Tophaceous pseudogout (tumoral calcium pyrophosphate dihydrate crystal deposition disease)

Pseudogout growing from the temporomandibular joint into the middle cranial fossa

Calcium pyrophosphate dihydrate deposition disease (CPDD or pseudogout) is a degenerative joint disease. It is defined by the presence of calcium pyrophosphate dihydrate crystals. It usually manifests in the knee and wrist. Manifestation in the temporomandibular joint (TMJ) is only reported in case reports. We present a patient with CPDD mimicking a malignant tumor of the TMJ. A 53-year-old woman presented with progressive pain and a slow-growing swelling of the left TMJ. Imaging showed an extensive mass in the infratemporal fossa extending into the middle cranial fossa and compressing the temporal lobe. Assuming a potential malignancy, we excised the growth, which extended into the dura. We covered the resulting tissue defect within the primary surgery using a microsurgically anastomosed scapular flap and performed further reconstructive surgeries. Calcium pyrophosphate dihydrate crystals were found in the histopathologic examination of the excised tissue, resulting in the diagnosis of CPDD. That is a benign diagnosis, but we treated it like a malignancy. This leads us to the question, was there overtreatment? Tumoral CPDD in the TMJ can be a difficult diagnosis to obtain. The treatment remains controversial, but complete excision of the mass was performed in most reported cases.

Calcified Chondroid Mesenchymal Neoplasms

Calcified chondroid mesenchymal neoplasms (CCMN) represent a morphologic spectrum of related tumors. Historically, chondroid matrix or chondroblastoma-like features have been described in soft tissue chondroma, tenosynovial giant cell tumors (especially of the temporomandibular joint (TMJ) region), and in a subset of tophaceous pseudogout. Recently, these tumors have been found to share FN1-receptor tyrosine kinase (RTK) fusions. This review discusses the clinical, morphologic, immunohistochemical, and molecular genetic features of CCMN. The distinction from morphologic mimics is also discussed.

Calcified Chondroid Mesenchymal Neoplasm: Exploring the Morphologic and Clinical Features of an Emergent Entity With a Series of 33 Cases

Calcified chondroid mesenchymal neoplasm is a term proposed for tumors with a spectrum of morphologic features, including cartilage/chondroid matrix formation, that frequently harbor FN1 gene fusions. We report a series of 33 cases of putative calcified chondroid mesenchymal neoplasms, mostly referred for expert consultation out of concern for malignancy. Patients included 17 males and 16 females, with a mean age of 51.3 years. Anatomic locations include the hands and fingers, feet and toes, head and neck, and temporomandibular joint; 1 patient presented with multifocal disease. Radiologic review showed soft tissue masses with variable internal calcification, which occasionally scalloped bone but in all cases appeared indolent/benign. Tumors had a mean gross size of 2.1 cm and a homogenous rubbery to fibrous/gritty tan-white cut surface. Histology demonstrated multinodular architecture with a prominent chondroid matrix and increased cellularity towards the periphery of the nodules. The tumor cells were polygonal with eccentric nuclei and bland cytologic features and showed a variable amount of increased spindled / fibroblastic forms in the perinodular septa. The majority of cases had notable grungy and/or lacy calcifications. A subset of cases demonstrated at least focal areas of increased cellularity and osteoclast-like giant cells. Herein, we confirm the distinct morphologic and clinicopathologic features associated with this entity with the largest series to date, with a focus on practical diagnostic separation from similar chondroid neoplasms. Awareness of these features is critical in avoiding pitfalls, including a malignant diagnosis of chondrosarcoma.

Diagnosis and Treatment of Calcium Pyrophosphate Deposition (CPPD) Disease: A Review

Calcium Pyrophosphate Dihydrate (CPPD) crystal-related arthropathies are a common cause of acute and chronic arthritis caused by the deposition of calcium pyrophosphate crystals in joints and soft tissues, resulting in inflammation and joint damage. They present with a wide spectrum of clinical manifestations and often present challenges to diagnosis and management as they commonly affect older co-morbid patients. The challenges are compounded by a lack of a well-defined description of CPPD. However, an international expert-driven process is underway to develop CPPD classification criteria. Treatment is also problematic as unlike gout, there are no agents available that decrease the crystal burden. Treatment options have often been extrapolated from gout treatment pathways without having extensive trials or a solid evidence base. It is hoped the new CPPD classification guidelines will contribute to large multicentre studies, with well-defined patient cohorts, which will facilitate the production of high-quality evidence to guide the management of this condition. Here, we discuss the barriers and facilitators in diagnosing and treating CPPD-related arthropathy.

