Imaging of pigmented villonodular synovitis with emphasis on MR imaging

MRI in shoulder arthropathies: A short review

Arthropathies are a frequent cause of shoulder pain and comprise of a wide range of clinical entities that may pose a diagnostic challenge. Though history and clinical examination remain vital, imaging plays a pivotal role in accurate diagnosis. Magnetic resonance imaging (MRI) remains an invaluable tool for imaging evaluation of shoulder involvement by various arthropathies. With attention to characteristic imaging features, radiologist may be able to differentiate between various disease processes affecting the shoulder joint. In this article, we have provided a brief review of common and uncommon MRI manifestations of various arthropathies affecting the shoulder joint.

Limited usefulness of classic MR findings in the diagnosis of tenosynovial giant cell tumor

OBJECTIVE

To determine the frequency with which MRI of tenosynovial giant cell tumor demonstrates hemosiderin, visible intralesional fat signal, and proximity to synovial tissue.

MATERIAL AND METHODS

This is a retrospective study of 31 cases of tenosynovial giant cell tumors which had concomitant MRI. Images were examined for lesion size, morphology, origin, bone erosions, MRI signal characteristics, contrast enhancement, and blooming artifact, comparing prospective and retrospective reports. Histology was reviewed for the presence of hemosiderin and xanthoma cells.

RESULTS

Eight lesions were diffuse and 23 were localized nodules. Three lesions were located in subcutaneous tissue and 4 adjacent to tendons beyond the extent of their tendon sheath. All lesions exhibited areas of low T1- and T2-weighted signal. Blooming artifact on gradient echo imaging was present in 86% of diffuse and only 27% of nodular disease. There was interobserver variability of 40% in assessing blooming. Iron was visible on H&E or iron stain in 97% of cases. Fat signal intensity was seen in only 3% of cases, although xanthoma cells were present on in 48%. The correct diagnosis was included in the prospective radiology differential diagnosis in 86% of diffuse cases and 62% of nodular cases.

CONCLUSION

Blooming on GRE MRI has low sensitivity for nodular tenosynovial giant cell tumors and is not universal in diffuse tumors. There was high interobserver variability in assessment of blooming. Intralesional fat signal is not a useful sign and may occur adjacent to tendons which lack a tendon sheath and may occur in a subcutaneous location.

Pigmented villonodular synovitis of the hip joint: Three cases demonstrating characteristic MRI features

Pigmented villonodular synovitis is a rare benign proliferative disease of synovial membranes, causing villonodular synovial hyperplasia and hemosiderin deposition. Its intra-articular forms most commonly affect the knee and less commonly the hip. PVNS of the hip is most common in the second to fifth decades and presentation is typically with pain and occasionally joint dysfunction. We review the existing literature and demonstrate characteristic magnetic resonance imaging features of pigmented villonodular synovitis in the hip joint using three biopsy-proven cases, with the aims of increasing awareness and aiding diagnosis of this rare but potentially debilitating and progressive condition. Recognition of its clinical presentation, appropriate use of magnetic resonance imaging and identification of imaging characteristics are essential to guiding biopsy interpretation and treatment.

Efficacy of image-guided synovial biopsy

OBJECTIVE

A variety of benign and neoplastic lesions can affect the synovium, including pigmented villonodular synovitis (PVNS) and synovial chondromatosis. Prior to surgical resection, accurate characterization of synovial lesions is necessary for appropriate treatment planning. Additionally, recent advances in potential medical therapies for PVNS could decrease or eliminate the need for surgery in some cases. Such treatment options demand accurate characterization of synovial lesions prior to treatment.

METHODS AND MATERIALS

Institutional IRB approval was obtained. We identified 54 synovial biopsies performed at our institution using a comprehensive database search under ultrasound (US) or computed tomography (CT) guidance. Cases were reviewed for pre-procedure imaging, location, biopsy approach, biopsy results, post-procedure complications, and surgical pathology if synovectomy was performed.

RESULT

A total of 54 image-guided synovial biopsies were performed, 36 using CT guidance and 18 using US guidance. Six different anatomic locations were biopsied (the hip, knee, shoulder, elbow, ankle, and temporomandibular joint). Synovial tissue was obtained in 89% of cases (48/54). CT-guided biopsies had a positive yield of 86% (31/36) and US-guided biopsies had a positive yield of 94% (17/18). Surgical pathology was obtained in 30 of the cases and image-guided biopsy concordance was 90% (27/30). Of the patients taken for synovectomy, biopsy concordance of suspected neoplastic lesions was 100% (23/23). In cases of suspected neoplasm, the concordance between image-guided biopsy and surgical pathology was 96% (22/23). There were no reported complications.

