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

Lipoma Arborescens of the Upper Extremity With Anatomic Variation of the Palmaris Longus: A Case Report

CASE

We present a case of a patient who suffered from wrist swelling and had symptoms of carpal tunnel syndrome. The patient underwent ultrasound and magnetic resonance imaging, in which signs of joint effusion and a fatty synovial lesion were presented. The treatment included open excision of the tumor. In addition, the palmaris longus muscle had an anatomic variation with proximal and distal tendon portions. The histopathological examination disclosed lipoma arborescens of the synovial membranes of the joints.

CONCLUSION

The recognition of this entity and its characteristics are important not only for correct diagnosis but also for the appropriate treatment.

Surgical management of upper limb lipoma arborescens: a systematic review

Background

Lipoma arborescens (LA) is a rare benign synovial tumour characterized by the proliferation of mature adipocytes within the synovial cells. Given its rarity, current evidence is mainly based on case reports and case series, and no guidelines are available. The present study investigated the current surgical management and related outcomes of LA in the upper limb.

Methods

This systematic review was conducted following the PRISMA guidelines. PubMed, Scopus, and Virtual Health Library were accessed in September 2021. Clinical studies evaluating patients with LA undergoing surgical treatment were considered eligible for this systematic review. Only studies which reported data on LA located in the upper limb with histopathological confirmation were considered. Articles that reported data from nonsurgical management were not considered.

Results

A total of 21 studies reporting 22 lesions in 21 patients were assessed. The mean age of the patients was 48.48 years (range 22–77). Most studies evaluated the restoration of range of motion and symptom resolution for the functional outcome assessment. Open or arthroscopic excision and synovectomy were the most common surgical procedures for LA. The concomitant lesions were treated in a single-stage procedure. All patients had satisfactory outcomes after open or arthroscopic excision and synovectomy without recurrence at a mean follow-up of 21.14 months (range 2–60). One patient developed postoperative cellulitis (4.55%).

Conclusion

Open and arthroscopic excision combined with synovectomy should be considered the standard treatment option of upper limb LA. Concomitant pathologies can be addressed in a one-stage procedure. Although LA was recognized as a clinical entity decades ago, there is a lack of evidence based guidelines and long term outcome data are unavailable.

Imaging features of lipoma arborescens

BACKGROUND

Lipoma arborescens is characterized by the villous proliferation of the synovium and diffuse hyperplasia of fatty tissue in the subsynovial layer, almost always with a periarticular lesion. According to past articles, fewer cases have depicted the imaging features of lipoma arborescens.

PURPOSE

To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) features of lipoma arborescens.

MATERIAL AND METHODS

The imaging features of 15 patients with pathologically proven lipoma arborescens were retrospectively analyzed including lesion number, shape, location, size, margins, attenuation on CT, and signal intensity and enhancement patterns on MR images.

RESULTS

All cases (n=15) showed joint or bursa effusion. The primary lesion attached to the bursa wall adjacent to the bone in 13 cases and to the lateral wall in two cases. CT shows a mass with fatty tissue attenuation values in the suprapatellar pouch (n=3) or subdeltoid bursa with an erosion of the humeral head (n=2), among them two cases showed branched slightly high density in the center of the fat density tissue. Fifteen cases on routine MRI display mass-like subsynovial mass with fatty tissue signal on all of the sequences and suppression of the signal on fat-suppression sequences. Among them, five lesions showed branched slightly low T1-weighted imaging, high proton density-weighted imaging, and T2-weighted imaging signals in the center. It showed the enhancement of the linear surface and the bursa wall in contrast-enhanced MRI (n=3).

CONCLUSION

Lipoma arborescens have specific CT and MRI features that enable them to make a conclusive diagnosis of this rare condition, which helps the diagnosis before treatment.

Lipoma Arborescens of the Subdeltoid Bursa Associated With Rotator Cuff Tear: A Case Report

Lipoma arborescens is a rare synovial lesion characterized by villous proliferation of the synovial membrane and replacement of subsynovial tissue with mature fat cells. The knee joint is the most frequently affected site, particularly in the suprapatellar pouch. However, there have been few reports regarding shoulder involvement, including the glenohumeral joint and subacromial subdeltoid bursa, associated with rotator cuff tear. This article reviews the case of a 67-year-old man who presented with lipoma arborescens of the left shoulder, associated with a rotator cuff tear. Sonography revealed a fluid collection with thickening of the synovial membrane with hyperechoic villous proliferation, located in the subdeltoid bursa. An arthroscopic synovectomy and rotator cuff repair were performed. Arthroscopic findings included yellow frond-like synovial proliferation of the synovium. Postoperatively, the patient was asymptomatic, and the lesion did not recur. Although magnetic resonance imaging is the first-line imaging modality for diagnosis of this lesion, sonography may be used initially for evaluation of chronic joint swelling. In addition, it can be useful for detection of recurrence after synovectomy. This case illustrates the typical sonographic features of lipoma arborescens.