Management of temporomandibular joint diseases: a rare case report of coexisting calcium pyrophosphate crystal deposition and synovial chondromatosis

BACKGROUND

The coexistence of calcium pyrophosphate dihydrate crystal deposition (CPP) and synovial chondromatosis (SC) in the temporomandibular joint (TMJ) is rarely reported. CPP disease (CPPD) is complex arthritis synonymous with excessive pyrophosphate production and variable aberrations in mineral and organic phase metabolism of the joint cartilage, leading to local inundated CPP and crystal deposition of partially deciphered predispositions. Meanwhile, SC is a rare benign synovial joint proliferative disease of unclear etiology and has a low risk of malignant transformation. However, SC manifests severe joint disability and dysfunction because of connective tissue metaplasia of the synovial membrane, which forms cartilaginous nodules with or without calcifications or ossifications. These nodules often detach and form intra-articular loose bodies and very rarely within extraarticular spaces.

CASE PRESENTATION

We report the case of a 61-year-old man to expand the body of literature on these unusual coexisting arthropathies of the TMJ. The patient presented to our hospital in 2020 with complaints of pain in the right TMJ and trismus for over 6 months. Radiographic assessments of the TMJ provided a preoperative provisional diagnosis of SC. However, the histopathology of the open biopsy revealed tumor-like lesions comprising several deposits of rhomboid and rod-shaped crystals that displayed positive birefringence in polarized light, confirming a coexistence of CPPD. A second-stage operation was performed for the complete removal of the loose bodies and chalk-like lesions including synovectomy. No evidence of recurrence was recorded after a follow-up of nearly 1.5 years.

CONCLUSIONS

Isolated CPPD and SC of the TMJ are prevalent in the literature however, monoarticular coexistence of these diseases is rare, due to the lack of consistency in the diagnostic criteria in clinical practice. Moreover, optimal treatment depends on several considerations. This report delineated the molecular etiopathology and underscored the need for continued deciphering of the causal mechanisms of coexisting CPPD and SC of the TMJ. In addition, the importance of confirmatory testing for accurate diagnosis, and appropriate management of these diseases were discussed.

An Unusual Pathologic Ulna Fracture Induced by Intraosseous Tumoral Calcium Pyrophosphate Dihydrate Crystal Deposition Disease

In this case report, we describe a novel occurrence of tumoral calcium pyrophosphate dihydrate crystal deposition disease (TCPPDCD) in a 76-year-old man that presented as an unusual, intraosseous, metadiaphyseal lesion of a long bone causing a pathologic fracture. A routine intralesional biopsy was performed, demonstrating granular deposits composed of polarizing, overlapping rhomboid crystals consistent with TCPPDCD. With limited numbers of reported cases of TCPPDCD, and the atypical intraosseous origin seen in this case, it is paramount to thoroughly evaluate all cases of TCPPDCD to clearly differentiate key findings that are essential in diagnosing and managing TCPPDCD.

Pathogenesis of calcium pyrophosphate deposition disease

Calcium pyrophosphate deposition disease is defined by the presence of calcium pyrophosphate (CPP) crystals in articular cartilage and is the fourth most common type of arthritis in adults. Despite its high prevalence, the etiology of CPPD disease remains unclear and no specific therapies currently exist. It has been known for several decades that abnormalities of cartilage pyrophosphate metabolism are common in patients with CPPD disease, and this classic work will be reviewed here. Recent studies of rare familial forms of CPPD disease have provided additional novel information about its pathophysiology. This work suggests that CPPD disease occurs through at least two unique and potentially intertwined biomolecular pathways. We are hopeful that a detailed understanding of the components and regulation of these pathways will lead to improved therapies for this common disease.

Imaging of facet joint diseases

Facet joints are the important articular pillars of the spine. Several pathologies can occur in and around the facet joint, including extra ossicles, traumatic dislocation, osteoarthritis, synovial cyst, axial spondyloarthritis, rheumatoid arthritis, calcium pyrophosphate deposition disease, septic arthritis, and malignant and benign neoplasms. Imaging is the mainstay to detect and characterize these diseases. In this review, we discuss the anatomy and function of facet joints, imaging techniques, and the imaging findings of several facet joint diseases. This information may be helpful to radiologists to make the correct diagnosis and optimize the management of patients with facet joint diseases.