CONCLUSION

Image-guided biopsy of synovial lesions is safe and effective for establishing a definitive diagnosis prior to surgical or other intervention.

Diagnostic Imaging and Management of Common Intra-articular and Peri-articular Soft Tissue Tumors and Tumorlike Conditions of the Knee

Intra-articular (IA) and peri-articular (PA) tumors of the knee are frequently encountered by orthopaedic surgeons. Nonetheless, due to the possibility of great morbidity and potential mortality, it is important to recognize and differentiate between benign and malignant lesions in a timely manner. Therefore, the purpose of this article is to provide a concise, practical, and updated review of commonly encountered IA and PA tumors including intratendinous gout, synovial chondromatosis, schwannoma, pigmented villonodular synovitis, and synovial sarcoma, and a detailed description of differentiating features to include various imaging modalities.

Tenosynovial giant cell tumor of the cervical spine: a case report

Introduction

Tenosynovial giant cell tumors (TSGCTs) generally occur in the limb joints, and only rarely in the spine. This case report describes a patient with TSGCT of the spine at C1-C2, which was treated surgically and diagnosed as TSGCT.

Case presentation

A 32-year-old woman with a 4-month history of neck pain and numbness in both upper extremities was referred to our department. Magnetic resonance imaging (MRI) revealed a neoplastic lesion extending from the left epidural space to the erector spinae muscles at the C1-C2 vertebral level, which was isointense on T1-weighted images, heterogeneously hypointense on T2-weighted images, and showed heterogeneous enhancement on gadopentetate dimeglumine (Gd-DTPA)-enhanced T1-weighted images. Computed tomography showed no findings suggestive of bone destruction of the vertebral body. Because the neurological symptoms were progressive, total macroscopic resection of the tumor was performed via a posterior approach. Histopathological examination of the resected specimen revealed the diagnosis of TSGCT. Improvement of the both the neck pain and upper-extremity numbness was noted postoperatively. An MRI obtained 6 months after the surgery revealed no evidence of tumor recurrence and the postoperative course was uneventful.

Discussion

TSGCT of the upper cervical spine (C1-C2) is rare, and this is the tenth reported case. If a tumor is heterogeneously hypointense on T2-weighted MRI, which reflects hemosiderosis, the possibility of this tumor should be considered in the differential diagnosis.

Lowering the recurrence rate in pigmented villonodular synovitis: A series of 120 resections

Objectives

Tenosynovial giant-cell tumour or pigmented villonodular synovitis is an aggressive synovial proliferative disease, with the knee joint being the most commonly affected joint. The mainstay of therapy is surgical resection. The aim of this study was to evaluate the main patient characteristics, treatment and outcomes in a large single-centre retrospective study, focusing on meticulous aggressive open surgical procedures.

Methods

From 1996 through 2014, 122 surgical interventions were performed in 105 patients. All patients underwent open synovectomy and when the knee joint was affected, combined anterior and posterior synovectomy. Radiotherapy was applied in 2 patients, radiosynoviorthesis in 27 patients.

Results

In histopathology, the diffuse type was seen in 66 (54%) lesions. Two patients were lost during follow-up. At a median follow-up time of 71 months (range: 13-238), 22 (18%) lesions recurred within a median of 18 months, >90% in the first 3 years. Out of those 22 recurrences, 9 (11%) were seen in primary disease and 13 (34%) were a second recurrence. After renewed resection, 6 (5%) out of the 120 resections had persistent tumour at the end of follow-up. Based on the number of patients with complete follow-up (n = 103), this represents 5.8%.

Conclusion

In diffuse-type pigmented villonodular synovitis, total synovectomy might be difficult to achieve. As shown in our results and also in the literature, meticulous open resection, especially in difficult to approach areas such as the popliteal space, reduces local recurrence rates. External beam radiation is an option in prevention of otherwise non-operable local recurrences or in non-operable disease.

Tenosynovial giant cell tumors in unusual locations detected by positron emission tomography imaging confused with malignant tumors: report of two cases

Background

A tenosynovial giant cell tumor (T-GCT) is a benign synovial tumor arising from the synovium, bursae, or tendon sheath. It can be intra- or extra-articular and localized or diffuse. Diffuse T-GCT is considered as a locally aggressive. Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose with computed tomography (FDG PET/CT) is widely used to differentiate malignant from benign tumors and to detect distant metastasis. However, FDG PET/CT is limited by false-positive findings. In this study, we present two cases of T-GCT that developed in unusual locations and were confused with malignant tumors. The final diagnoses were histologically confirmed as T-GCTs.

