Polyarticular lipoma arborescens with inflammatory synovitis

Concurrent arboreal lipoma and synovial chondromatosis in an osteoarthritic knee: Insights from a rare case study - A surgical case report

INTRODUCTION AND IMPORTANCE

Conditions mimicking tumors within the knee, such as arborescent lipoma and synovial chondromatosis, are generally benign yet closely linked to inflammatory or degenerative joint diseases. While each condition is commonly documented individually with osteoarthritis, their concurrent presentation within the same knee is extremely rare. This case report adheres to the SCARE 2023 guidelines (Sohrabi et al., 2023) and aims to shed light on the diagnostic and therapeutic challenges posed by the rare coexistence of these conditions, presenting unique management challenges.

CASE PRESENTATION

We detail the case of a 67-year-old woman who has been suffering from progressively worsening bilateral osteoarthritis for over five years, with significant impairment in her right knee. Symptoms included persistent pain unresponsive to standard treatments, reduced mobility, and recurrent swelling. A comprehensive diagnostic evaluation through clinical examination, radiography, and magnetic resonance imaging (MRI) suggested tricompartmental osteoarthritis complicated by suspected arborescent lipoma. Surgical exploration not only confirmed the presence of arborescent lipoma but also revealed synovial chondromatosis. Both conditions were validated during total knee arthroplasty via histopathological examination, and the patient demonstrated significant functional recovery 18 months postoperatively.

CLINICAL DISCUSSION

The simultaneous occurrence of arborescent lipoma and synovial chondromatosis within an osteoarthritic knee emphasizes the complex nature of diagnosing and managing advanced joint pathologies. This case highlights the critical need for thorough diagnostic processes to differentiate between multiple potential diagnoses and the vital role of surgical intervention in managing such intricate conditions effectively.

CONCLUSION

The rare coexistence of arborescent lipoma and synovial chondromatosis in an osteoarthritic knee underlines the complexities of diagnosing and managing joint diseases. It accentuates the necessity of an exhaustive diagnostic approach and demonstrates the efficacy of surgical management in achieving favorable outcomes. This case supports the need for maintaining a broad differential diagnosis and underscores the value of interdisciplinary collaboration in managing complex joint pathologies.

Synovial Lipomatosis: Histopathologic Features in a Series of Five Cases

Synovial lipomatosis is a controversial entity of uncommon intraarticular joint lesions. Most studies focused on radiological findings and surgical resection modalities. Pathologic findings were limited to case reports. Detailed descriptions of the histopathologic features are lacking. We aim to highlight the salient histopathologic features of synovial lipomatosis. We performed a retrospective review study over 15 years retrieving cases of synovial lipomatosis. We found 5 patients (age range: 8-78, average age: 50 years, male to female ratio: 4:1) demonstrating unilateral synovial lipomatosis out of 241 (2.0%) patients with knee joint lesions. Four patients had osteoarthritis. One patient was obese. The resected specimens showed synovial hyperplasia, surface fibrin, hemosiderin pigment, microcalcifications, lymphoplasmacytic infiltrates, lymphoid aggregates, stromal fibrotic, degenerative, and metaplastic alterations shared by other synovitis related changes. Consistent features included abundant adipocytic components, surface adipocytes, prominent large vessel vasculatures, plasma cells, and dense perivascular lymphocytic cuff-like infiltrates. One patient demonstrated superimposed sarcoid-type epithelioid granulomas. A distinct fibrous band separated the lesional tissue from the underlying normal fatty tissue. Synovial lipomatosis predominates in older males with degenerative joint conditions with a second peak in children and adolescents. Obesity is not a risk factor. Some histopathologic features help distinguish synovial lipomatosis from look-alike joint lesions. The findings may suggest an angiolipomatous hamartomatous growth or an exaggerated synovial reaction inducing florid subsynovial stromal proliferative, metaplastic, and degenerative changes. Regardless of its etiopathogenesis, pathologists have a role in confirming the diagnosis and ensuring a complete arthroscopic synovectomy by assessing the presence of the fibrous septa.

Pathology of intra-articular tumours and tumour-like lesions: pearls, pitfalls and rarities from a general surgical pathology practice

Intra-articular tumours are uncommonly encountered in routine practice and may present diagnostic challenges to pathologists. Challenges unique to this site include distinction from more common reactive synovial conditions, which are far more common; histologic variability; superimposed reactive changes; and often, lack of provided clinicoradiological context. This article reviews the pathology of the synovial tumours and tumour-like lesions, including diagnostic pearls, pitfalls and rare entities.

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.

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.

BILATERAL LOCALIZED PIGMENTED VILLONODULAR SYNOVITIS OF THE KNEE: CASE REPORT AND REVIEW

Objectives

Several cases of bilateral diffuse pigmented villonodular synovitis (PVNS) or tenosynovial giant cell tumor have been described in the literature. Nevertheless, some presentations are rare and differential diagnoses are necessary.

Methods

The purpose of this study was to perform a systematic review of the literature related to PVNS and to report a rare supra-patellar bilateral and focal presentation. We performed a systematic data review in the Pubmed Clinical Queries database using MeSH and keywords related to PVNS and tenosynovial giant cell tumor.

