Diagnostic imaging of lipoma arborescens

Objective. The imaging characteristics of lipoma arborescens using plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) are described. Design and patients. Five patients with a diagnosis of lipoma arborescens are presented. Three had monoarticular involvement of the knee joint. In the remaining two patients both knees and both hips, respectively, were affected. All patients were examined using plain radiographs and MRI. CT was employed in two cases. Results and conclusions. A conclusive diagnosis with exclusion of other synovial pathologies having similar clinical and radiological behaviour can be achieved on the basis of the MRI characteristics of lipoma arborescens. The aetiology of lipoma arborescens remains unknown, but its association with previous pathology of the affected joints in all our patients supports the theory of a non-neoplastic reactive process involving the synovial membrane.     

Lipoma arborescens of the glenohumeral joint causing bone erosion: MRI features with gadolinium enhancement

Lipoma arborescens is a rare benign intra-articular lesion that principally affects the knee joint. We present a case of lipoma arborescens involving the glenohumeral joint and associated with prominent large bony erosions. The gadolinium diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (MRI) features of this lesion are also described. The characteristic MRI findings permit precise preoperative diagnosis of this rare condition even if it occurs in an atypical location and there are confusing radiological findings.     

MR findings in lipoma arborescens of the knee: our experience

PURPOSE: This paper describes the role of MR imaging in the identification of the different macroscopic patterns of lipoma arborescens. MATERIALS AND METHODS: Between June 1995 and January 2004, a total of 6387 MR examinations of the knee were retrospectively assessed for the presence of lipoma arborescens. The MR examinations were performed using a superconductive 0.5 T MR unit with a transmitting/ receiving coil dedicated for the extremities. The MR images were acquired with SE T1-weighted, GE T2-weighted and STIR sequences in sagittal, coronal and axial planes with 3-mm thickness and 1-mm gap. RESULTS: Lipoma arborescens was identified in 9 patients (mean age: 36 years). In 2/9 cases a localized lipoma arborescens was detected as a well-marginated single nodule on the suprapatellar bursa without irregularity or synovial hyperplasia. In the remaining 7 cases diffuse lipoma arborescens was identified on the wall of the suprapatellar bursa. In one case of diffuse lipoma arborescens there was involvement of both knees. In all cases the MR findings were verified at surgery and the final diagnosis was made by histological examination. CONCLUSIONS: MR imaging shows a high accuracy in the identification and characterization of lipoma arborescens, due to its multiplanar capabilities and high contrast resolution. MRI allows correct evaluation of size and grade, accurate treatment planning and effective follow-up, avoiding the need for synovial biopsy.     

肩关节损伤的MR影像诊断

目的 探讨常规MRI和MR间接关节造影对肩关节损伤的诊断价值.方法 回顾分析经关节镜证实的90例肩关节损伤患者肩关节常规MRI和MR问接关节造影表现,其中肩袖病变组57例、盂肱关节不稳组33例.对常规MRI和MR间接关节造影诊断结果进行Fisher确切概率法比较.结果 (1)肩袖病变组中MR间接关节造影37例,显示部分撕裂10例,1例漏诊;显示完全撕裂17例,2例误诊,7例肩袖无撕裂.MR间接关节造影显示部分撕裂的敏感度、特异度、准确度分别为90.9%(10/11)、92.3%(24/26)、91.9%(34/37);显示完全撕裂的敏感度、特异度、准确度分别为89.5%(17/19)、94.4%(17/18)、91.9%(34/37).MR间接关节造影诊断肩袖部分及完全撕裂的敏感度及准确度均高于常规MRI(P<0.05).(2)盂肱关节不稳组中,盂唇损伤26例,Hill-sachs病变27例、反Hill-sachs病变2例、骨陛Bankart损伤7例、关节囊损伤18例.间接关节造影20例,显示盂唇损伤14例,1例漏诊,5例正常.MR间接关节造影显示盂唇损伤的敏感度、特异度、准确度分别为93.3%(14/15)、100.0%(5/5)、95.0%(19/20).前者诊断盂唇损伤的敏感度及准确度明显高于常规MRI(P<0.05).结论 MR检查特别是MR间接关节造影能够准确显示肩关节常见病变及相关组织的病理发展过程,为临床诊断及治疗提供影像学依据.     

Lipoma arborescens affecting multiple joints

Lipoma arborescens is a rare benign intra-articular lesion of unknown etiology that usually involves the suprapatellar pouch of the knee joint. Clinically, the most common finding is a slow-growing painless swelling, accompanied by intermittent effusion of the joint. We report a case of a multifocal lipoma arborescens localized in the knees and the hips in a 24-year-old man, initially mimicking an inflammatory arthropathy. The diagnosis of lipoma arborescens was made by magnetic resonance imaging of the hips and the knees. Under arthroscopic guidance, the synovial biopsy of the right knee disclosed the specific histological signs of lipoma arborescens. As far as we know, this is the third case of multifocal lipoma arborescens reported in the English literature.     

