Chondrosarcomas of the synovium

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.

Intracranial Metastasis of Extracranial Chondrosarcoma: Systematic Review With Illustrative Case

BACKGROUND

Cerebral chondrosarcoma metastases are rare and aggressive neoplasms. The rarity of presentation has precluded rigorous analysis of diagnosis, risk factors, treatment, and survival. We analyzed every reported case through exhaustive literature review. We further present the first case with Maffucci syndrome.

METHODS

Three databases, PubMed, Embase, and Google Scholar, and crossed references were queried for cerebral chondrosarcoma metastases. Extracted variables included demographics, risk factors, tumor characteristics, interventions, and outcomes. Univariate and multivariate analyses were performed.

RESULTS

Fifty-six patients were included from 1,489 literature results. The average age at brain metastasis was 46.6±17.6 years and occurred at a median of 24±2.8 months from primary diagnosis. Primary tumor histology (dedifferentiated 5.0±1.5 months, mesenchymal 24±3.0 months, conventional 41±7.4 months, p<0.05) and grade (low grade 54±16.7 months vs. high-grade 10±6.4 months, p<0.001) correlated with time interval until brain metastasis. A multiple enchondromatosis syndrome occurred in 13.2% of cases. At time of brain metastases diagnosis, extracranial metastases were identified in 76.2% of cases. Median survival after the development of brain metastasis was 2.0±0.78 months with a 1-year survival of 10.0%. On regression analysis, surgery reduced brain metastasis mortality risk and radiation trended towards reduced mortality risk (surgery: hazard ratio [HR] 0.22, 95% confidence interval [CI] 0.064-0.763, p=0.017; radiation: HR 0.31, 95% CI 0.091-1.072, p=0.064).

CONCLUSION

We present a systematic review of cerebral chondrosarcoma metastases. Primary tumor histology and grade correlate with time until cerebral metastasis. Following cerebral metastasis, these tumors have poor prognosis and modestly benefit from surgery.

Intra-Articular Tumors

The intra-articular space is a relatively rare site of occurrence of neoplastic diseases. The 2 distinct groups of clinicopathologic entities that exhibit an almost exclusive tropism for the joints are represented by synovial chondromatosis and tenosynovial giant cell tumors (TGCT). Synovial chondromatosis is a locally aggressive chondrogenic neoplasm that very rarely can show malignant behavior. TGCT occur in 2 main variants, the localized variant and the more locally aggressive diffuse type. Malignant TCGT is exceedingly rare and is characterized by significant rates of both local recurrence and metastatic spread.

Synovial chondrosarcoma: a single-institution experience with molecular investigations and review of the literature

AIMS

To evaluate the available diagnostic histological criteria for synovial chondrosarcoma and to screen for the presence of IDH1/IDH2 mutations in a series of cases of this malignant cartilaginous neoplasm.

METHODS AND RESULTS

Ten cases of synovial chondrosarcoma diagnosed at our institute were reviewed. At presentation, all tumours occurred in adults (median age, 62 years). The most common location was the knee joint (five cases), and the size at diagnosis ranged from 30 mm to 170 mm. Eight patients had secondary synovial chondrosarcomas associated with pre-existing/recurrent or concomitant synovial chondromatosis. Five patients had local recurrences and three had lung metastases. All patients with intralesional excisions developed local recurrences, whereas those who underwent wide resections did not. At last follow-up (mean, 91 months), available for nine patients, seven patients were alive and disease-free, one patient had died of disease, and one was alive with paravertebral metastases. Frequent histological features observed included loss of clustering of chondrocytes (nine cases), the presence of variable amounts of myxoid matrix (eight cases), peripheral hypercellularity (eight cases), tumour necrosis (six cases), and spindling of chondrocytes (four cases). Of the seven cases for which it was possible to evaluate bone permeation, six showed infiltration of bone marrow. All seven cases screened for mutations of exon 4 of IDH1 and IDH2 were found to be wild-type.

CONCLUSIONS

Histological criteria in correlation with clinical and radiological features allow the recognition of synovial chondrosarcoma. IDH1/IDH2 mutations were not present in synovial chondrosarcoma. Adequate surgical margins are important for disease control.

Extra-articular synovial chondromatosis of the ankle: Unusual case with radiologic-pathologic correlation

Extra-articular synovial chondromatosis is a rare entity in the foot and ankle. We present a case of a 49-year-old female who presented for evaluation of a palpable concern following trauma; which was found to represent synovial chondromatosis. This case demonstrates the multimodality imaging findings, including ultrasound and MRI, with histopathologic correlation.

Soft Tissue Special Issue: Chondroid Neoplasms of the Skull

Clinically, radiologically, and pathologically, chondroid neoplasms of the skull can be diagnostically challenging due to overlapping features in each of these domains. Compounding the problem for the pathologist, there is also significant morphologic, immunophenotypic, and molecular genetic overlap between benign and malignant cartilaginous lesions, and the majority of these lesions are encountered quite rarely in routine surgical pathology practice. Each of these factors contribute to the diagnostic difficulty posed by these lesions, highlighting the importance of radiologic-pathologic correlation in the diagnosis. This review is intended to provide an update for surgical pathologists on some of the most commonly encountered chondroid neoplasms in the skull, and includes the following lesions: chondromyxoid fibroma, synovial chondromatosis, chondrosarcoma and variants, and chordoma and variants. For each of these lesions, the differential diagnosis and useful ancillary tests will be discussed in the context of a broad range of additional primary and secondary lesions.