Calcified chondroid mesenchymal neoplasms with FN1-receptor tyrosine kinase gene fusions including FGFR2, FGFR1, MERTK, NTRK1, and TEK: a molecular and clinicopathologic analysis

Translocations involving FN1 have been described in a variety of neoplasms that share the presence of a cartilage matrix and may also contain a variable extent of calcification. Fusions of FN1 to FGFR1 or FGFR2 have been reported in nine soft tissue chondromas, mostly demonstrated indirectly by FISH analysis. Delineation of FN1 fusions with various partner genes will facilitate our understanding of the pathogenesis and diagnostic classification of these neoplasms. In this study, we present molecular, clinical, and pathologic features of 12 cartilaginous soft tissue neoplasms showing a predilection for the TMJ region and the distal extremities. We analyzed for gene fusions with precise breakpoints using targeted RNA-seq with a 115-gene panel. We detected gene fusions in ten cases, including three novel fusions, FN1-MERTK, FN1-NTRK1, and FN1-TEK, each in one case, recurrent FN1-FGFR2 fusion in five cases, FN1-FGFR1 in one case, and FGFR1-PLAG1 in one case. The breakpoints in the 5' partner gene FN1 ranged from exons 11-48, retaining the domains of a signal peptide, FN1, FN2, and/or FN3, while the 3' partner genes retained the transmembrane domain, tyrosine kinase (TK) domains, and/or Ig domain. The tumors are generally characterized by nodular/lobular growth of polygonal to stellate cells within a chondroid matrix, often accompanied by various patterns of calcification, resembling those described for the chondroblastoma-like variant of soft tissue chondroma. Additional histologic findings include extensive calcium pyrophosphate dihydrate deposition in two cases and features resembling tenosynovial giant cell tumor (TGCT). Overall, while the tumors from our series show significant morphologic overlap with chondroblastoma-like soft tissue chondroma, we describe findings that expand the morphologic spectrum of these neoplasms and therefore refer to them as "calcified chondroid mesenchymal neoplasms." These neoplasms represent a spectrum of chondroid/cartilage matrix-forming tumors harboring FN1-receptor TK fusions that include those classified as soft tissue chondroma as well as chondroid TGCT.

Prevalence of chondrocalcinosis in the temporomandibular joint in patients with chondrocalcinosis of the knee or wrist

OBJECTIVE

The aim of this study was to investigate the prevalence of TMJ chondrocalcinosis on head CT scans in patients with chondrocalcinosis of the knee or wrist.

METHODS AND MATERIALS

227 patients with radiological evidence of calcifications on knee or wrist radiographs had a head CT scan obtained for unrelated purposes. CT scans were retrospectively reviewed for the presence of temporomandibular crystal deposition. Prevalence, bilaterality, age and gender distribution were determined.

RESULTS

41 of 227 (18%) of patients had TMJ chondrocalcinosis. TMJ chondrocalcinosis was more common in females (17%) than males (1%). It was more commonly unilateral (68%) than bilateral (32%).

CONCLUSION

In patients with peripheral calcific disease, the TMJ is more commonly involved than previously reported and this is more common in females compared to males.

Calcium pyrophosphate deposition disease: A case report with bilateral involvement of the temporomandibular joints and concurrence of psoriatic arthritis

Calcium pyrophosphate dehydrate deposition (CPDD) disease very rarely affects the temporomandibular joint (TMJ). It may resemble synovial chondromatosis, chondrosarcoma, chondroblastoma, or a parotid tumor. Clinical examination, CT, and MRI are important in making the correct diagnosis. Surgical removal of CPDD is necessary with or without excision of the TMJ.

A case of tophaceous pseudogout of the temporomandibular joint extending into the cranium