Case presentation

Case 1. A 45-year-old Japanese female presented with a left choroidal melanoma and an abnormal lesion adjacent to the first cervical (C1) lamina confirmed by a PET scan (maximum standardized uptake value [SUVmax] = 9.9 g/ml). MRI of the neck also detected a soft tissue mass (14.6 × 7.7 × 7 mm) adjacent to the C1 lamina. The choroidal melanoma was treated by heavy carbon ion radiotherapy. Although the size of the C1 soft tissue tumor remained unchanged, a CT-guided biopsy confirmed the diagnosis of the neck mass as a T-GCT.

Case 2. A 15-year-old Japanese male with multiple type 1 neurofibromatosis presented with a soft tissue mass (26.1 × 24.7 × 11.5 mm) of the extra-articular hip joint that was coincidentally detected by FDG PET/CT during examination of a mediastinal soft tissue mass. SUVmax of the mediastinal lesion was 2.6 g/ml and of the hip lesion was 12.8 g/ml. Thus, differentiation from a malignant tumor, such as a malignant peripheral nerve sheath tumor, was necessary. An open biopsy was performed, and the frozen section was diagnosed as T-GCT. The tumor was excised, and the final histological diagnosis confirmed T-GCT.

Conclusion

T-GCT can show high FDG uptake, which might be confused with malignancy. Although MRI findings and location might help in the diagnosis of a T-GCT, careful assessment is mandatory, especially in unusual locations.

Benign soft-tissue lesions of the fingers: radiopathological correlation and clinical considerations

Soft-tissue lesions of the fingers are commonly found in daily clinical practice. A wide range of tumors and pseudotumors have been described in this location, and the majority of them are benign. Ganglion cysts are the most common entity, and the localized type of tenosynovial giant cell tumors are the most frequent solid condition. Both may be easily recognized owing to their typical clinical and radiological characteristics. However, categorization of the spectrum of soft-tissue lesions of the fingers remains limited, despite imaging development, and many patients undergo surgery before radiological or histological diagnosis. Clinical history, radiographic features, and ultrasound and magnetic resonance patterns may help in obtaining the correct diagnosis or reducing the list of differential diagnoses. Radiologists should be familiar with imaging findings so that they can determine the size, extension, and affected neighboring anatomical structures, and provide information that allows adequate presurgical counseling.

Pigmented villonodular synovitis of the temporomandibular joint with intracranial extension: A case series and systematic review

BACKGROUND

Pigmented villonodular synovitis (PVNS) is a rare proliferative disorder of the synovial membrane. PVNS generally affects large joints but occasionally involves the temporomandibular joint (TMJ), with occasional extension into the middle cranial fossa. The purpose of this study was to report our experience with PVNS along with a focused literature review.

METHODS

Patients with PVNS of the TMJ treated at the University of California - San Francisco from 2007 to 2013 were reviewed. A PubMed search was performed to identify additional cases.

RESULTS

Five patients underwent surgical resection, with 1 recurrence at 61 months. A literature review identified 58 patients, 19 of which had intracranial involvement. Interestingly, intracranial extension was more common in men. Intracranial extension was not associated with an increased rate of recurrence.

CONCLUSION

PVNS of the TMJ is a rare entity associated with excellent outcomes, even with intracranial extension. Management should consist of maximal resection, with radiotherapy reserved for extensive or recurrent lesions.

Localized form of pigmented villonodular synovitis of the knee: the meniscal mime

The localized form of pigmented villonodular synovitis of the knee is a rare condition with non-specific symptoms. This makes diagnosis especially difficult when the meniscus is affected. A full assessment with several imaging modalities can help support the preoperative diagnosis. But in the case reported here, the full clinical and paraclinical assessment (X-rays, CT arthrography and MRI) was wrong--the localized form of pigmented villonodular synovitis had mimicked a lateral meniscus injury and was only detected during arthroscopy. The lesion was excised surgically and the diagnosis was confirmed through postoperative histopathology.

Pigmented villonodular synovitis of the temporomandibular joint: CT imaging findings

OBJECTIVE

The purpose of this study was to determine the characteristic computed tomography (CT) findings of pigmented villonodular synovitis (PVNS) of the temporomandibular joint (TMJ).

STUDY DESIGN

Eight subjects with PVNS were examined with both pre and post contrast CT scans. All lesions were histopathologically confirmed through surgery. CT appearances of the lesions were reviewed.

RESULTS

Among the eight subjects, 8 (100%) demonstrated soft tissue mass and enhancement after contrast administration, 6 (75%) appeared as all or focal areas of noncontrast hyperdensity, 6 (75%) had widening of the joint spaces. Bony erosion of the mandibular condyles and articular surfaces were found in 7 (87.5%) and 6 (75%) subjects, respectively.