Synovial chondromatosis and soft tissue chondroma: extraosseous cartilaginous tumor defined by FN1 gene rearrangement

A fusion between fibronectin 1 (FN1) and activin receptor 2A (ACVR2A) has been reported previously in isolated cases of the synovial chondromatosis. To analyze further and validate the findings, we performed FISH and demonstrated recurrent FN1-ACVR2A rearrangements in synovial chondromatosis (57%), and chondrosarcoma secondary to synovial chondromatosis (75%), showing that FN1 and/or AVCR2A gene rearrangements do not distinguish between benign and malignant synovial chondromatosis. RNA sequencing revealed the presence of the FN1-ACVR2A fusion in several cases that were negative by FISH suggesting that the true prevalence of this fusion is potentially higher than 57%. In soft tissue chondromas, FN1 alterations were detected by FISH in 50% of cases but no ACVR2A alterations were identified. RNA sequencing identified a fusion involving FN1 and fibroblast growth factor receptor 2 (FGFR2) in the case of soft tissue chondroma and FISH confirmed recurrent involvement of both FGFR1 and FGFR2. These fusions were present in a subset of soft tissue chondromas characterized by grungy calcification, a feature reminiscent of phosphaturic mesenchymal tumor. However, unlike the latter, fibroblast growth factor 23 (FGF23) mRNA expression was not elevated in soft tissue chondromas harboring the FN1-FGFR1 fusion. The mutual exclusivity of ACVR2A rearrangements observed in synovial chondromatosis and FGFR1/2 in soft tissue chondromas suggests these represent separate entities. There have been no reports of malignant soft tissue chondromas, therefore differentiating these lesions will potentially alter clinical management by allowing soft tissue chondromas to be managed more conservatively.

Malignant Transformation of Recurrent Synovial Chondromatosis: A Case Report and Review

Chondrosarcoma is the second most common primary malignant bone tumor. While the majority arrive de novo, a minority arise from malignant transformation of benign neoplasms, such as osteochondromas. Rarely, chondrosarcomas have been found to originate from other preexisting lesions, such as synovial chondromatosis. A 44-year-old male with a history of a spinal osteochondroma presented with one year of left hip pain and decreased range of motion. On examination, he had a palpable, irregular fullness in the left groin that was minimally tender to palpation. Radiographs and CT of the hip showed extensive soft tissue calcifications and erosion of the femoral neck. The lesion was debulked surgically and histologically diagnosed as synovial osteochondromatosis with no evidence of atypia or cellularity. One year later, his residual disease progressed and resulted in increasingly limited range of motion. He underwent left total hip arthroplasty with simultaneous debulking and the lesion was once again diagnosed as synovial osteochondromatosis. Two months postoperatively, the patient developed a new focus of calcification around the hip joint that was thought to be recurrent disease. Six months later, due to worsening symptoms, he underwent a repeat CT scan. This scan demonstrated extensive intra-articular disease extending into the iliopsoas bursa and around total hip arthroplasty, as well as a new soft tissue nodule with foci of calcification in the left gluteus maximus. The new lesion was debulked surgically and diagnosed as a grade 1 chondrosarcoma. Chondrosarcoma arising from synovial chondromatosis is a rare presentation of the second most common primary malignant bone tumor. It typically presents as an indolent, slowly growing painful mass of large joints in middle aged men. Conventional radiography shows punctate opacities, while MRI and CT reveal diffuse soft tissue calcification and cortical erosion. Low-grade chondrosarcomas are treated with intralesional curettage and adjuvant therapy, while higher grade chondrosarcomas are treated with wide, en bloc excision. Malignant transformation should be considered in any patient presenting with worsening symptoms and a history of a benign bony lesion.

Chondrosarcoma arising within synovial chondromatosis of the lumbar spine

Synovial chondromatosis is an uncommon benign neoplasm that usually affects large appendicular joints and only rarely the spine. There are only a few small series and case reports documenting malignant transformation of synovial chondromatosis into secondary chondrosarcoma, typically within the hip in the setting of recalcitrant disease and multiple recurrences. Chondrosarcoma arising in synovial chondromatosis of the spine is exceedingly rare, with only one previously published case report involving the craniocervical junction. We present a case of chondrosarcoma arising within synovial chondromatosis of the lumbosacral spine, with the diagnosis made at the time of initial presentation. We describe the clinical, imaging, and histopathological findings and review diagnostic criteria for this difficult diagnosis.

Chondrosarcoma of the jaw: a retrospective series

OBJECTIVES

Low-grade chondrosarcoma presents with features similar to those of benign lesions, such as chondroma and synovial chondromatosis, increasing the difficulty in reaching an accurate diagnosis preoperatively. In this study, we retrospectively reviewed 10 chondrosarcoma cases and evaluated the diagnostic approaches and management modalities.

STUDY DESIGN

Ten cases were included in the present study. We evaluated the clinical features, initial diagnosis, histopathology subtype, immunohistologic markers, final diagnosis, and treatment modalities.