A case of tophaceous pseudogout (i.e., calcium pyrophosphate dihydrate crystal deposition disease) in the temporomandibular joint (TMJ) extending into the cranium is reported. A 59-year-old woman was referred to hospital with swelling and pain in the left cheek, and with trismus. Computed tomography imaging revealed a large, granular, calcified mass surrounding the left condylar head, partly destroying the cortex of the condylar head, and extending into the cranium by destroying the glenoid fossa. Magnetic resonance imaging revealed that the soft-tissue mass was of low-signal intensity on T1- and T2-weighted images, and was enhanced after intravenous injection of gadolinium. The mass was clinically and radiographically suspected to be a neoplastic lesion or a synovial osteochodromatosis. However, histological analysis demonstrated that the mass contained granulomatous lesion due to multiple nodular deposits of numerous rod-shaped and rhomboid crystals, which verified the diagnosis of tophaceous pseudogout. The lesion was excised surgically using a preauricular approach. Neither radiographic nor clinical examination demonstrated any signs of mass recurrence in the long-term 8- and 14-year postoperative recall examinations. Tophaceous pseudogout is a rare benign arthropathy that presents with clinical and radiographic features mimicking neoplastic conditions of the TMJ. Therefore, it is recommended that tophaceous pseudogout is considered in the differential diagnosis when a calcified mass lesion of the TMJ is encountered.

An Unusual Case of Huge Tophaceous Pseudogout Mimicking as a Tumor-Like Lesion around the Ankle Joint: A Case Report and Literature Review

Pseudogout or calcium pyrophosphate dihydrate deposition disease (CPPD) primarily affects the joints and the periarticular tissues. Tophaceous or tumoral pseudogout is a rare form of this disease which is seen around the joints of extremities. It can be misdiagnosed as a neoplastic condition because of its clinicoradiological similarities, and thus, a proper histopathological examination is indispensable. We report one such case of extra-articular deposition of the CPPD crystals in a 65-year-old man who presented with an asymptomatic swelling around the left ankle. Radiographs showed a dense homogenous calcification, and FNAC revealed dense calcium deposits with numerous rhomboid-shaped crystals. It was managed by en bloc excision, and postoperative biopsy reports confirmed the diagnosis. Possibility of pseudogout should be kept as a differential diagnosis in patients presenting with calcified soft tissue swellings and should be subjected to a detailed histopathological examination for confirmation.

Temporal mandibular joint chondrocalcinosis (tophaceous pseudogout) diagnosed by ultrasound-guided fine-needle aspiration

Tophaceous pseudogout is a calcium pyrophosphate dihydrate crystal (CPPD) deposition disease that frequently affects elderly patient in the temporomandibular joint (TMJ). A diagnosis of CPPD deposition disease in the TMJ is challenging due to its mimicking of other benign and malignant entities. Surgical exploration followed by histologic examination is by far the most frequently used diagnostic modality. We present a case of an 87-year-old female who presented with a right TMJ mass. A final diagnosis of tophaceous pseudogout was made on cellular material obtained by ultrasound-guided fine-needle aspiration (US-guided FNA). Based on our case and current available literature, ultrasound-guided FNA is a reliable tool for diagnosing tophaceous pseudogout of the TMJ.

Calcium pyrophosphate dihydrate deposition disease in the temporomandibular joint: diagnosis and treatment

Background

Calcium pyrophosphate dihydrate deposition disease (CPDD) is a rare disease in the temporomandibular joint (TMJ) space. It forms a calcified crystal mass and induces a limitation of joint movement.

Case presentation

The calcified mass in our case was occupied in the left TMJ area and extended to the infratemporal and middle cranial fossa. For a complete excision of this mass, we performed a vertical ramus osteotomy and resected the mass around the mandibular condyle. The calcified mass in the infratemporal fossa was carefully excised, and the segmented mandible was anatomically repositioned. Scanning electronic microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) microanalysis was performed to evaluate the calcified mass. The result of SEM/EDS showed that the crystal mass was completely composed of calcium pyrophosphate dihydrate. This result strongly suggested that the calcified mass was CPDD in the TMJ area.

Conclusions

CPDD in the TMJ is a rare disease and is difficult to differentially diagnose from other neoplasms. A histological examination and quantitative microanalysis are required to confirm the diagnosis. In our patient, CPDD in the TMJ was successfully removed via the extracorporeal approach. SEM/EDS microanalysis was used for the differential diagnosis.

Case report: Calcium pyrophosphate dihydrate deposition of the temporomandibular joint diagnosed by fine-needle aspiration cytology

Calcium pyrophosphate dihydrate deposition (CPDD) is the accepted name for a disease that mainly occurs in elderly patients. This disease affects many joints in particular the knee joint. CPDD is extremely rare in the temporomandibular joint (TMJ) with only few cases reported in the English literature. Herein, we present a case of an 89 years old woman with a radiological diagnosis of chondrosarcoma of TMJ. Fine-needle aspiration cytology however showed crystals, multinucleated giant cells and macrophages which allowed a correct diagnosis of CPDD.