Results

Two cases of bilateral and local PVNS had been previously described, but neither was localized in the supra-patellar compartment. To our knowledge, this case report is the first to describe supra-patellar bilateral and localized PVNS of the knee. This case involves a 28 -year-old woman with bilateral localized PVNS of the supra-patellar recess of the knee. MRI showed a low-signal intensity nodule in T1- and T2-weighted images. These were associated with hemosiderin pigmentation.

Conclusion

The most important finding of the case reported is related to rarity and location. Histopathology analysis confirmed a rare case of hemosiderin pigmentation in the capsular nodule with internal non-pigmented villous content. Lipoma arborescens in the supra-patellar form must be ruled out as a differential diagnosis since it occurs in the same site. Level of Evidence IV; Case series.

Isolated peroneal tenosynovial lipoma arborescens: multimodality imaging features

Synovial lipoma arborescens is a rare and benign fatty proliferative lesion of the synovium that is most commonly seen within the suprapatellar pouch of the knee, but increasingly reported to involve tendon sheaths, including those of the ankle. We present the third known case of tenosynovial lipoma arborescens isolated to the peroneal tendon sheath without ankle joint involvement. To our knowledge, this is the first to report this entity utilizing a unique combination of radiographic, sonographic, and MR imaging, along with intraoperative and histologic correlation. Knowledge of this case is important when interpreting radiographic or sonographic images of this condition to raise the possibility of the rare entity of lipoma arborescens involving the peroneal tendon sheath.

Arthroscopic Synovectomy in Bilateral Lipoma Arborescens

Introduction:

Lipoma arborescens (LA) is an uncommon condition that consists of a villous lipomatous proliferation of the synovial membrane. Open synovectomy has been previously selected as a curative treatment option. In recent years, some authors have published good results with arthroscopic interventions. We describe a well-documented case of bilateral LA of the knees treated with staged arthroscopic synovectomy.

Case Report:

A 48-year-old North American woman without a history of trauma presented with recurrent effusions and mild pain in both knee joints for many years. Magnetic resonance imaging examinations confirmed the diagnosis of bilateral LA with multiple villous lipomatous synovial proliferations pattern. Degenerative changes of the medial meniscus were detected bilaterally. The patient underwent bilateral arthroscopic anterior synovectomy and partial medial meniscectomy of the knee with three portal techniques. Arthroscopic the knee joint contained a large number or finger-shaped synovial proliferations with yellowish good vascularized diffuse villous masses in the suprapatellar bursa and intercondylar fossa. The cartilage showed degenerative changes with Outerbridge Grade II to III, which was particularly severe in the femoropatellar compartment. Histopathological examination of the villous masses demonstrated papillary hypertrophy, slight hyperplasia, vascular hyperplasia with a slight degree of stromal fibrosis, and interstitial lymphoplasmacytic inflammation. The adipose cells were reduced in number in relation to a normal finding but had a normal aspect without any pathological changes. 25 months after the first operation, the patient reported pain relief with the preserved function. Magnetic resonance examination of both knee joints at the last follow-up showed no relapse of the disease. The Knee injury and Osteoarthritis Outcome Score improved on the right knee joint from 39.3 preoperatively to 85.1 at the last follow-up, and on the left knee joint from 54.2 preoperatively to 86.3 at the last follow-up.

Conclusion:

Arthroscopic anterior synovectomy is an efficient method of achieving good results in LA with multiple villous lipomatous synovial proliferations pattern.

Lipoma Arborescens: Review of an Uncommon Cause for Swelling of the Knee

Lipoma arborescens is a rare cause of chronic monoarticular arthritis, with only a few cases reported in the literature. It is most commonly seen in the knee, but cases in other joints such as the wrist, shoulder, and elbow have also been described. It is a benign condition, in which the subsynovial tissue is replaced diffusely by mature fat cells. We describe a case involving the knee and discuss the symptoms, diagnosis, and treatment.

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.

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.

Polyarticular lipoma arborescens--a clinical and aesthetical case

Lipoma arborescens is a benign tumor, but it may be a reactive process to other disorders, and its clinical, analytical, radiological and ultrasound presentation may be redundant to any synovial tumor. Despite the characteristic feature on magnetic resonance imaging (MRI), the correct differential diagnosis in atypical presentation, and the need for timely removal of the lesion to prevent joint damage, forces, ultimately, to invasive procedures. The clinical case reported here, fourth described in English language publications on the polyarticular form, also presented other specificities related to one of the swellings, in the knee. Because of its atypical location in the popliteal fossa, recurrent episodes of joint effusion, personal history of knee trauma, pulmonary tuberculosis, and family history of rheumatoid arthritis required particular attention. This process was hampered by the refusal of knee (and ankle) surgery by the patient. He accepted surgical removal of the swellings of the wrists, for aesthetical reasons, with pathologic confirmation of the diagnosis, and clinical success in that location. MRI of the knee showed the typical image of lipoma arborescens, but also other changes that compromise the prognosis.