CONCLUSIONS

Based on the CT findings, PVNS of the TMJ is characterized by hyperdensity soft tissue mass and further increase in density after contrast administration, bony destruction of the mandibular condyles and skull base, and intracranial extension.

Tumors and diseases of the joint

A variety of different diseases affect the synovium, including infection, noninfectious immunologic inflammatory conditions, degenerative arthroses, crystal deposits, trauma, and tumors. Tumors of the synovium are relatively uncommon. Any mesenchymal tumor may arise in the synovium, but most recapitulate its normal counterpart including synoviocytes, blood vessels, fat, and fibrous tissue. These tumors can arise in any synovial lined structures both within joints and in extraarticular locations. Most synovial tumors are benign. Malignant tumors are rare but important to recognize because many are aggressive and must be treated appropriately. Among common nonneoplastic conditions that affect the synovium and surrounding structures are crystal deposits such as monosodium urate crystals, calcium pyrophosphate dihydrate crystals, and hydroxyapatite crystals. These crystal deposits may be asymptomatic or cause severe pain or chronic joint destruction. Their accurate identification is important to guide appropriate therapy.

Giant cell tumor of the pes anserine bursa (extra-articular pigmented villonodular bursitis): a case report and review of the literature

Pigmented villonodular synovitis (PVNS) is a rare, benign, proliferating disease affecting the synovium of joints, bursae, and tendon sheaths. Involvement of bursa (PVNB, pigmented villonodular bursitis) is the least common, and only few cases of exclusively extra-articular PVNB of the pes anserinus bursa have been reported so far. We report a case of extra-articular pes anserine PVNB along with a review of the literature. The lesion presented as a painful soft tissue mass in the medial part of the proximal leg. A magnetic resonance imaging showed areas of low to intermediate signals in all sequences and the lesion enhanced heterogeneously with contrast. Diagnosis was confirmed by an incisional biopsy, and an intralesional resection was performed. The postoperative course was uneventful, and the patient is free of disease with no functional deficit at 2 years followup. As with other rare lesions, clinical and radiographic findings in addition to histological examination are essential for correct diagnosis.

Soft-tissue tumors and tumorlike lesions: a systematic imaging approach

Soft-tissue lesions are frequently encountered by radiologists in everyday clinical practice. Characterization of these soft-tissue lesions remains problematic, despite advances in imaging. By systematically using clinical history, lesion location, mineralization on radiographs, and signal intensity characteristics on magnetic resonance images, one can (a) determine the diagnosis for the subset of determinate lesions that have characteristic clinical and imaging features and (b) narrow the differential diagnosis for lesions that demonstrate indeterminate characteristics. If a lesion cannot be characterized as a benign entity, the lesion should be reported as indeterminate, and the patient should undergo biopsy to exclude malignancy.

Subacromial bony erosion: a rare presentation of pigmented villonodular synovitis of the shoulder

Pigmented villonodular synovitis (PVNS) rarely affects the shoulder. We describe two cases of PVNS arising from the shoulder joint, which caused rotator cuff tears and sub-acromial bony erosion, and which were treated arthroscopically. Sub-acromial erosion is frequently associated with various glenohumeral joint disorders, but it has not been reported in association with PVNS. We believe PVNS should also be considered in the differential diagnosis of patients who present with sub-acromial erosion.

Pigmented villonodular synovitis: radiologic-pathologic correlation

Pigmented villonodular synovitis (PVNS) represents an uncommon benign neoplastic process that may involve the synovium of the joint diffusely or focally (PVNS) or that may occur extraarticularly in a bursa (pigmented villonodular bursitis [PVNB]) or tendon sheath (pigmented villonodular tenosynovitis [PVNTS]). Pathologic specimens of the hypertrophic synovium may appear villous, nodular, or villonodular, and hemosiderin deposition, often prominent, is seen in most cases. The knee, followed by the hip, is the most common location for PVNS or PVNB, whereas PVNTS occurs most often in the hand and foot. PVNTS is also referred to as giant cell tumor of the tendon sheath (GCTTS). PVNTS is the most common form of this disease by a ratio of approximately 3:1. Radiographs reveal nonspecific features of a joint effusion in PVNS, a focal soft-tissue mass in PVNB or PVNTS, or a normal appearance. Extrinsic erosion of bone (on both sides of the joint) may also be seen and is most frequent with intraarticular involvement of the hip (>90% of cases). Cross-sectional imaging reveals diffuse involvement of the synovium (PVNS), an intimate relationship to the tendon (PVTNS), or a typical bursal location (PVNB), findings that suggest the diagnosis. However, the magnetic resonance (MR) imaging findings of prominent low signal intensity (seen with T2-weighting) and "blooming" artifact from the hemosiderin (seen with gradient-echo sequences) are nearly pathognomonic of this diagnosis. In addition, MR imaging is optimal for evaluating lesion extent. This information is crucial to guide treatment and to achieve complete surgical resection. Recurrence is more common with diffuse intraarticular disease and is difficult to distinguish, both pathologically and radiologically, from the rare complication of malignant PVNS. Recognizing the appearances of the various types of PVNS, which reflect their pathologic characteristics, improves radiologic assessment and is important for optimal patient management.