RESULTS

Most of the lesions were found in the mandible. Two cases were followed up for 1 month and 4 years, respectively as benign lesions before malignant changes were detected. With regard to chondrosarcoma histopathology subtypes, 6 cases were identified as conventional chondrosarcoma, whereas 4 cases were diagnosed as mesenchymal chondrosarcoma with aggressive behavior; of these, 3 were associated with local recurrence and metastasis. The immunohistologic markers showed no specificity for chondrosarcoma.

CONCLUSIONS

Distinguishing low-grade chondrosarcoma, particularly in the temporomandibular joint, from benign lesions, such as chondroma or synovial chondromatosis, remains difficult. Currently, the correlation between clinical, radiographic, and histologic features accompanied by close follow-up is extremely important for patients diagnosed with chondrogenic lesions. Postoperative radiotherapy seems to be beneficial in patients with positive surgical margins.

Bone tumours around the elbow: a rare entity

Bone tumours around the elbow are rare. Even nowadays diagnostic dilemmas and delays are common. During recent decades the management and prognosis of patients with elbow bone tumours has improved significantly.Benign tumours can be treated using minimally invasive procedures, whereas malignant ones require a multidisciplinary team approach based on an adjuvant therapeutic regimen of chemotherapy, radiotherapy and limb salvage procedures.This article reviews the most commonly encountered elbow bone tumours and their management. Cite this article: EFORT Open Rev 2019;4:133-142. DOI: 10.1302/2058-5241.4.180086.

Synovial chondromatosis of the temporomandibular joint: Report and analysis of 12 cases

OBJECTIVE

We had for aim to study the clinical manifestations, diagnostic imaging techniques, histopathological and therapeutic findings of patients presenting with synovial chondromatosis (CS) of the temporomandibular joint (TMJ).

MATERIAL AND METHODS

We reviewed the clinical history of all our patients who were diagnosed with CS between 2009 and 2013.

RESULTS

We identified 12 cases of TMJ-CS, in 4 male and 8 female patients, with a mean aged of 50.5 years at diagnosis (range: 43-86 years). The average symptom duration prior to diagnosis was 11 months (range: 1-24 months). The most frequent clinical manifestations were joint pain (10 cases), restricted movement (6 cases), and swelling (4 cases). Panoramic radiographs were not contributive. CT scan and MRI findings led to a diagnosis in every case. 2 to 30 foreign bodies with various degrees of aggregation were removed by arthrotomy in our series and synovectomy was performed in all patients. These foreign bodies were in the upper compartment and the articular disk was not affected in 10 cases. A histopathological examination confirmed the diagnosis. The mean postoperative follow-up was 78 months. No case of chondrosarcoma was identified and the recurrence rate was low (1 case).

DISCUSSION

The clinical manifestations of TMJ-CS are common and conventional imaging is poorly contributive so that the diagnosis is often late. The delay before diagnosis was an average11 months for our patients given our experience; it was almost twice longer in other series. Arthrotomy and excision of the loose bodies led to confirmation by histopathological analysis. Most of the time, this treatment is sufficient but long term clinical and radiological monitoring is required.

Intra- and extracapsular synovial chondromatosis of the temporomandibular joint: Rare case and review of the literature

Synovial chondromatosis is a benign disease which most commonly appears in large joints and only rarely affects the temporomandibular joint. The diagnosis is quite difficult due to the fact that a large swelling in the preauricular area and the radiographic findings may be misdiagnosed as other benign or malignant diseases. We report an unusual case of intra- and extracapsular chondromatosis of 25 osteochondral loose bodies in the right temporomandibular joint.

Ulnar nerve palsy caused by synovial protrusion in synovial chondromatosis of the elbow: a case report and literature review

We describe an unusual case of ulnar nerve compression (cubital tunnel syndrome) caused by synovial protrusion in primary synovial chondromatosis of the elbow in a 59-year-old man. Magnetic resonance imaging is a useful tool for diagnosing this rare condition. Surgical excision of the intra-articular multiple loose bodies and ulnar nerve decompression were performed. The clinician should be aware of primary synovial chondromatosis as one of the causative factors of cubital tunnel syndrome.

Integrating Morphology and Genetics in the Diagnosis of Cartilage Tumors

Cartilage-forming tumors of bone are a heterogeneous group of tumors with different molecular mechanisms involved. Enchondromas are benign hyaline cartilage-forming tumors of medullary bone caused by mutations in IDH1 or IDH2. Osteochondromas are benign cartilage-capped bony projections at the surface of bone. IDH mutations are also found in dedifferentiated and periosteal chondrosarcoma. A recurrent HEY1-NCOA2 fusion characterizes mesenchymal chondrosarcoma. Molecular changes are increasingly used to improve diagnostic accuracy in chondrosarcomas. Detection of IDH mutations or HEY1-NCOA2 fusions has already proved their immense value, especially on small biopsy specimens or in case of unusual presentation.

Malignant Transformation of Synovial Chondromatosis: A Systematic Review

Background:

Synovial chondromatosis (SCh) can undergo malignant transformation. Pathologic diagnosis of secondary synovial chondrosarcoma (SChS) is challenging and misdiagnosis may result in over- or undertreatment.

Method:

A systematic review revealed 48 cases of SChS published in 27 reports since 1957. Data was collected to identify findings indicative of SChS and outcomes of treatment.