Bilateral lipoma arborescens of the knee in a child: a case report

We report a case of childhood lipoma arborescens of both knee joints who had been erroneously diagnosed to have initially acute rheumatic fever and subsequently oligoarticular juvenile rheumatoid arthritis. She had taken anti-inflammatory medication for 8 years without remission of the effusion. Magnetic resonance imaging (MRI) and synovectomy revealed the diagnosis of lipoma arborescens. Lipoma arborescens should be kept in mind in the differential diagnosis of refractory chronic joint effusion and synovial hypertrophy in the childhood period, and MRI yields the correct diagnosis in this setting.     

Lipoma arborescens of the peroneal tendon sheath

Lipoma arborescens or synovial lipomatosis is a rare disorder characterized by mature fat infiltration of hypertrophic synovial villi, most frequently affecting the suprapatellar pouch of the knee. Involvement of the synovial tendon sheath is extremely rare with only a few reported cases in the literature. We present a case of lipoma arborescens involving the peroneal and flexor tendons sheaths of the ankle, review the few reported cases to date, and discuss MR imaging features of this rare entity.     

Acromioclavicular joint cyst: nine cases of a pseudotumor of the shoulder

Objective (1) To analyse the imaging appearances of nine patients with acromioclavicular joint cysts presenting as shoulder masses for tumor staging with operative, histopathological and joint aspiration findings.Design and patients Retrospective review of imaging and correlation with clinical, operative and surgical notes. Images were reviewed by two musculoskeletal radiologists by consensus. Nine patients who presented clinically with a shoulder mass were evaluated by radiographs (n=9), ultrasound (n=1), conventional arthrography (n=3), MRI (n=6; with direct MR arthrography n=2, indirect MR arthrography n=4).Results All patients had a focal mass superior to the AC joint, with a size ranging from 1.5 cm to 6 cm and a mean of 3.27 cm. Correlation was available with surgery (n=7), histopathology (n=2) and cyst aspiration (n=2). Two patients were managed conservatively. Geyser sign was positive in all three arthrograms. All MRIs revealed extensive rotator cuff tears with a column of fluid extending from the glenohumeral joint through the rotator cuff tear into the acromioclavicular joint and acromioclavicular cyst. Chondrocalcinosis was seen in the acromioclavicular joint cyst (n=2) and in the glenohumeral joint (n=1). Aspirate in two patients contained calcium pyrophosphate dihydrate crystals.Conclusion Acromioclavicular joint cysts may present as a tumor mass. They are associated with extensive rotator cuff tears and there is usually communication of the cyst with the joint space. This feature excludes a diagnosis of tumor. AC joint cysts may be associated with calcium pyrophosphate dihydrate deposition disease.     

Imaging evaluation of meniscal injury of the knee joint: a comparative MR imaging and arthroscopic study

To evaluate the efficacy of MR imaging in the diagnosis and classification of meniscal tear of the knee joint, we retrospectively characterized the MR features of 78 meniscal tears in 148 patients according to the Mesgarzadeh's criteria. The results showed that the sensitivity and specificity for meniscal tears were 92% and 87%, respectively. Type VI meniscal tear was the most common type, especially in displaced meniscal tear. MR is a reliable diagnostic tool for meniscal tears and associated cruciate ligament injury.     

Lipoma arborescens of the glenohumeral joint: a possible cause of osteoarthritis

Lipoma arborescens is a very rare intra-articular lesion characterized by villous lipomatous proliferation of the synovium, usually involving the knee joint. To date, in the literature, there has been only one reported case of lipoma arborescens in the glenohumeral joint. But, the authors treated the patient conservatively and reported only the magnetic resonance imaging (MRI) findings. We report a case of a patient with lipoma arborescens involving the glenohumeral joint. To our knowledge, this is the first reported case of lipoma arborescens involving the glenohumeral joint managed by arthroscopic synovectomy. We identified reactive bone erosions and arthritic changes in the humeral head in a 22-year-old male patient by arthroscopy.     