Giant-cell tumour of the synovium in a facet joint in the thoracic spine of a child

Giant-cell tumour of the synovium is known to affect the fingers or toes of adults. It has seldom been described in the spine and rarely in the thoracic vertebrae or in a child. The lesions of giant-cell tumour of the synovium have a classical radiological appearance, but require a high index of suspicion for correct recognition. Unlike giant-cell tumour of the synovium at other well-known sites, spinal lesions lack the characteristic papillary architecture, thereby raising other diagnostic possibilities. We describe a giant-cell tumour of the synovium of the left facet joint of a thoracic vertebra in a nine-year-old girl. The tumour was treated successfully by surgical excision.

Pigmented villonodular bursitis/diffuse giant cell tumor of the pes anserine bursa: a report of two cases and review of literature

Pigmented villonodular synovitis (PVNS) is a benign but potentially aggressive lesion, characterized by synovial villonodular proliferation with hemosiderin pigmentation and stromal infiltration of histiocytes and giant cells. This consists of a common family of lesions, including localized and diffuse forms of pigmented villonodular synovitis, giant cell tumor of the tendon sheath (nodular tenosynovitis) and the very rare cases of extra-articular pigmented villonodular synovitis arising from the bursa (pigmented villonodular bursitis or diffuse giant cell tumor of the tendon sheath). The purpose of this paper is to present two rare cases of pigmented villonodular bursitis arising from the pes anserinus bursa. The various differentials along with a review of literature of similar lesions are also being discussed. However, as with other lesions, clinicoradiographic features along with close histological correlation is essential for diagnosis.

Two incision synovectomy and radiation treatment for diffuse pigmented villonodular synovitis of the knee with extra-articular component

Diffuse pigmented villonodular synovitis (PVNS) of the knee is a rare, locally aggressive disease. Since 1995 the senior author has been treating patients with diffuse intra- and extra-articular PVNS of the knee with a bimodality treatment protocol, consisting of anterior and posterior open synovectomies in conjunction with external-beam radiation. The purpose of this study was to describe the surgical technique, evaluate our protocol's efficacy in limiting local recurrences, and assess its functional implications and associated morbidities. The medical records of nine consecutive patients were analyzed. Functional results were measured using the Knee Society score. The mean follow-up was 67 months (range 37-103 months). Eight patients were disease free and one patient had local recurrence, which was extra-articular, localized and non-progressive. The mean knee rating and functional rating had significantly improved from 65.2 and 70 preoperatively to 93.7 and 96.6 postoperatively respectively. Maximal knee flexion ranged from 90 degrees to 130 degrees, and only 3 patients developed flexion contractures of 5 degrees. In conclusion our bimodality protocol of anterior and posterior open synovectomies, in conjunction with external-beam radiation, limited the recurrence of diffuse intra- and extra-articular PVNS of the knee. All patients showed good-to-excellent functional outcomes and were able to return to their previous level of activity.

MR Imaging: Arthropathies and Infectious Conditions of the Elbow, Wrist, and Hand

The superior soft tissue contrast and multiplanar capability of MR imaging has contributed to earlier diagnosis and implementation of effective treatment for a variety of arthropathies and infectious conditions of the elbow, wrist, and hand. Because of overlapping clinical signs and symptoms, MR imaging plays an important role in delineating the features and staging of each of these conditions. This article discusses the seropositive and seronegative inflammatory arthropathies, with emphasis on early detection and surveillance, as well as gout, synovial osteochondromatosis, pigmented villonodular synovitis, tenosynovitis, and de Quervain's tenosynovitis. Certain noninflammatory arthritides and infectious conditions are also reviewed.

Multifocal PVNS in a child--followed over 25 years

Pigmented villonodular synovitis (PVNS) is a rare disorder of unknown aetiology, characterised by a destructive fibrohistiocytic proliferation with production of villous and nodular protrusions. The disease is commonly monoarticular, and involves the knee in 80% of cases. Occurrence in a child and involvement of multiple joints are extremely unusual. We present a case of multiple joint PVNS in a patient who first presented at the age of five and was subsequently followed up for over twenty-five years. The literature on the subject is briefly reviewed.