Results:

At median follow-up of 18 months, patients were reported as alive (10%), alive without disease (22%), alive with disease (15%), dead of disease (19%), dead of pulmonary embolism (4%), and unknown (29%). Initial diagnosis of SChS (grade: low/unknown 48%, intermediate/high 52%) was after biopsy in 58%, local resection in 29%, and amputation in 13%. Seventy-four percent of patients underwent 1.8 (mean) resections. Patients treated prior to 1992 were managed with amputation in 79% of cases compared to 48% after 1992. Symptoms were present for 72 mos prior to diagnosis of SChS.

Synovial chondrosarcoma demonstrated symptom progression over several months (82%), rapid recurrence after complete resection (30%), and medullary canal invasion (43%). The SChS tumor dimensions were seldom quantified.

Conclusion:

Malignant degeneration of synovial chondromatosis is rare but can necessitate morbid surgery or result in death. Pathognomonic signs for SChS including intramedullary infiltration are present in the minority of cases. Progression of symptoms, quick local recurrence, and muscle infiltration are more suggestive of SChS. Periarticular cortical erosion, extra-capsular extension, and metaplastic chondroid features are non-specific. Although poorly documented for SChS, tumor size is a strong indicator of malignancy.

Biopsy and partial resection are prone to diagnostic error. Surgical decisions are frequently based on size and clinical appearance and may be in conflict with pathologic diagnosis.

Primary synovial chondromatosis of the talonavicular joint: A case report

Synovial chondromatosis developes by metaplasia of the synovial cells in the synovium of joints, and is a benign synovial tumor with multiple cartilaginous nodules. It is most commonly found in single and large joints, such as the knee, hip, and shoulder. Occurrence in the foot and ankle is uncommon, although there have been previous reports in the orthopedic and radiological literature of primary synovial chondromatosis in the subtalr, calcaneocuboid, naviculocuneiform, and metatarsaophalangeal joints. To our knowledge, occurrence in the talonavicular joint is even rarer, with only one report in the literature to date. Here, we report a case of synovial chondromatosis of the talonavicular joint, alongside a review of the literature.

Synovial chondrosarcoma

BACKGROUND

Synovial chondrosarcoma (SCH) is a very rare tumor arising in the intra-articular cavity. In the majority of literature reports it is described as a malignant transformation of a pre-existing synovial chondromatosis (SC). We reported a systematic review of primary and secondary SCH described in the literature with the aim to recollect data from different case-reports and case-series, trying to summarize general aspects of this very rare disease.

METHODS

We collected 42 abstracts in the form of case series and case reports, which reported 67 cases of SCH. Studies were taken into account only if they proved a histological diagnosis of SCH, either primary or secondary, with or without evidence of pre-existing SC.

RESULTS

The average age of SCH was 56.9 years, with prevalence for male sex. The average time of malignant transformation was 11.2 years. The most affected joint was the knee (47.7%), followed by hip (34.3%) and ankle (5.9%). SCH was described as de novo sarcoma only in 13 cases (19%). Surgery ended up with amputation in 59.7% of cases. Local recurrence rate was 28.3%.

CONCLUSIONS

We concluded that prognosis of SCH is worse than conventional one and we speculated this is due to the difficult site of the tumor (intraarticular), diagnostic delay and inappropriate previous treatments. We consider that a rapid deterioration of a SC or rapid recurrence after synoviectomy should be considered suspicious of malignant transformation and should be treated in a reference center.

Extraarticular Synovial Chondromatosis: Review of Epidemiology, Imaging Studies, Microscopy and Pathogenesis, with a Report of an Additional Case in a Child

A rare benign condition of uncertain etiology and pathogenesis, Synovial Chondromatosis (SC) is most often seen intraarticularly in adults but only a handful of cases have been reported extraarticularly in children. Symptoms and physical signs consist of pain, swelling, and osteoarthritic changes related to a mass effect. Here we discuss the case of a 9-year-old boy with documented SC of the knee and critically review the Epidemiology, Clinical Presentation, Gross Anatomy and Microscopic Histopathologic Features as well as the role of Imaging Studies in Diagnosis. In addition, this paper reviews Current Pathogenetic Concepts including the infrequent but distinct possibility of malignant transformation.

Intracapsular Chondroma of the Knee: An Unusual Neoplasm

Intracapsular chondroma is a rare lesion that has been reported under different names on 23 occasions. We describe a 52-year-old woman with intracapsular chondroma that involved the left knee. Radiologically, the mass was multilobulated, calcified, and sharply circumscribed and was lying between the patella and the anterolateral surface of the tibia. The peculiar histologic pattern of the tumor was composed of hyaline cartilage nodules with enchondral ossification or calcification, in apparent transition with septa of connective and adipose tissue. The most common differential diagnoses for this tumor are primary synovial chondromatosis and chondrosarcoma. We emphasize a possible metaplastic origin of the chondromatous component due to some mechanical posttraumatic disturbance of the infrapatellar fat pad. To our knowledge, the present case is the second intracapsular chondroma to be described in the European literature.

Primary synovial chondromatosis: a reassessment of malignant potential in 155 cases

OBJECTIVE

Primary synovial chondromatosis (PSC) is a rare disorder characterised by cartilage formation in synovium-lined joints, tendon sheaths and bursae. It is thought that PSC cartilage arises from the proliferation of mesenchymal cells, which exhibit cartilaginous metaplasia in subintimal connective tissue. There are reports of transformation of PSC to chondrosarcoma, although the precise incidence and nature of this complication is uncertain. In this study we carried out a retrospective review PSC to determine the incidence of sarcomatous change in this condition, in addition to the clinical, radiological and pathological features that characterise this complication

MATERIALS AND METHODS

We reviewed 155 cases of PSC and identified 4 cases (3 in the hip joint; 1 in the elbow joint) of aggressive behaviour and chondrosarcoma-like histology.