Lipoma arborescens - Uncommon Diagnosis for Joint Swelling: Case Report and Review of the Literature

INTRODUCTION

Soft tissue swelling of the knee joint can be caused by many diseases. Lipomas are one of the most reasonable differential diagnoses we have to consider. Therefore, we now present the uncommon case of a Lipoma arborescens (LA) and differentiate it from a quite similar manifesting spindle cell lipoma as follows.

CASE REPORT

A 49-years old patient reports about progressive knee pain for four years and observes an increasing joint swelling. This swelling is a soft tissue, shiftable tumour, not painful. The magnetic resonance imaging (MRI) with contrast agent brings the diagnosis of an advanced osteoarthritis of the knee joint and classifies the tumour as LA. Subsequently, we treat the osteoarthritis by implanting a total knee arthroplasty with simultaneous intraoperative tumour resection performed as total synovectomy. The histopathological processing confirms the clinically and radiologically made diagnosis of LA.

SUMMARY

Lipoma arborescens presents an uncommon subgroup of Lipomas, which is characterized by a slowly progressive increasing soft tissue swelling, especially around bigger human joints. Due to its intraarticular location, the LA might become clinically relevant when it reaches a certain tumour size. Looking at the diagnostics, sonography, MRI and especially the histopathological processing give the crucial results. Final proof can only be made by histopathological examination. Additionally, we have some differential diagnoses to exclude. Under these we predominantly find the spindle cell lipoma, synovial haemagioma, vascular synovial malformations and tenosynovial giant-cell tumour. Furthermore, an atypical lipomatous tumour should be excluded by FISH-analysis via determining the MDM2-Genamplification.

Synovial Lipomatosis of the Glenohumeral Joint

Synovial lipomatosis (also known as lipoma arborescens) is a rare and benign lesion affecting synovium-lined cavities. It is characterized by hyperplasia of mature fat tissue in the subsynovial layer. Although the most commonly affected site is the knee joint, rarely additional locations such as tendon sheath and other joints are involved. We present a case of synovial lipomatosis of the glenohumeral joint in a 44-year-old man. The clinical data radiological studies and histopathologic results are described, as well as a review of the current literature.

Lipoma arborescens associated with osseous/chondroid differentiation in subdeltoid bursa

Lipoma arborescens (LA) is a rare benign lesion of unknown etiology. It is characterized histologically by villous proliferation of the synovial membrane and diffuse replacement of the subsynovial tissue by mature fat cells. This condition affects the knee joint most commonly. Cases involving other locations including glenohumeral joint,[1] hip,[2] elbow,[3] hand[4] and ankle[5] have been rarely described. Involvement of the subdeltoid bursa has also been reported, but to date no case has described LA with osseous/chondroid differentiation of this bursa. Another significant finding in our case was the coexistence of LA with intermuscular lipoma, SLAP lesion and labral cyst.

Subdeltoid lipoma arborescens combined with rotator cuff tears

Lipoma arborescens, a rare benign intra-articular lesion, is characterized by lipomatous proliferation of the synovium in which the subsynovial tissue is replaced by mature adipocytes. Subdeltoid bursa is a rare location for lipoma arborescens, and only a few cases have been reported in the literature. This article reports 2 cases of subdeltoid lipoma arborescens combined with rotator cuff tears, and the possible relationships between subdeltoid lipoma arborescens and rotator cuff tears are discussed. The intra-articular villous proliferations on fat-suppressed T2-weighted magnetic resonance imaging appeared as yellowish-white lipomatous villous proliferations on arthroscopy, and finger-like lipomatous proliferation of the synovium, where the subsynovial connective tissue is replaced by mature adipocytes, on histology. Although further evidence would be necessary, the bony proliferations, in addition to bone-to-bone abrasion and inflammatory processes, may contribute to the relationship between subdeltoid lipoma arborescens and rotator cuff tears. Because this is a rare disease in a rare location, no established treatment guidelines are available for lipoma arborescens in subdeltoid bursa. For the current patients, arthroscopic excision of the lipoma arborescens and concomitant rotator cuff repair were prescribed after more than 6 months of conservative management. All patients had symptom relief and were satisfied with their results. Paying special attention to the radiologic and arthroscopic characteristics of the lipoma arborescens will help physicians and surgeons to achieve a more accurate diagnosis and effective treatment strategy, especially in patients with concomitant rotator cuff tears.