The role of meniscal root pathology and radial meniscal tear in medial meniscal extrusion

Objective The purpose of our study was twofold: to better understand the relationship between medial meniscal extrusion (MME) and degenerative joint disease (DJD), and to determine whether a relationship exists between MME and medial meniscal root (MMR) pathology, radial tear and joint effusion.Design and patients Two hundred and five consecutive MR imaging examinations of the knee were prospectively evaluated, regardless of indication, for the presence and degree of MME, medial compartment marginal osteophytes, medial compartment articular cartilage loss, joint effusion, medial meniscal tear and MMR pathology. MME 3 mm was considered abnormal. All studies were performed using a 1.5 T GE Signa MR unit with a quadrature knee coil. The standard protocol included oblique sagittal, coronal and axial imaging.Results We found a strong association (P<0.0001) between 3 mm MME and medial joint line osteophytosis (77%), medial compartment articular cartilage loss (69%), MMR pathology (64%) and radial tear (58%) when compared with knees without these findings. Fifty-one percent of cases with a moderate/large joint effusion had <3 mm MME. We found that 20% (31/155) of patients with minimal or no evidence of DJD had 3 mm MME. Of this group, 62% (19/31) had either MMR pathology and/or radial tear, 13% (4/31) had joint effusion as their only abnormality and 6% (2/31) had a normal examination (other than the presence of MME). The remaining 19% consisted of three cases of different types of meniscal tear and three cases of small joint effusions but no other detectable pathology.Conclusion MME 3 mm is strongly associated with DJD, MMR pathology and radial tear. A significant number of cases with no or minimal evidence of DJD (20%) had 3 mm MME, suggesting that MME precedes, rather than follows, the development of DJD. We also found that joint effusion was not strongly associated with 3 mm MME.This paper was presented at the 2003 ARRS meeting     

膝关节半月板损伤的MRI与关节镜对照研究

目的评价MRI在膝关节半月板撕裂诊断和评级中的价值。方法参照Mesgarzadeh标准对76位患者78个撕裂半月板的MR影像作回顾性分析,3位MRI主治医师在不知道关节镜检查结果的情况下独自阅片,按Mesgarzadeh的分级标准确定半月板撕裂的类型并记录评定结果,包括联合的前交叉韧带撕裂。结果MRI诊断半月板撕裂的敏感性和特异性分别为92%和87%,Ⅵ型是半月板撕裂中最常见的类型,尤其在发生移位的半月板撕裂中最常见。结论MRI是半月板撕裂伤和交叉韧带损伤的可靠诊断工具。     

An unusual case of extraarticular lipoma of the knee joint

Lipoma of the knee joint is a rare disease and most cases are lipoma arborescens within the joint. Here we report a case of true extraarticular lipoma of the knee.     

MR imaging of synovial tumors and tumor-like lesions

The clinical diagnosis of synovial tumors and tumorlike lesions is difficult, and radiographic findings may establish a confident diagnosis only in some cases. MR imaging has become the modality of choice in evaluating these lesions, because with it a presumptive diagnosis can be made in most cases. Our goal is to review the MR features of pigmented villonodular synovitis, giant-cell tumor of the tendon sheath, synovial chondromatosis, synovial hemangioma, lipoma arborescens, synovial cysts and synovial sarcoma, emphasizing those findings that suggest a specific diagnosis.     

Extra-articular soft tissue ganglion cyst around the knee: focus on the associated findings

The aim of this study was to evaluate MR imaging findings of the associated findings in surrounding tissues of the extra-articular soft tissue ganglion cysts around the knee. We retrospectively reviewed MR images of 30 patients who had surgically confirmed extra-articular soft tissue ganglion cysts around the knee with focus on the associated findings in surrounding tissues, such as muscle, subcutaneous fat, bone, and nerve. The most common associated finding was the visualization of channel between ganglion cyst and the joint, which was demonstrated in 20 cases (continuous type in 12 cases and discontinuous type in 8 cases). Other associated findings were seen in 15 cases; pericystic edema (n=9), bony remodelling (n=3), and nerve involvement (n=3). The bony remodelling involved the proximal metaphysis of tibia in all 3 cases. Two patients with nerve involvement had deep peroneal nerve in subacute phase and one involved common peroneal nerve in chronic phase. The MR imaging is a useful imaging modality to evaluate the associated findings in extra-articular soft tissue ganglion cysts around the knee. The evaluation of these associated findings is helpful for the differentiation of ganglion cysts from other cystic lesions around the knee.     

膝关节交叉韧带损伤的MRI诊断

目的 :探讨MRI对膝关节交叉韧带损伤的诊断价值。方法 :回顾性分析 2 5例经手术或关节镜证实的前、后交叉韧带损伤患者 ,MR检查采用SE、TSE矢状位、冠状位及横断位T1WI、T2 WI及STIR。结果 :2 5例交叉韧带损伤中 ,部分性撕裂 16例 ,完全性撕裂 9例。MRI诊断交叉韧带部分性撕裂和完全性撕裂的符合率分别为 87.5 %和 88.9%。结论 :MR能较准确地诊断膝关节交叉韧带损伤及其并发症 ,为临床制订治疗方案提供可靠依据。     