RESULTS

Radiologically, these cases were all reported as showing features consistent with PSC and aggressive extra-articular soft tissue/bone involvement. Histologically, in addition to typical features of PSC, there was morphological evidence of peri-articular soft tissue and, in 2 cases, bone involvement by an infiltrating cartilaginous tumour. These tumours all behaved as locally aggressive neoplasms and did not give rise to metastasis.

CONCLUSION

Our findings show that chondrosarcoma arises infrequently in PSC (approximately 2.5 %), and that this complication occurs most commonly in the hip joint (approximately 11 % of cases of hip PSC). These tumours behaved mainly as low-grade, locally aggressive tumours analogous to atypical cartilaginous tumour of bone/grade 1 chondrosarcoma of bone.

Primary intra-articular sarcoma: a clinicopathological study of 15 cases

AIMS

To assess the clinical and histopathological spectrum of primary intra-articular sarcomas.

METHODS AND RESULTS

Fifteen patients were identified as having primary intra-articular sarcomas and the clinical and pathological features were evaluated. There were nine males and six females who ranged in age from 16 to 84 (mean 44) years. All tumours originated in the knee joint. The pathological diagnoses included: five synovial sarcoma, three extraskeletal myxoid chondrosarcomas, two high-grade myxofibrosarcoma (one conventional, one epithelioid), two undifferentiated pleomorphic sarcoma (one with giant cells) and one each myxoinflammatory fibroblastic sarcoma, conventional hyaline chondrosarcoma, and high-grade myofibroblastic sarcoma. All tumours were treated by segmental resection or amputation. Adjuvant therapy was given in selected cases. Follow-up ranged from 11 to 150 months. Of patients with follow-up, two died of disease; one developed pulmonary metastases after 6 years and was then lost to follow-up. Nine patients were alive and free of disease 12-150 months after diagnosis.

CONCLUSIONS

Primary sarcomas of the joints are very rare and most frequently affect the knee. Our experience indicates that synovial sarcoma and extraskeletal myxoid chondrosarcoma are the most common intra-articular sarcomas.

Imaging features of synovial chondromatosis of the spine: a review of 28 cases

OBJECTIVE

To describe the radiographic, CT, and MRI appearance of synovial chondromatosis of the spine.

MATERIALS AND METHODS

Radiology and pathology databases were searched for cases of spinal synovial chondromatosis from 1984 through 2013, yielding 29 patients (16 males, 13 females). The average age was 45 years. Twenty-eight patients had imaging studies available for review including seven radiographs, two myelograms, 13 CT, and 23 MRI exams.

RESULTS

Cases were located in the cervical spine (16), thoracic spine (6), lumbar spine (6), and sacrum (1). Twenty-two cases (79%) had an epidural component. Eighteen (64%) had a neural foraminal component. Sixteen (57%) had a paraspinal component. The mass abutted a facet joint in 96% of cases. Nearly all (96%) showed a normal facet joint without internal erosive changes. Most (79%) showed evidence of chronic extrinsic bony erosion, usually involving the surface of the facet. Only 44% had calcifications as a dominant finding. Most patients (88%) had evidence of neural compression. On T1-weighted MRI, 80% showed intermediate or a combination of intermediate and dark signal. On T2-weighted images, 89% showed heterogeneous signal with discrete areas of dark signal. The majority (83%) showed a peripheral pattern of enhancement, usually peripheral nodular.

CONCLUSIONS

Synovial chondromatosis should be considered in the differential diagnosis when evaluating an epidural and/or paraspinal mass near a facet joint, especially when there is evidence of chronic extrinsic bone erosion, dark signal or nodules on T1 and/or T2, and nonenhancing fluid or myxoid signal centrally with thin or nodular peripheral enhancement.

[Synovial tumors and tumor-like lesions]

Synovial tumors comprise a variety of lesions, including those with benign and aggressive neoplastic changes as well as inflammatory causes. In this article we focus on neoplastic tumors. Synovial tumors with other etiologies, such as sarcoidosis, granuloma, synovitis, or gouty arthritis, are not dealt with here. Through a precise differentiation between these disease entities can an optimization of treatment be achieved.

Synovial Chondromatosis of the Temporomandibular Joint Successfully Treated by Surgery

Synovial chondromatosis (SC) is a chronic process, defined as a reactive cartilaginous proliferation, characterized by formation of cartilaginous nodules, usually loose in the joint space of the synovial membrane. It mainly affects large joints such as knee, hip, shoulder, and elbow, commonly in male patients. However, its manifestation in the Temporomandibular joint (TMJ), is a rare finding, occurring predominantly in females. This paper reports a case of a woman who presented to the service of Stomatology complaining of mouth opening limitations and pain in her left pre-auricular region. After clinical and radiographic analyses, the condition was diagnosed as SC of the TMJ. The loose bodies within the TMJ were removed under general anesthesia. Histological and follow-up features of this lesion are also discussed. To our knowledge, this is the second report of SC of the TMJ in Brazil.