Computed tomography and magnetic resonance imaging of unusual causes of ankle pain

Computed tomography and MRI are frequently utilized to evaluate ankle pain that remains unexplained by radiography. The most common causes of ankle pain are related to trauma and the imaging appearances of these entities are well established in the radiologic and orthopedic literature. A smaller percentage is comprised of non-traumatic disorders. Our goal is to emphasize the value of CT and MRI in recognition of these less common and unusual causes of ankle pain.

[Synovial lesions around the knee joint]

This article reviews the anatomy of synovial-lined structures around the knee joint including the joint capsule, plicae, bursae, and tendon sheaths. Pathologic conditions are grouped into either inflammatory, induced by deposition of various substances, or neoplastic. The MRI appearances of the various diseases are discussed.

[Pigmented villonodular synovitis of the knee joint]

Pigmented villonodular synovitis is a rare proliferative disorder of the synovial membrane most frequently found in the knee. The etiopathology of the disease is still not understood. Present terminology differentiates between a localized (LPVNS) and a diffuse (DPVNS) form. Currently, MRI is the diagnostic imaging technique of choice. The localized form (LPVNS) can be cured definitely in almost all cases by partial arthroscopic synovectomy, whereas the treatment of the diffuse form (DPVNS) is discussed controversially concerning an arthroscopic or total synovectomy by open arthrotomy. We report a case rarely found in the literature of a patient suffering from a diffuse form of PVNS localized in the right knee joint. In this case PVNS acted as a locally aggressive and destructive lesion of immense extent invading femoral, tibial and fibular bone and the whole extending muscular system. We performed a radical synovectomy by open arthrotomy. By implanting a tumor prosthesis we prevented progression of the disease. Apart from adequate diagnosis, we recommend complete and aggressive resection of the affected tissue by performing an open arthrotomy.

Imaging the ankle and foot and using magnetic resonance imaging

Magnetic resonance (MR) imaging has improved the possibility of evaluating musculoskeletal structures thus gaining an important role in the diagnosis and treatment of foot and ankle pathologies. In this review, the normal and pathological images of the ankle and foot obtained using MR techniques are presented and discussed. The high soft-tissue contrast resolution and the multiplanar sections of MRI allow the imaging of contiguous tissues where small contrast differences exist, such as ligamentous and tendinous injuries or impingement syndromes. The spatial resolution with high sensitivity for bone signal changes offers an early detection of osseous abnormalities such as stress fractures or osteonecrosis. Here it is specified possibilities and limitations of MRI in the diabetic foot: this technique is superior to nuclear medicine and computed tomography (CT), however it is unable to distinguish between neuro arthropathy and infection.

Localized pigmented villonodular synovitis in the anteromedial compartment of the knee associated with cartilage lesions of the medial femoral condyle: report of a case and review of the literature

Localized pigmented villonodular synovitis (PVNS) of the knee is an uncommon entity, presenting with different clinical signs and symptoms. We report on a case of a 42-year-old woman who presented with a 3-year history of knee pain and mechanical problems such as locking. On examination she was found to have a palpable and painful mass over the anteromedial joint line. Magnetic resonance imaging (MRI) revealed a soft tissue mass in the anteromedial compartment of the knee joint. The lesion was completely resected arthroscopically, and histologic examination confirmed the diagnosis of localized PVNS. The patient was free of symptoms, and MRI examination showed no evidence of recurrence at 1-year follow-up.

Pigmented villonodular synovitis of the temporomandibular joint: MR findings in four cases

OBJECTIVE

Although it is a rare condition, pigmented villonodular synovitis (PVNS) may involve temporomandibular joint (TMJ). The purpose of this study was to describe magnetic resonance (MR) findings of PVNS of the TMJ.

METHODS AND MATERIAL

Between April 1992 and August 2000, four patients (two men and two women, 22-58-year-old) who had histologically proven diagnoses of PVNS in their TMJ were found in our institution. Their MR findings were reviewed retrospectively, and were correlated with pathologic findings.

RESULTS

In all four patients, MR images invariably showed profound hypointensity on both T1- and T2-weighted sequences. This finding was seen diffusely and homogeneously throughout the lesion, and was considered to be due to paramagnetic effect attributed to heavy hemosiderin pigmentation, which was revealed by histopathological examination. MR images also showed aggressive nature of the lesions with adjacent skull base destruction and intracranial extension in two of them.

