See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/262192076 Giant buttock lipoma with an atypical presentation as a sciatic hernia - case report Article in Acta reumatologica portuguesa · May 2014 Source: PubMed CITATIONS READS 5 108 5 authors , including: Rui Pimenta Ribeiro Rui Matos Centro Hospitalar Medio Ave; Hospital Lusiadas Porto; Hospital Privado de Braga Centro Hospitalar de São João 10 PUBLICATIONS 37 CITATIONS 27 PUBLICATIONS 24 CITATIONS SEE PROFILE SEE PROFILE Rui Peixoto Pinto St. Maria -Porto Hospital 121 PUBLICATIONS 129 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Atypical Orthopaedic tumors View project Tendências Epidemiológicas das Fraturas do Fémur Proximal na População Idosa em Portugal View project All content following this page was uploaded by Rui Matos on 28 February 2019. The user has requested enhancement of the downloaded file.
iMAgENS EM REUMATOLOgiA Giant buttock lipoma with an atypical presentation as a sciatic hernia – case report Rui Pimenta 1 , Rui Milheiro Matos 1 , Rita Proença 1 , Hernâni Rocha Pereira 1 , Rui Pinto 1 ACTA REUMATOL PORT. 2014;39:91-93 IntRoductIon formed on the patient, showing a well defined large mass, in the left gluteal region between the gluteus ma- Lipomas are soft-tissue tumours deriving from the pro- ximum and minimum, with similarities to fat tissue, liferation of mature adipocytes. They have benign cha- measuring 12x13x10 cm (longitudinal diameter, trans- racteristics and a mesenchymal origin, representing the verse and anteroposterior), occupying the posterior most common soft-tissue tumours of adulthood 1 . They side of the left hip joint, extending to the obturator fo- can reach considerable size prior to diagnosis till they ramen, causing deviation of the pelvic structures (Fi- become symptomatic. The authors report a case of a gure1). An arteriography was carry out and was not ob- patient in whom a giant buttock lipoma presents itself served any tumour blush or invasion of the gluteal ves- as a sciatic hernia. Magnetic resonance imaging revea- sels, obturator vessels or others. The tumour was ho- led a large intra- and extra-pelvic fat mass throughout mogeneously iso-intense with fat. Appart from its size the sciatic notch. The tumour was surgically removed and deep position, there were no other signs for alarm, through an Kocher-Langenbeck approach. Successful although an atypical lipoma or well differentiated lipo- and safe removal of this large benign pelvic tumour was sarcoma could not be excluded. achieved, although the patient still reveals neurological Despite the benign features of the lesion, consistent sequelae up to this day. with giant lipoma, the patient underwent surgery to perform a total excision of the tumour mass, due to the compression of adjacent structures, including the blad- case study der (which was displaced anteriorly) and sciatic nerve. A Kocher-Langenbeck approach was performed and A 55-year-old woman with left low back pain, pares- the superficial part of the tumour was resected (Figure thesia and hypoesthesia in the territory of L5 and S1 2). The sciatic nerve was identified and isolated deeply roots, with decreased muscle strength (3 / 5), with to the sciatic notch, with progressive blunt dissection about one year of evolution. The patient referred pol- of the tumour. A partial section of the hip rotators was lakiuria without abdominal or pelvic discomfort. No performed allowing the detachment of the deeper part pelvic or spine surgery was reported, and she was not of the tumour adjacent to the obturator foramen. The medicated in any way. In addition, the patient had no tumour was removed, with a total weight of 548 grams. relevant medical or family history except for diabetes Its histopathological examination had no signs of ma- mellitus. No lump was detected and the laboratory test lignancy, without lobulated fatty tissue, macroscopic or results were normal. histological evidence of haemorrhage, necrosis, lipo- An electromyography (EMG) of lower limbs and blasts or malignant cells. This confirmed the diagnosis magnetic resonance imaging (MRI) of the lumbar spi- of a giant lipoma. ne was performed, and showed axonal injury of the left L5 root on EMG, without root or spinal cord compres- Results sion, visible on MRI, to justify the low back pain and the axonal lesion on the EMG. A pelvic MRI was per- After 4 days of uneventful hospitalisation the patient went home, with permission to partial weight bear and 1. Department of Orthopedic Surgery, Centro Hospitalar de São walk with crutches for 2 weeks, till the pain dissapears. João, Porto, Portugal ÓRgÃO OfiCiAL DA SOCiEDADE PORTUgUESA DE REUMATOLOgiA 91
Giant buttock lipoma with an atypical presentation as a sciatic hernia – case report FIGuRe 1. MRI (coronal section), showing the large tumour invading the pelvis FIGuRe 2. Macroscopic view of the lipoma No adjuvant treatment was given. Postoperativelly the patient maintained complaints the sciatic foramen 4 . of hypoaesthesia, paraesthesia and decreased muscle When a patient complains with sciatic pain, the strength (3 / 5). She was followed in outpatient clinic, physician has to be able to exclude disc herniation with having performed approximately 4 months of physi- radicular compression, hip pathology, muscular pain cal therapy, with progressive clinical improvement. and other compressive causes in the lumbar column Two years after surgery, the patient has no pain and no and the pelvis region. Sometimes tumours are detec- bladder complaints. However, she maintains a slight ted in regular health screening examinations. If a big deficit in muscle strength (4/5) with hypoaesthesia and mass as a lipoma is located in the retroperitoneal spa- paresthesias on the left foot. A two month post-surge- ce, it becomes difficult to detect once the symptoms are ry MRI revealed a small remnant of the lipoma tissue late and nonspecific, so they can grow slowly, reaching of about 15x25 mm. The EMG carried out six months a considerable size before being diagnosed. There are following the surgery was consistent with sequelae of usually no laboratory abnormalities and the MRI ena- severe axonal injury of the left common sciatic nerve. bles the differentiation between benign and malignant No evidence of tumour recurrence was reported at 2 tumours, so its characteristic imaging findings are cru- years of follow-up. cial to distinguish fatty tumors such as lipomas or li- posarcomas, once they are differential diagnosis. His- topathologic examination, however, is necessary to ex- dIscussIon clude liposarcoma. Ultrasound-guided fine needle bio- psy can be performed to exclude malignancy, revealing Superficial lipomas are very commonly benign adipo- benign tumour tissue 2 . se tissue tumours. In contrast, deep seated lipomas are The treatment of these big lipomas is the total re- extremely rare and must be carefully distinguished section of the tumour mainly because its compressive symptoms. Osteotomies of the pelvis 5 or combined from well differentiated liposarcomas for appropriate treatment and follow-up 2 . Lipomas grow slowly and one-stage transabdominal and posterior transgluteal surround the structures next to it, and when in the pel- are described to be necessary to achieve total resection vic region, displacement of organs, such as bowel, can of the tumour in some cases 6 . High-resolution MRI is occur 3 . a useful tool in the management of these tumours be- There are few reported cases of such big lipomas in cause it allows the surgeon to visualize the anatomical pelvic cavity. In our case the mass occupied both the relationships of the tumour to the sciatic nerve. These inside and outside of the pelvic cavity. As described in imaging technology advances, will provide surgeons a other articles we could not clarify whether its primary method to predict definitively which sciatic notch tu- site was the pelvic cavity or the left buttock. Conside- mours displace rather than directly involve the sciatic ring the reported cases, we thought that the mass ex- nerve, and therefore indicate which tumours can be tended from the buttock to the pelvic cavity through resected safely and completely 6 . The operative mana- ÓRgÃO OfiCiAL DA SOCiEDADE PORTUgUESA DE REUMATOLOgiA 92
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