Odyssey of an elbow synovial chondromatosis

Synovial chondromatosis of the elbow is an uncommon condition. However, a chondrosarcoma arising from the former is remarkably rare. The authors report a case of an elbow chondrosarcoma secondary to synovial chondromatosis in a 38-year-old woman. Before the development of chondrosarcoma, the patient underwent 3 operations and 3 sessions of radiosynovectomy because of continuous recurrence of synovial chondromatosis on the left elbow. After the last radiosynovectomy, magnetic resonance imaging and biopsy showed a grade II chondrosarcoma secondary to synovial chondromatosis. The patient underwent further surgery and custom-made arthroplasty because of aseptic loosening of the prosthesis. Four months after the last intervention, 3 subcutaneous nodes appeared on the patient's elbow and were histologically found to be a recurrence of chondrosarcoma (grade III). Amputation by disarticulation of the shoulder was performed in addition to biopsy of another subcutaneous node on the abdomen. The biopsy showed metastasis of chondrosarcoma. At final follow-up, the patient had lung metastasis 7 years after the initial diagnosis. A reason for the manifestation of primary synovial chondromatosis and its progression to chondrosarcoma has not been found. Synovial chondromatosis progressing to chondrosarcoma in the elbow was reported in only 1 case, with no clear initial diagnosis. The role of radiosynovectomy in the development of chondrosarcoma is unknown, and no reports have described the treatment of elbow synovial chondromatosis. Although synovial chondromatosis is benign, its metaplastic nature is a marker of possible malignancy, especially with signs of recurrence and aggression. The role of radiosynovectomy in malignant changes should be examined in future studies.

Synovial chondromatosis of pes anserine bursa secondary to osteochondroma

Osteochondromas are common benign bone tumors. Synovial chondromatosis is a benign cartilaginous metaplasia that occurs in the synovium. The authors describe a unique case of synovial chondromatosis developing in the pes anserine bursa secondary to an underlying osteochondroma of the proximal medial tibia. It is unusual to see both of these processes occurring simultaneously in 1 location. After appropriate consent was obtained, the patient's case was reviewed. A 17-year-old boy presented with a painless mass in the medial aspect of the right leg. Initial imaging of the right leg showed a cartilaginous-appearing lesion arising from the tibia and several distinct additional cartilaginous masses in the adjacent soft tissue. After 16 months of observation, the patient began to have increasing pain in the region of the lesion. The patient underwent surgery for excision of suspected synovial chondromatosis of the right pes anserine bursa and osteochondroma of the proximal right tibia. Postoperatively, the patient had complete resolution of symptoms and regained full range of motion of the knee. He returned to full activities, including walking and running. Osteochondromas are common benign bone tumors. Synovial chondromatosis is a benign synovial metaplastic cartilaginous proliferation that occurs primarily in joints, but can occur in any synovial-lined space. In this case report, the authors describe a unique occurrence of both of these lesions simultaneously. The treatment was excision of the osteochondroma and resection of the chondromatosis lesions, which resulted in an excellent outcome.

[Secondary chondrosarcoma: radiopathological correlation]

Chondrosarcomas are malignant bone tumors originating in cartilage. Chondrosarcoma is the third most common malignant bone tumor after multiple myeloma and osteosarcoma. About 75% of chondrosarcomas are primary lesions. The remaining 25% belong to special categories such as histologic variants and secondary forms. A secondary chondrosarcoma is one that appears in a pre-existing benign chondral lesion; the different types of secondary chondrosarcomas include solitary osteochondroma, multiple osteochondromatosis, enchondroma, the different types of enchondromatosis, and primary synovial chondromatosis. The incidence of this malignant transformation varies widely in function of the type of lesion. In this article, we discuss and illustrate the different types of secondary chondrosarcomas, placing special emphasis on the imaging findings that should alert to these lesions and give radiologists a key role in the diagnosis, management, and follow-up of these patients.

Synovial chondrosarcoma arising in synovial chondromatosis

Primary synovial chondromatosis (SC) is a rare proliferative disorder that causes pain, swelling, and restriction of movement to the joints it affects. The disease frequently runs a protracted course, often requiring multiple surgical procedures to obtain some control. Few reports exist detailing the natural history of SC, although malignant transformation to synovial chondrosarcoma (CHS) is recognized to be a rare event. The aim of our study was to review a large orthopaedic oncology database in order to evaluate the incidence of CHS arising from SC. We identified 78 patients who have presented to our centre with primary synovial chondromatosis (SC). Of those patients, 5 went on to develop malignant change. This represents a 6.4% incidence of developing synovial chondrosarcoma (CHS) within preexisting primary synovial chondromatosis. The patients had a mean age of 28 years at first diagnosis with synovial chondromatosis with the median time from original diagnosis to malignant transformation being 20 years (range 2.7-39 yrs).