Lipoma arborescens: An unusual cause of swelling of the knee

We report a patient with a lipoma arborescens in the knee, a chance finding discovered on MRI. This is an unusual cause of swelling of the knee joint; if this condition is present, it is almost always located in the suprapatellar pouch. In this case, the lipoma arborescens was found in the popliteal space.

Light and electron microscopic features of synovium in patients with psoriatic arthritis

INTRODUCTION

Few ultrastructural studies have been reported in psoriatic arthritis (PsA). The authors report a series of synovial biopsies with emphasis on patients with early disease to look for distinctive light (LM) and electron microscopic (EM) features of possible importance.

METHODS

The authors examined synovial biopsies obtained primarily by needle biopsy from 13 PsA patients using LM and/or EM. Sections from 12 patients were evaluated by LM for vascularity, synovial lining thickness, fibrin deposition, and inflammation via a semi-quantitative scale. Nine EM specimens were descriptively analyzed. Clinical, synovial fluid (SF), and radiographic characteristics were recorded.

RESULTS

Patients were mostly male, with mean disease duration before biopsy of 2.19 ± 2.60 years; 7 patients had arthritis for less than 1 year. All patients had peripheral arthritis, 2 had axial involvement. SFs disclosed predominance of polymorphonuclear leukocytes. LM demonstrated proliferation of synovial lining cells, lymphocyte and plasma cell infiltration, as well as dramatic clusters of small vessels in the superficial synovium. EMs showed more detailed vascular changes, including small, subendothelial, electron-dense deposits and scattered microparticles in vessel lumens and walls.

CONCLUSIONS

Prominent vascularity is confirmed as an important feature of some PsA. Vascular changes and other features, including the first EM demonstration of microparticles in PsA (identified as potent factors in other inflammatory joint diseases), are potential targets for therapy.

Bilateral Knee Lipoma Arborescens Combined with Osteoarthritis in Elderly Patients

Here, three cases of combined lipoma arborescens (LA) — a rare neoplastic lesion of the synovium — and osteoarthritis (OA) with bilateral knee involvement in elderly patients are reported. The clinical, magnetic resonance imaging and histological characteristics of this rare condition are described. Limited by the similarity of symptoms between LA and OA and the low sensitivity of X-ray for discerning LA, it was found that a diagnosis of LA could be easily missed. Follow-up data suggested that the treatment of LA was not jeopardized even if the diagnosis was not made preoperatively, since the lesion is easily discerned intraoperatively. The definitive treatment of synovectomy can then be performed without recurrence of the lesion. Based on the evidence of the sequence of symptoms and the progression of untreated LA with static OA at follow up, it is suggested that the aetiology of LA is secondary to OA in elderly patients.

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.

A case of intra-articular synovial lipoma of the knee joint causing patellar dislocation

Intra-articular synovial lipoma is rare and clinically manifested mostly by mass effect and occasionally by torsion of the stalk. Patellar dislocation rarely occurs owing to a mass effect of intra-articular tumor of the knee joint. The authors present a case of large intra-articular synovial lipoma at the lateral gutter of the knee joint, which presents as patellar dislocation. A 19-year-old man visited our clinic due to pain and limitation of motion owing to mass at his left knee. MRI revealed an intra-articular soft tissue mass at the lateral gutter of the knee joint with considerable mass effect displacing patella from the trochlear groove. Excisional biopsy confirmed the diagnosis of lipoma, and the final diagnosis was intra-articular synovial lipoma with clinical information. The final radiograph showed well-aligned patella on the trochlear groove. After marginal excision, there was no recurrence or tumor-related morbidity.

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.

[Lipoma arborescens of the bicipital bursa]

Lipoma arborescens is a rare benign entity characterized by proliferation of villous fat tissue in subsynovial layer that usually affects the knee joint. We report a case of lipoma arborescens in bicipitoradial bursa of the elbow in a 44 year-old female patient. In spite of this rare location, radiographic findings by ultrasonography and magnetic resonance imaging made diagnosis possible.