. And it is more relevant if a painless lipoma can be found in the other side.

The problem is to find the relationship between the lipoma and the pain syndrome and not to mistake it with other pathologies such a local abscess.

The INTRA-LIPOMATOUS INJECTION with novocaine has been proposed by Copeman. If the relief LASTS LONGER than ordinary local anesthesia, for example several days, then it can be said that THE LIPOMA was THE CAUSE of the syndrome.

The sign Sicard said is the most valuable is when the lipoma is sensitive to pressure, and if the lipoma rolled with certain pressure, it provokes irradiation pain to the lumbosacral region or leg.

 SICARD and LORD’s observations of lipomes épisacro-ilaques

Of the 12 cases of Sicard, 5 had lumbosacralgia and 7 sciatica. All had accepted the intervention (knowing the possibility that it would not cure them, but most of them had previously underwent many other treatments without relief).

In 3 cases, it was a recurrence of a sciatica previously related to a herniated disc. The removal of the fatty nodule was accepted by the patient, who refused to get reintervention of the lumbar disc. To Sicard’s surprise, a VERY STRONG PAIN in 3 patients disappeared INMEDIATELY and they were “symptom-free” at least for 2 years.

The “first case“ of doctor SICARD

lipomes épisacro-iliaques

A 42-year-old woman. One of the physicians from Sicard had operated her on of a right disc lumbar hernia of L4-L5 and she returned two years afterwards with a left sciatica for 2 months that kept worsening. It seemed to Sicard’s team that this was a recurrence of the herniated disc of the opposite side. Nevertheless, the patient strongly REFUSED to be operated on of the spine. Then, since she presented lipomes épisacro-iliaques bilaterally BUT just one side (the side of the sciatica) was clearly painful. They proposed her to practice an exeresis of the nodule. The same evening of the operation, the pain DISAPPEARED. The freedom of pain lasted at least (for the time of publication) 5 years. This was Dr. Sicard’s first case. It marked a switch to them. The technique was simple, once the skin was opened the lipoma elucidated clearly from the surrounding tissue.

If there is more than one lipoma, Dr. Sicard suggested removing them all. They left drainage. They preferred general anesthesia, since a local anesthetic may be a difficulty in localizing the nodule, especially in obese patients.

Copeman practiced an intra-nodular injection of novocaine sometimes with complete relief.

In 1951 Rouhier presented 3 cases similar with the conclusions of Copeman in the Académie de Chirurgie.

Hittner claimed 45 healings from 50 patients.

Dr. Sicard had 12 cases, 7 with complete relief; some others just presented a certain degree of relief.

They were prudent with the conclusions and admitted that there are too many mysterious facts about this pathology.

Published in July 2018 by Marta Cañis Parera   ORCID iD icon


  • SICARD A, LORD G. [Episacroiliac lipomas and lumbo-sciatica]. Presse Med. 1952 Jul 26;60(50):1073-4. Undetermined Language. PubMed PMID: 13026891.
  • HITTNER VJ. Episacroiliac lipomas. Am J Surg. 1949 Sep;78(3):382. PubMed PMID: 18139061.
  • Copeman WSC. Fibro-fatty Tissue and its Relation to “Rheumatic” Syndromes. British Medical Journal. 1949;2(4620):191-197
  • ROUHIER G. [Painful lipoma of the sciatic notch and of the para-sacral region]. Mem Acad Chir (Paris). 1951 Apr 25-May 2;77(14-15):481-2. Undetermined Language. PubMed PMID: 14852593.