CONCLUSION

As is the case in the other anatomic site, PVNS of the TMJ can be confidently diagnosed on MR imaging on the basis of the presence of hemosiderin. MR imaging also plays a pivotal role in surgical planning by precise and detailed localization of the lesion.

Pigmented villonodular synovitis: an uncommon presentation of anterior hip pain

Pigmented villonodular synovitis (PVNS) is a rare, benign, idiopathic proliferative disorder of the synovium that results in villous or nodular formation in joints, tendon sheaths, and bursae. The disease can be localized or diffuse. Its estimated prevalence is 1.8 cases per million in the United States. Large joints, such as the knee and hip, are commonly affected. Patients with this condition typically present with symptoms of mild discomfort and associated stiffness of the involved joint; however, the spectrum of presentations is broad. We present a case of an otherwise healthy 40-yr-old man who presented for evaluation of stiffness and pain in the anterior hip. His initial presentation, work-up, and course will be discussed, along with a brief review of the literature.

Pigmented villonodular synovitis of the proximal tibiofibular joint

Pigmented villonodular synovitis is an uncommon proliferative disease of the synovium, which is usually monoarticular, presenting as chronic monoarthritis of the knee. To our knowledge, the case under discussion is only the second report in the English language medical literature of isolated involvement of the proximal tibiofibular joint.

MRI of Hoffa's fat pad

The infrapatellar fat pad of Hoffa is commonly injured but rarely discussed in the radiological literature. Abnormalities within it most commonly are the consequences of trauma and degeneration, but inflammatory and neoplastic diseases of the synovium can be confined to the fat pad. The commonest traumatic lesions follow arthroscopy, but intrinsic signal abnormalities can also be due to posterior and superior impingements syndromes and following patellar dislocation. Infrapatellar plica syndrome may also be traumatic in aetiology. The precise aetiology of ganglion cysts is not understood; the principal differential diagnosis is a meniscal or cruciate cyst. Hoffa's fat pad contains residual synovial tissue, meaning that primary neoplastic conditions of synovium may originate and be confined to the fat pad. Inflammatory changes along the posterior border of the pad may also be used to help differentiate effusion from acute synovitis on unenhanced MR examinations.

MR imaging: arthropathies and infectious conditions of the elbow, wrist, and hand

The superior soft tissue contrast and multiplanar capability of MR imaging has contributed to earlier diagnosis and implementation of effective treatment for a variety of arthropathies and infectious conditions of the elbow, wrist, and hand. Because of overlapping clinical signs and symptoms, MR imaging plays an important role in delineating the features and staging of each of these conditions. This article discusses the seropositive and seronegative inflammatory arthropathies, with emphasis on early detection and surveillance, as well as gout, synovial osteochondromatosis, pigmented villonodular synovitis, tenosynovitis, and de Quervain's tenosynovitis. Certain noninflammatory arthritides and infectious conditions are also reviewed.

MR imaging features of pigmented villonodular synovitis of the cervical spine

Pigmented villonodular synovitis (PVNS) is a benign proliferative disorder primarily occurring in the large joints of the appendicular skeleton such as the knee and hip joints. We present an unusual case of PVNS involving the cervical spine in an adult. MR imaging showed an enhancing mass lesion arising from the posterior elements of the cervical spine and hyperintensity on the T2-weighted images, without evidence of T2 susceptibility effects. Gross total excision of the tumor was performed, and the diagnosis was established by histopathology.

Cysts, geodes, and erosions

Subchondral cystic lesions are common features that are associated with many arthropathies and synovial-based processes. Although not comprehensive in scope, this article correlated the pathophysiology and imaging features of several of these disorders to better understand the associated subchondral lucencies. The imaging features of these subchondral cystic lesions were described in each process, and, in some cases, demonstrated overlapping features. By becoming familiar with the disease processes and recognizing the imaging appearances and associated clinical findings, the radiologist will be better able to differentiate these benign entities from more aggressive processes, such as tumor. Subchondral cystic lesions are common features that are associated with many arthropathies and synovial-based processes. Although not comprehensive in scope, this article correlated the pathophysiology and imaging features of several of these disorders to better understand the associated subchondral lucencies. The imaging features of these subchondral cystic lesions were described in each process, and, in some cases, demonstrated overlapping features. By becoming familiar with the disease processes and recognizing the imaging appearances and associated clinical findings, the radiologist will be better able to differentiate these benign entities from more aggressive processes, such as tumor.

Monoarticular arthritis

This article described many of the causes of monoarticular arthritis that are encountered in clinical practice. Although radiologists have relied on conventional radiography and bone scintigraphy, additional imaging methods have been introduced, such as MR imaging, CT scanning, and US. These methods improve visualization of intra-articular and periarticular soft tissue structures and are helpful in the guidance of arthrocentesis, drainage procedures, or percutaneous biopsies. Imaging findings always should be correlated with clinical abnormalities, and, when appropriate, joint fluid analysis.