Synovial chondromatosis of the temporomandibular joint: clinical, cytologic, histologic, radiologic, therapeutic aspects, and differential diagnosis of an uncommon lesion

Synovial chondromatosis (SC) of the temporomandibular joint (TMJ) is a rare disorder with an indolent clinical course that leads to nonspecific symptoms, dysfunction, and anatomic distortion of the TMJ. We describe a case of SC in an 82-year-old male that presented as an incidental 2 cm cystic tumor of the left TMJ, during diagnostic work-up for unrelated symptoms. A fine needle aspiration of the lesion yielded fragments of abnormal mature cartilage and myxoid fluid. The diagnosis of SC was suggested after correlating the clinical and pathologic findings. Open TMJ surgery was performed for definitive diagnosis and therapy. This manuscript describes the clinical, radiologic, cytologic, and pathologic features of this entity, and relates the differential diagnosis to other cartilaginous lesions and neoplasms of the TMJ. Awareness of this disorder is important to provide adequate care and avoid overtreatment.

Synovial chondrosarcoma arising in synovial chondromatosis of the temporomandibular joint

Synovial chondromatosis of the temporomandibular joint is rare. Even less commonly documented is the progression of synovial chondromatosis to a synovial chondrosarcoma. The aim of this paper is to present only the third case of synovial chondrosarcoma of the temporomandibular joint. Distinction between these two entities by histology alone is extremely difficult and even though it is advised that the definitive diagnosis should be based on clinical, radiographic and histological evidence, this has proved not to be so simple. The patient, a 63 year old female presented with a swelling associated with her left temporomandibular joint. CT and MRI scans confirmed the presence of a periauricular chondroid mass. Fine needle aspiration biopsy revealed an atypical chondroid lesion that was supicious for a chondrosarcoma. The left temporomandibular joint and surrounding tissues were resected after further imaging and extensive clinical, radiological and cytologic consultations. A diagnosis of synovial chondrosarcoma arising in synovial chondromatosis was made.

Synovial Osteochondromatosis With Malignant Transformation to Chondrosarcoma in a Dog

A 4.5-year-old intact male Labrador Retriever dog had a 1-month history of right forelimb lameness with painful swelling of the elbow. The radiographic findings of increased synovial mass with mineralized opacities and the gross and histologic findings in the synovial biopsy specimens were consistent with a diagnosis of primary (idiopathic) synovial osteochondromatosis. Twenty months after initial presentation, based on progression of clinical signs and radiographic evidence of marked bone lysis in the distal aspect of the humerus and proximal aspects of the radius and ulna, the affected leg was amputated. The histologic diagnosis was chondrosarcoma with fibroblastic differentiation and bone lysis. The chondrosarcoma was interpreted as malignant transformation of primary synovial osteochondromatosis.

Primary synovial chondrosarcoma of the hip joint in a 45-year-old male: case report and literature review

Synovial chondrosarcoma is a rare tumor, seen most commonly arising from antecedent synovial chondromatosis, the more common benign entity. The distinction between the two can be difficult on the basis of clinical, imaging, and histologic criteria. The authors report a case of pathologically proven synovial chondrosarcoma of the hip in a 45-year-old male initially treated for presumed synovial chondromatosis. The case is made more unusual by the fact that no evidence of co-existent synovial chondromatosis was noted at histology. The literature as regards synovial chondrosarcoma, both de novo and secondary cases, is reviewed.

Giant solitary synovial chondromatosis of the temporomandibular joint with intracranial extension

Synovial chondromatosis are rare entities but are well-described lesions in the literature that can affect many joint areas of the body. A case of tumoral synovial chondromatosis involving the temporomandibular joint with intracranial extension through mandibular fossa is reported. As long as there was significant infratemporal and extradural invasion of the middle and posterior fossa, a transtemporal and infratemporal approach was performed and total removal of the lesions was achieved. A brief review of skull base synovial chondromatosis is presented.

Synovial chondromatosis and chondrosarcoma: a diagnostic dilemma

Purpose: The progression of synovial chondromatosis to chondrosarcoma is very rare. Distinction between these two entities may be difficult on histology alone, and should be based on clinical, radiographic and microscopic evidence. Immunohistochemical markers that would facilitate differentiation between synovial chondromatosis and chondrosarcoma are currently being investigated.

Patients: We describe the cases of two patients who presented with synovial chondromatosis and progression to synovial chondrosarcoma during periods of 7 and 11 years. Several biopsies and resected specimens demonstrated synovial chondromatosis before a diagnosis of chondrosarcoma was made.

Method: We have examined five markers (Bcl2, Ki67, p27, p16, and p53) in all specimens from these cases, as well as known cases of chondromatosis and chondrosarcoma for control purposes.

Results: We found increased expression of Bcl2 in benign chondromatosis compared to synovial or central chondrosarcomas.

Discussion: Distinction between chondromatosis and its progression to low grade chondrosarcoma is difficult at histological level, and must involve incorporation of clinical and radiographical data. Although preliminary, our study suggests that reduced or absent expression of Bcl2 is associated withmalignant transformation of chondromatosis.

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.

The management of solitary tumours of Hoffa's fat pad

Hoffa's fat pad (HFP) of the knee is affected by a variety of tumours and tumour-like conditions. HFP can be affected by diffuse or solitary, focal disease. This paper reports a consecutive series of 19 cases of solitary symptomatic HFP tumours. The commonest presenting symptom was anterior knee pain. All patients underwent open excision after diagnostic magnetic resonance imaging (MRI). Histology revealed varied diagnoses with the commonest being pigmented villonodular synovitis (PVNS) and ganglia. American Knee Society scores improved from 76 pre-operatively to 96 post-operatively with an improvement in functional scores from 92 to 100. In conclusion the majority of solitary HFP tumours are benign and may be either cystic or solid. MRI and plain radiographs are the imaging of choice. The definitive treatments of both cystic and solid tumours should be selective arthrotomy and excision biopsy. All patients in this series reported substantial improvement in symptoms following surgery.