Hyaline cartilage calcification of the first metatarsophalangeal joint is associated with osteoarthritis but independent of age and BMI

Background

Hyaline cartilage calcification (CC) is associated with osteoarthritis (OA) in hip and knee joints. The first metatarsophalangeal joint (1^stMTPJ) is frequently affected by OA, but it is unclear if CC occurs in the 1^stMTPJ. The aim of the present study was to analyze the prevalence of CC of the 1^stMTPJ in the general population by high-resolution digital contact radiography (DCR) and to determine its association with histological OA severity, age and body mass index (BMI).

Methods

168 metatarsal heads of 84 donors (n = 47 male, n = 37 female; mean age 62.73 years, SD ±18.8, range 20–93) were analyzed by DCR for the presence of CC. Histological OA grade (hOA) by OARSI was analyzed in the central load-bearing zone of the first metatarsal head (1^st MH). Structural equation modeling (SEM) was performed to analyze the interrelationship between CC, hOA, age and BMI.

Results

The prevalence of CC of 1^stMH was 48.8 % (41/84) (95 %-CI [37.7 %, 60.0 %]), independent of the affected side (p = 0.42), gender (p = 0.41) and BMI (p = 0.51). The mean amount of CC of one MH correlated significantly with that of the contralateral side (r_s = 0.4, 95 %-CI [0.26, 0.52], p < 0.001). The mean amount of CC (in % of total cartilage area) of the MH correlated significantly with the severity of hOA (r_s = 0.51, 95 %-CI [0.32, 0.65], p < 0.001). SEM revealed significant associations between CC and hOA (r = 0.74, p < 0.001) and between hOA and age (β = 0.62, p = 0.001), but not between CC and age (p = 0.15). There was no significant influence of BMI on either CC (p = 0.37) or hOA (p = 0.16).

Conclusion

The observation that CC of the 1^stMH is significantly associated with the severity of OA but independent of age and BMI, suggests an intimate relationship between CC and the pathogenesis of OA, the exact nature of which will have to be explored by future studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1324-0) contains supplementary material, which is available to authorized users.

Atypical Tumoral Presentation of Calcium Pyrophosphate Deposition Disease: A Case Report

CASE

A 55-year-old man presented with a history of forefoot pain and swelling. Radiographs revealed a mass with internal calcifications and osseous erosion of the fifth metatarsophalangeal bone. The mass was isointense to muscle on T1-weighted magnetic resonance imaging (MRI) and hyperintense on T2-weighted MRI. A biopsy was performed, and intraoperatively, the lesion appeared as chalky white material, which under polarized light microscopy was composed of weakly positively birefringent rhomboid crystals, leading to a diagnosis of tophaceous pseudogout.

CONCLUSION

Tophaceus pseudogout should be included in the differential diagnosis of neoplastic-appearing lesions in the foot, and polarized light microscopy should be used when examining biopsy specimens.

A case of tophaceous pseudogout of the temporomandibular joint extending to the base of the skull

A case of tophaceous pseudogout (i.e., calcium pyrophosphate dihydrate (CPPD) crystal deposition disease) in the temporomandibular joint (TMJ), extending to the base of the skull, is reported. A 38-year-old man was referred to the hospital with mild pain in the right chin and tip of the tongue. Panoramic radiography showed a large calcified mass around the right TMJ. Computed tomography imaging revealed a large, granular, calcified mass surrounding the right condylar head and extending to the base of the skull. The mass was clinically and radiographically suspected to be a pseudogout lesion. A biopsy specimen was collected under general anaesthesia to confirm the diagnosis. On histology, the mass was found to contain deposits of numerous rod-shaped and rhomboid crystals, which suggested tophaceous pseudogout. The deposits were identified as CPPD crystal deposition, based on analysis by X-ray diffraction and Fourier transform infrared spectroscopy. These two crystallography methods were useful in confirming the diagnosis of CPPD crystal deposition disease in the TMJ.

Tumoral pseudogout of the proximal interphalangeal joint of a finger: a case report and literature review

Tumoral pseudogout is a rare clinical form of calcium pyrophosphate dihydrate crystal deposition disease. Tumoral pseudogout can mimic other diseases such as chondroid tumor, tophaceous gout, or tumoral calcinosis. Its radiological features have been presented in some case reports, but no specific radiographic features have been identified. Here, we report an unusual case of recurrent tumoral pseudogout involving the proximal interphalangeal joint of the right long finger. This case presents with progressive radiological findings of the disease with an enlarging and recurrent calcified mass and secondary bony erosion and remodeling, along with a radiological-pathological correlation. We also review previously reported imaging findings of this disease entity, differential points in comparison to other diseases, and some key points for making the correct diagnosis.