MRI features of tuberculosis of peripheral joints

The aim of this article is to present the magnetic resonance imaging (MRI) features of peripheral tubercular arthritis. The clinical presentation of peripheral tubercular arthritis is variable and simulates other chronic inflammatory arthritic disorders. MRI is a highly sensitive technique which demonstrates fine anatomical details and identifies the early changes of arthritis, which are not visible on radiographs. The MRI features of tubercular arthritis include synovitis, effusion, central and peripheral erosions, active and chronic pannus, abscess, bone chips and hypo-intense synovium. These imaging features in an appropriate clinical setting may help in the diagnosis of tubercular arthritis. Early diagnosis and treatment can effectively eliminate the long-term morbidity of joints affected by tuberculosis.

Pigmented Villonodular Synovitis and Giant Cell Tumor of the Tendon Sheath

The purpose of this report was to determine the pattern of thallium (T1-201) uptake in pigmented villonodular synovitis (PVNS) and giant cell tumor of the tendon sheath (GCTTS) and to evaluate for features that might help to distinguish these lesions from malignant disease. Scintigraphic images from patients subsequently found to have pigmented villonodular synovitis confirmed by histopathologic analysis were assessed. The patients had been evaluated with T1-201 scintigraphy for a suspicious musculoskeletal lesion. All 6 patients with PVNS had significant T1-201 uptake on the early images with retention on the delayed images. The T1-201 activity was in a juxta-articular location and generally conformed to the synovial cavity with scattered irregular nodular components. Of 4 cases of giant cell tumor of the tendon sheath, all had T1-201 uptake on the early images, and 3 cases (75%) also had uptake on the delayed images. T1-201 uptake is observed almost invariably in pigmented villonodular synovitis on both early and delayed images and can simulate the findings of malignant disease. Features that should raise suspicion of PVNS include close proximity to a joint, especially with distribution corresponding to that of the synovial cavity. When T1-201 activity is detected in a lesion in the hand or foot, giant cell tumor of the tendon sheath should be considered. Magnetic resonance imaging will often aid in the differentiation by demonstrating features of hemosiderin degradation products.

Localized pigmented villonodular synovitis attached to the posterior cruciate ligament of the knee

Localized pigmented villonodular synovitis (PVNS) of the knee joint is a rare pathological entity characterized by a limited involvement of the synovium. We report on a case of localized PVNS which was attached to the posterior cruciate ligament and presented pain without mechanical symptoms. The lesion did not reach dimensions sufficient to interfere with joint function. After arthroscopic removal of the tumor, the patient has maintained asymptomatic status during the 2 year follow-up period.

MR imaging of sports-related hip disorders

Hip arthroscopy is being used increasingly for the diagnosis and treatment of hip disorders. MR imaging performed with appropriate technical considerations may aid not only in preoperative planning but in the appropriate selection of patients, which tends to lead to better postoperative results. Although the painful hip is imaged most commonly by radiography, MR imaging is considered the next imaging test of choice for evaluation of most common hip abnormalities in athletes, including labral injuries, ligament injuries, osteochondral injuries, fractures, bursitis, and musculotendinous injuries. MR arthrography can be a particularly useful technique for dedicated assessment of hip joint internal derangements.

Localized pigmented villonodular synovitis in an unusual location in the knee

PURPOSE

Localized pigmented villonodular synovitis (LPVNS) is a rare lesion that can affect any joint, although it is most frequently found in the knee. Clinically, it is difficult to diagnose. Radiographs are usually within normal limits.

TYPE OF STUDY

Case series.

METHODS

We present a series of 9 cases of LPVNS of the knee in 9 patients with an average age of 36 years. In 7 of the 9 cases, the lesions were in an an unusual location, 4 in the fat pad and 3 in the posterior compartment of the knee. The other 2 cases were located in the meniscocapsular junction and the intercondylar notch, respectively. The mean time from the onset of symptoms to diagnosis was 2.26 years. Magnetic resonance image (MRI) provided a characteristic image that helped with diagnosis and localizing the lesion in all cases.

RESULTS

Complete resection of the lesion using arthrotomy was performed in 4 cases and resection assisted using arthroscopy was performed in 5. All cases had an excellent result. There were no signs of clinical or MRI recurrence after a mean follow-up of 36 months.

CONCLUSIONS

LPVNS of the knee is a rare lesion. MRI provides the basis for diagnosis. Complete resection using arthrotomy or arthroscopy is the treatment.