Shoulder impingement syndrome: MR findings in 53 shoulders

The shoulder impingement syndrome refers to a condition in which the supraspinatus tendon and subacromial bursa are chronically entrapped between the humeral head inferiorly and either the anterior acromion itself, spurs of the anterior acromion or acromioclavicular joint, or the coracoacromial ligament superiorly. As a result, the space for the bursa and tendon is reduced, and repeated trauma to these structures leads to bursitis and rotator cuff injury. Although pain and limitation of motion are common early findings, the diagnosis is often delayed until a complete tear of the rotator cuff has occurred. In an attempt to determine if MR can be used to depict the abnormalities associated with impingement syndrome (subacromial bursitis, supraspinatus tendinitis, and rotator cuff tear), we reviewed 107 MR scans of painful shoulders. Changes consistent with impingement syndrome were found in 53 patients (50%), 32 of whom underwent subsequent arthrography or surgery. MR was found capable of depicting several soft-tissue and bony abnormalities that have been clinically described in impingement syndrome. In regions of inflammation, we found that the supraspinatus tendon and/or the subacromial bursa were compressed by spurs (25 shoulders), capsular hypertrophy of the acromioclavicular joint (six shoulders), and/or low-lying acromion (14 shoulders). While T1-weighted MR imaging was highly sensitive to abnormalities of the supraspinatus tendon, tendinitis could be differentiated from a small tear of the supraspinatus tendon only with T2-weighted imaging. Large, full-thickness tears, especially if chronic, produced characteristic MR findings on both T1- and T2-weighted images. We conclude that MR can be used to detect several abnormalities associated with the shoulder impingement syndrome.     

Teres minor denervation on routine magnetic resonance imaging of the shoulder

Objective To try to define an association between clinical history and the finding of isolated teres minor denervation on routine magnetic resonance (MR) examination of the shoulder.Design A retrospective review of all shoulder MR examinations performed at our institution over a 2-year period (n=2,563)Patients All patients and MR examinations demonstrating isolated denervation of the teres minor muscle as determined by review of this subset of patients (n=61)Results A 3% incidence of isolated teres minor denervation was found. No patient had a clinical history concerning the classic quadrilateral space syndrome, and no patient had a structural lesion in the quadrilateral space.Conclusions Isolated teres minor denervation is not an uncommon finding on routine shoulder MR imaging and may be associated with pathology other than a structural lesion in and about the axillary neurovascular structures, such as rotator cuff injuries and traction injury on the axillary nerve sustained during a glenohumeral joint translational event.     

Lipoma arborescens; successfully treated by yttrium-90 radiosynovectomy

Although radiosynovectomy (RS) applications have been carried out for many years, clinical indications of this non-invasive procedure is thought to be limited probably due to the lack of information of clinicians. Clinicians' preferential indication for RS is the treatment-resistant synovitis of individual joints, i.e. despite systemic pharmacotherapy and intra-articular steroid injections. We present here a case of "lipoma arborescens" treated by yttrium-90, which is a rare intra-articular lesion characterized by villous proliferation of the synovial membrane and hyperplasia of subsynovial fat. The results of clinical, biochemical and hematological examinations, magnetic resonance (MR) imaging, arthroscopy and histological analysis have shown that the etiology was lipoma arborescens in a female patient, aged 36 having swelling and sometimes associating pain at her right knee for 4 years. We have applied to our patient's right knee RS with 185 MBq yttrium-90 colloid together with 40 mg of methylprednisolone acetate, although in our literature survey we have not met any similar case being treated with such indication. Even a year after the application, the patient has absolutely benefited from the treatment clinically, and this was also confirmed by comparative MR images (pre- and post-treatment). Consequently, we consider that Y-90 treatment might be applicable in suitable cases with lipoma arborescens.     

Spontaneous recurrent hemarthrosis of the knee joint in elderly patients with osteoarthritis: an infrequent presentation of synovial lipoma arborescens

Synovial lipoma arborescens (SLA) is a rare, benign, fat-containing synovial proliferative lesion that is typically known to affect the knee joint in adults, although it has also been described in other joints. SLA usually presents as a painless swelling and recurrent joint effusion, and the laboratory test results, including aspirated synovial fluid, are usually normal. We present here two cases of SLA of the knee, which presented as spontaneous recurrent hemarthroses in elderly patients with osteoarthritis (OA) with bloody aspirated synovial fluid. Magnetic resonance imaging (MRI) and arthroscopic synovectomy suggested the diagnosis of SLA; the histopathologic examination confirmed the diagnosis. One year later, both patients remain symptom-free and report no new episodes of hemarthrosis. We postulate that SLA should be included in the differential diagnosis of patients with recurrent joint effusions with hemarthrosis in elderly patients with OA. The clinical presentation, MRI findings, and treatment of SLA are described, and the entity is briefly reviewed.