Pseudogout of the Transverse Atlantal Ligament: An Unusual Cause of Cervical Myelopathy

Background:

Calcium pyrophosphate dihydrate deposition in the cervical spine is infrequently symptomatic. This is especially true at the craniocervical junction and upper cervical spine.

Case Report:

A 70-year-old previously healthy woman presented with a progressive cervical myelopathy of four months duration.

Results:

Examination revealed sensorimotor findings consistent with an upper cervical myelopathy. Radiological studies (plain radiographs, computed tomography, and magnetic resonance imaging) revealed C1-2 instability, and a well-defined extradural 3cm x 1cm retro-odontoid mass causing spinal cord compression. Transoral resection of the mass was performed followed by posterior C1-2 stabilization. Histological examination of the mass confirmed calcium pyrophosphate dihydrate deposition. Follow-up examination showed marked clinical and radiological improvement.

Conclusion:

Although uncommon, calcium pyrophosphate dihydrate deposition disease should be considered in the differential diagnosis of extradural mass lesions in the region of the odontoid.

A Rare Case of Tumoral Calcium Pyrophosphate Dihydrate Crystal Deposition Disease of the Wrist Joint

Introduction. Tumoral calcium pyrophosphate dihydrate (CPPD) crystal deposition disease (CPPDCD), also known as tophaceous calcium pyrophosphate deposition disease (CPDD), is a tumorlike lesion, and it should be distinguished from usual CPDD that causes severe joint inflammation and arthralgia. A case of tumoral CPPDCD of the wrist joint that required differentiation from synovial osteochondromatosis is described. Case Presentation. The patient was a 78-year-old woman with a 5-year history of nodular lesions at the right wrist that had gradually increased in size. An excisional biopsy and a histological examination of the excised nodular lesions by hematoxylin and eosin (H&E) staining were performed, demonstrating numerous polarizable, rhabdoid, and rectangular crystals, surrounded by fibroblasts, macrophages, and foreign body-type giant cells, consistent with tumoral CPPDCD. Conclusion. Tumoral CPPDCD, especially at the wrist joint, is rare, and, to the best of our knowledge, only 2 articles have been published. This case seems to need further follow-up for recurrence, because tumoral CPPDCD may recur after complete or incomplete surgical excision.

One-pot synthesis of highly greenish-yellow fluorescent nitrogen-doped graphene quantum dots for pyrophosphate sensing via competitive coordination with Eu(3+) ions

Highly fluorescent nitrogen-doped graphene quantum dots (N-GQDs) with greenish-yellow emission and quantum yield of 13.2% have been synthesized via a one-pot hydrothermal method. The obtained N-GQDs displayed excellent optical properties, high photostability and resistance to strong ion strength. Based on the higher affinity of pyrophosphate (PPi) than carboxyl and amido groups on the surface of the N-GQDs to Eu(3+), a Eu(3+)-modulated N-GQD off-on fluorescent probe for PPi detection was constructed with a detection limit of 0.074 μM. The detection process was simple in design, easy to operate, and showed a highly selective response to PPi in the presence of co-existing anions. This work widens the applications of N-GQDs with versatile functionality and reactivity in clinical diagnostics and as biosensors.

Imaging Approach to Temporomandibular Joint Disorders

Internal derangement is the most common temporomandibular joint disorder. Degenerative osteoarthritis and trauma are next in frequency. Less common pathology includes rheumatoid arthritis, synovial chondromatosis, calcium pyrophosphate dehydrate deposition disease, pigmented villonodular synovitis, tumors, infection, and osteonecrosis. We provide a systematic approach to facilitate interpretation based on major anatomic structures: disc-attachments, joint space, condyle, and lateral pterygoid muscle. Relevant graphic anatomy and state of the art imaging are discussed in correlation with current clinical and therapeutic highlights of pathologic entities affecting the joint.

