1937 Ries

Dr. Ries got intrigued by a patient with disabling low back pain that got relieved by removing surgically a fatty tumor in the sacroiliac area, he called it episacroiliac lipoma.

He then decided to explore 1000 patients to find out more about these lipomas that are also known as back mice.

Notes on the article of:

Ries E.

Episacroiliac lipoma.

Am J Obstet Gynecol 1937; 34:492-8.

This work was reported at a meeting of the Chicago Gynecological Society, October 23, 1936.

Emil Ries’ unique case about episacroiliac lipoma

Dr. Ries starts that article mentioning that he thinks that the observation and investigation of a unique case of a woman has lead him to the establishment of a clinical and pathological entity that seemed to be un-described in medical literature. And it has a great practical importance with the symptom of backache. He and his colleague applied the name of episacroiliac lipoma. They insisted that the connection of this group of tumors with backaches should receive wider attention.

The case of 30-year-old Mrs N.K. of Dr. Ries

episacroiliac lipoma back mice

The first patient, a 30-year-old hotel worker that had some obstetrical past history (tubal pregnancy, salpingitis, hemorrhoids and fistula-in-ano), was visited by Dr. Ries with DISABLING PAIN IN THE BACK extending to the right hip and thigh which woke her up in the morning lasting all day. Bending over increased it.

General physical examination was normal. Examination of the sacral region showed a 3 by 2 cm elliptical tender tumor placed transversely over the right sacroiliac joint and a symmetric one on the left side. It had an elastic consistency as a fatty tumor. On repeated examination patient located her backache at these two points. The two tumors were removed surgically. The patient reported freedom of pain. They designated the tumors as “episacroiliac lipomas“.

Had other cases been overlooked? Ries and Lifvendahl on the search…

After the intriguing case of this woman, Dr. Ries, with the help of Dr. Richard Lifvendahl, undertook the examination of 1,000 persons at random dispensaries in order to find if similar cases existed and had been overlooked.

Ries and Lifvendahl explored the back of 1,000 persons

Statistic results of the 1,000 explored persons by Ries and Lifvendahl

episacroiliac lipoma back mice

-250 males and 750 females

-309/1,000 had backache in the lumbosacral region

-159/309 had no tumours

-317/1,000 had similar tumours as reported above: 46 males and 217 females, 223 white and 94 colour, 150 complained of backache and 167 had no backache, 131 were spontaneously painful, and 231 tumours were bilateral.

episacroiliac lipoma or back mice

-Age distribution of the 317: under ten (7), to twenty (13), to thirty (67), to forty (102), to fifty (80), to sixty (29), and above sixty (19).

-40 pregnant women: 22 had tumours, 14 had tumours but no pain, 4 had episacroiliac lipoma and pain.

Ries emphasized that there wasn’t any case of “adiposis dolorosa” of Dercum.

They couldn’t do a complete examination of the entire body in all persons.

The Ries’s examination method to find the episacroiliac lipoma

The subject sitting on an examination table (bending forward) or lying (with the sacral region exposed). The tips of the examiner’s fingers pass over the sacral and iliac regions. Important to exclude the sacral bony prominences. They count positive the tumors that could be moved freely.

Dr. Ries warns that the majority of patients with the “episacroiliac tumours” would never be suspected UNLESS a SYSTEMATIC SEARCH, such as they carried out, had revealed.

The examination of the “sensitive tumours”. Ries’ technique.

episacroiliac lipoma or back mice

If the patient declared the tumour sensitive to the touch by the examiner, they repeated examination by examining the surrounding territory and then the “sensitive tumour” back. Then a tumour is put it in the “sensitive tumour” category if the patient identifies the area POSITIVELY on REPEATED palpation to be sure the sensitive area is the area of the “sensitive tumour”.

When patients say “this is the point!”

Dr. Ries was aware that 159 people of the 1,000 examined that presented backache didn’t have any “sensitive tumour“, and that 167 persons presented tumours but they didn’t have any backache. Anyway he was intrigued by the backache cases that seem to be related to the “sensitive tumours”.

Mr Ries says that it is a striking experience when the patients with the “sensitive tumours” recognize “the area as the seat of their pain” immediately. And the handling, pressing or moving of these tumours clearly elicited promptly the pain.

Moreover, in some patients the pressure on these episacroliliac lipomas causes pain to radiate in different directions.

About the aspect of the episacroiliac lipoma

Shape: They are cylindroid (placed transversely) or round.

Size: The largest was of a “silver dollar size as thick as little finger”. The smallest of 1cm of diameter.

episacroiliac lipoma or back mice

Consistency: The consistency is of an elastic lipoma, or a soft fibroma.

The skin: the skin is always movable over the tumors, the tumors “slip under the skin”.

Pain character: the patient described it as an “ache”.

Localization: mainly on the area of the sacroiliac joint. Specially 5cm from the “sacroiliac dimples”.

Symmetrical: in most cases “these growths” were symmetrical and of similar shape in both sides. In a few cases, one side was larger than the other. There were persons that have pain only on one side. (in rare cases they found more than two tumors).

Unawareness: most patients were unaware of the tumors (except for 3).

Treatment of the episacroiliac lipoma

They treated the episacroiliac lipomas by injection (2% novocaine) or by excision in 20 patients. Dr. Ries admits that it is too short a time to report on remote results.

episacroiliac lipoma or back mice

2% novocaine injection: They injected the tumour or around it. The relief was strikingly rapid. Many patients after injection bent over and straightened out and declared comfortable (striking considering that some had been under other treatments for long time without previous relief).

-SOME PATIENTS REPORTED RELIEF on longer duration than the usual effect of the local anaesthetic (at the moment of article publication, some patients lasted for weeks).

Surgical excision (usually under local anaesthesia): Specially on large tumours or in tumors where injection of novocaine only gave temporary relief. Dr. Ries made emphasis that the tumor seemed to “shell out” and showed little bleeding.

Ries’s pathological findings

-The episacroiliac tumours are more or less rounded cylindroids.

-They have distinct fibrous capsules that consist of dense fibrous tissue.

-In one case a small nerve has been found running through the middle of the tumour (they say they were investigating the relation with neurolipomas).

Published March 2018 By Marta Cañis Parera   ORCID iD icon



Reis E. Episacroiliac lipoma. Am J Obstet Gynecol 1937;34:492-8.