Bilateral synovial chondromatosis of the temporomandibular joint

PURPOSE

To report an exceptional case of bilateral synovial chondromatosis (SC) of the temporomandibular joint (TMJ) and discuss diagnostic approaches, treatment options and follow-up data.

PATIENTS AND METHODS

A 38-year-old woman presented with left preauricular swelling. Initial imaging studies revealed TMJ effusion only. Six years later, synovial calcifications were detected in the left TMJ; the right TMJ space was widened and presented incipient calcium deposits. Open arthrotomy of the left TMJ was performed, with removal of multiple cartilaginous loose bodies and complete synovectomy. Periodic controls proved the asynchronic development of intra-articular bodies in the right TMJ.

RESULTS

SC is a metaplastic arthropathy that is uncommon in the TMJ. Bilaterality is exceptional. Diagnosis is often delayed due to the non-specific symptoms, progressive developmental stages and clinicians' lack of awareness of the condition. Magnetic resonance imaging (MRI) is particularly helpful in defining disease extension, excluding a possible tumour and detecting internal derangement. Definitive diagnosis requires arthroscopic or open examination and histopathological analysis. Recurrences are infrequent after arthrotomy, removal of loose bodies and complete synovectomy.

CONCLUSION

SC is an uncommon condition in the TMJ. Bilateral involvement is extremely rare. MRI is effective for diagnosis and postoperative follow-up. Complete synovectomy usually yields an excellent prognosis.

Recurrence of synovial chondromatosis of the Hoffa's body

Synovial chondromatosis of Hoffa's body is uncommon. Recurrences usually result from incomplete removal of the loose bodies or diseased synovium at the initial surgery. We report a patient with synovial chondromatosis localized into the Hoffa's body who presented with anterior knee pain and mechanical symptoms. At the first arthroscopy, all pathological tissue was removed. At 1-year follow-up, clinical and radiographic examinations were normal. Symptoms recurred at 3 years, when a bony mass in the Hoffa's body was evident on MRI. The mass was removed through a mini-arthrotomy. Histology excluded malignancy. At 10-year follow-up, the patient remained free of symptoms. Synovial chondromatosis can occur with unusual patterns of recurrence. The growth of a large size mass confined to fat pad without intra-articular involvement does not allow to exclude the diagnosis of recurrent synovial chondromatosis.

Two rare involvement sites: synovial chondromatosis

Synovial chondromatosis (SC) is a rarely encountered benign disease of unknown etiology characterized by multiple joint mouse, as well as metaplastic cartilage points in the joint, bursa and tendon sheaths. Although single joint involvement is frequently encountered, multiple joint involvements may also occur. In this study, two patients with SC in the right shoulder joint and in both ankles were presented, reviewed according to literature.

Myoepithelioma within the carpal tunnel: a case report and review of the literature

Myoepitheliomas of the extremity are rare and usually benign, while a minority display malignant features. This case demonstrates the diagnosis and management of myoepithelioma within the carpal tunnel. Clinical and radiological tumour features were evaluated. Hematoxylin and eosin stained tumour sections were examined, and immunohistochemistry was performed. Histology revealed a nodular mass of epithelioid cells in clusters within a myxoid/chondroid stroma. No mitoses were noted. Cytokeratins, neuron-specific enolase, synaptophysin, glial fibrillary acidic protein, and S100 were positive on immunohistochemistry. A literature review revealed very few prior reports of myoepithelioma in the wrist, and limited data concerning any relationship between recurrence and quality of surgical margins. In this case, wide local excision would have significantly compromised dominant hand function, and therefore a marginal excision was deemed appropriate in the context of bland histological features. Surgical margins noted in future case reports will aid clinical decision making.

[Synovial chondromatosis]

Primary articular synovial chondromatosis is a benign, self-limiting neoplastic process in which hyaline cartilage nodules form in the synovial tissue. The disease most frequently affects the knee in men, followed by the elbow. The basic feature of this disease is a metaplastic maturation of the mesenchymal cells in the synovial membrane of a joint into cartilage. These cells mature into chondroblasts and form small nodules of cartilage in the synovial membrane. These nodules subsequently enlarge and detach to lie within the joint space. They become free within the joint as multiple small cartilaginous loose bodies nourished by the synovial fluid. The chondrocytes in the loose bodies continue to multiply, and the loose bodies grow in diameter. Calcification appears in the central zone of the loose bodies, and in some cases, enchondral ossification takes place. The operative therapy depends on the stage of the disease: synovectomy with removal of chondral fragments if active intrasynovial disease is present, and removal of the multiple chondral bodies alone in cases of late inactive disease with no synovial abnormalities. Malignant transformation is unusual and can be difficult to distinguish from benign disease.

[Recurrent synovial chondromatosis of the tarsometatarsal joint. Case report and review of literature]

Primary synovial chondromatosis is a rare and usually monoarticular metaplasia of the synovia. It may recur, but the tendency to malignant transformation is very low. The radiological and histopathological differentiation from low grade chondrosarcoma can be difficult. We present a case report of a 32-year-old male with synovial chondromatosis in the tarsometatarsal joint area, which is an uncommon localization.