The article was published in an Italian magazine and it does NOT HAVE any FIGURE. But it presents a short literature review about the episacroiliac lipoma symptoms (about back mice) and etiopathogenic characteristics and 4 case reports. It provides a rather complete reference review.
Carninci and Campailla present just 4 medical case reports that they operate on, with resolution of the painful patients (some of the patients presented NON-PAINFUL nodules). They removed surgically silent and painful nodules that microscopically were reported as lipomas (and presented not pathological findings that differ from each other).
They want to recall attention about what it seems to be a rather banal entity BUT, nonetheless, it can cause lumbalgia or lumbosciatalgic very painful syndromes.
Baciu (1969) proposed the term “the lumbosciatalgia of Copeman-Ackerman type” to call this entity.
They admit they cannot know the etiopathogenic explanation why some nodules are silent and others are painful. But they admit that the surgical excision can be a cure.
I LIPOMI EPISACROILIACI
By E. Carninci and E. Campailla
There are several lumbalgic and lumbosciatalgic syndromes. Among the less common one can find an apparently banal and modest lesion: small nodules of adipose tissue that resemble lipomas (back mice).
Ries (1937) was the first one to study their clinical significance. These nodules were also anatomically studied by Copeman and Ackerman. The authors admit it is not a new entity but warn that its importance in the pathogenesis of some pain syndromes does not seem to be correctly assessed.
These lipomas (back mice) are located in the region corresponding to the surface around the sacroiliac joint. They seem to be free without connection with the periarticular tissues. These nodules have been called episacroiliac lipomas.
Macroscopically, they present the classical characteristics of a lipoma. They are relatively small (“da una nocciola a una noce”) even when they are found in obese patients.
Sometimes they are UNILATERAL, but often they are BILATERAL and even symmetric (Ries, 1937; Hittner, 1949; Donati and Bidone, 1952), sometimes they are multiple and of different volume (some bigger and some, smaller). Ries even mentions that some individuals could present 5 or 6 nodules.
IT SEEMS TYPICAL that they present DUPLICITY, BILATERALITY AND SYMMETRY.
They are more frequently found in women (Ries, Hittner, Sicard and Lord (1952), and Copeman).
These nodules can be sometimes PAINFUL and sometimes SILENT, sometimes painful only on palpation. But it is noticeable that, in both cases, the previously mentioned morphological characteristics remain unchanged.
The pain usually starts subtly over many years and it is mainly localized in the lumbosacral region, sometimes with radiation to the gluteal region, or in the form of sciatic radiation, sometimes reaching the knee, and never the foot (according to Baciu, 1969).
Histological examinations do not provide any data that COULD EXPLAIN THE ASSOCIATION of lipoma with the pain syndrome. Nevertheless, Copeman and Pugh observed certain difference between the PAINFUL LIPOMAS and the SILENT ONES: THEY OBSERVED A DISCREET EDEMA. Becke (mentioned in Sicard and Lord’s work) observed some nerve threads suggesting the presence of a neurolipoma. Suggestion that the pain could be explained by nerve compression. However, Becke’s finding had not been confirmed by other authors.
That’s why the etiopathogenesis remains OBSCURE. The opinion of the various authors who dealt with is discordant.
Paillard (quoted by Lord and Sicard) recalled that women present a more marked adiposity of the retrosacroiliac region.
Adulthood is a period of more affection; Fissinger (quoted by Sicard and Lord) thought that it could be explained by a DISTURBANCE of the lipid metabolism in concomitance with the menopausal changes. For Copeman, it is especially related to the disturbance of the WATER metabolism and BALANCE, especially in the menopuasal zone. BLANCH (quoted by Sicard and Lord) related it to the protein metabolism.
Copeman and Ackerman also mention that sometimes the fatty nodules could herniate through the fascial layers due to trauma.
The overall reason for the ONSET of these lipomas in the sacro-iliac site is still unknown, and also the reason why sometimes they become so painful in such a way as to provoke a very impressive clinical symptomatology that is TOTALLY disproportionate to the anatomo-pathological characteristic of these lesions.
But there is no doubt that the lumbago and the lumbosciatalgic syndromes are related to the presence of these lipomas.
It is demonstrated that the symptoms disappear by just the simple surgical excision of them (Hittner, Copeman, Rouhier, Sicard and Lord, Donati and Bidone, Katz (1950), and Berck).
Differencial diagnosis of the episacroiliac lipoma symptoms
Due to the difficulty to differentiate the different lumbalgic syndromes, and the presence of silent nodules, it is useful to use the NOVOCAINIC INFILTRATION. Therefore, if the injection STOPS the pain, it will be evident that these are the cause.
Therapy
According to the own authors’ experience, the definitive treatment is surgery (that does not present many complications); on the contrary, Copeman stated that the cure could be reached by detaining and lacerating the fat.
Cases
They present 4 cases of episacroiliac lipomas. Three female and one male.
The male himself felt a small swelling in the right sacro-iliac site, indolent spontaneously and on palpation. They removed it and it happened to be lipomas.
One of the women presented silent bilateral lipomas, and the other presented lumbar pain with radiation to the buttock and the thigh.
The 4 cases underwent surgical removal and, microscopically, the nodules were found to be lipomas.
For the symptomatic patients, the surgery resulted in resolution of the painful syndromes.
The authors say that they could conclude that what they encounter completely agrees with the literature data.
Published in November 2018 By Marta Cañis Parera 
Reference
-I LIPOMI EPISACROILIACI. E. Campailla and E. Carninci. L’Arcispedale S. Anna di Ferrara, 23, 379-383, 1970