Chondro-Osseous Lesions of Soft Tissue

Soft tissue lesions can contain bone or cartilage matrix as an incidental, often metaplastic, phenomenon or as a diagnostic feature. The latter category includes a diverse group ranging from self-limited proliferations to benign neoplasms to aggressive malignancies. Correlating imaging findings with pathology is mandatory to confirm that a tumor producing bone or cartilage, in fact, originates from soft tissue rather than from the skeleton. The distinction can have dramatic diagnostic and therapeutic implications. This content focuses on the gross, histologic, radiographic, and clinical features of bone or cartilage-producing soft tissue lesions. Recent discoveries regarding tumor-specific genetics are discussed.

Giant Solitary Synovial Osteochondroma of the Subtalar Joint

A rapidly progressing calcified mass was found in the left sinus tarsi in a 12-year-old female after a trivial ankle sprain. The lesion mimicked an aggressive lesion clinically and radiographically. Ultrasound-guided biopsy confirmed the diagnosis of a synovial chondroma. Excision of the tumor and partial synovectomy were performed. The histologic diagnosis was a solitary synovial osteochondroma. The condition had not recurred after a follow-up period of 12 months.

Calcium Pyrophosphate Dihydrate Crystal Deposition Disease of the Sternoclavicular Joint

Deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the articular structures affects predominantly temporomandibular, knee, hip, spine, and wrist joints, and is a rare condition, often mimicking malignancy. Sternoclavicular joint is extremely rarely involved. We present a patient with swelling of the right upper extremity, in whom on computed tomography a mass posterior to the sternoclavicular joint causing compression of the brachiocephalic vein was detected. A modified resection arthroplasty was performed, and the histopathological findings revealed massive deposits of CPPD in the articular cartilage. To our knowledge, there is only one similar case published in the literature.

Acute neck pain caused by arthritis of the lateral atlantoaxial joint

BACKGROUND CONTEXT

Many diseases can cause acute neck pain in elderly individuals. We conducted the present prospective study based on the hypothesis that arthritis of the lateral atlantoaxial joint may be involved in acute neck pain in elderly patients with limited neck rotation.

PURPOSE

To clarify whether the lateral atlantoaxial joint is involved in acute neck pain among elderly individuals by conducting lateral atlantoaxial joint puncture.

STUDY DESIGN

A prospective study.

PATIENT SAMPLE

Twenty-seven patients (13 men, 14 women) aged 50 years or more who provided consent for atlantoaxial joint puncture met the following four inclusion criteria: acute neck pain with limited cervical rotation of less than 20° as the chief complaint; visual analog scale pain score of 70 mm or more at initial visit; tenderness in the paraspinal muscle of upper cervical vertebrae; and serum C-reactive protein level of 0.5 mg/dl or more.

OUTCOME MEASURES

Visual analog scale pain score and radiologic findings.

METHODS

Patients underwent puncture of the lateral atlantoaxial joint and were evaluated clinically and radiologically.

RESULTS

Computed tomography obtained before puncture showed calcification of the transverse ligament of the atlas in the posterior dens in 22 patients (81.5%), calcification in the longus colli in 2 patients (7.4%), and no calcification in 3 patients (11.1%). Of 27 patients who underwent lateral atlantoaxial joint puncture, joint fluid was collected from 16 patients (59.3%) and calcium pyrophosphate dihydrate crystals were identified in 10 patients (62.5%). For the entire patient population, mean VAS score before puncture was 81.9±16.3 mm, significantly improving to 35.6±24.4 mm by 30 minutes after puncture (p<.001).

CONCLUSIONS

The results of this study suggest that crystal-induced arthritis (pseudogout) of the lateral atlantoaxial joint may be closely involved with acute neck pain in the elderly.

Tophaceous calcium pyrophosphate dihydrate deposition disease of the knee mimicking an aggressive soft tissue tumour

Calcium pyrophosphate crystal deposition disease (CPPD), previously pseudogout, is the second most common crystal arthropathy after gout. There is increased radiographic prevalence associated with age, trauma and several metabolic disorders. Tophaceous CPPD (T-CPPD) is a rare form of CPPD which, though non-neoplastic, mimics a bone or soft tissue malignancy. T-CPPD usually presents as a mass in the temporomandibular joint and occasionally in the paraspinal tissues, but rarely in the joints of the extremities. We present an exceptionally rare case of T-CPPD that was subtle on plain radiography, presenting as a soft tissue mass in the knee joint.

Nonpharmacologic and pharmacologic management of CPP crystal arthritis and BCP arthropathy and periarticular syndromes

Calcium crystal arthritis is often unrecognized, poorly managed, and few effective therapies are available. The most common types of calcium crystals causing musculoskeletal syndromes are calcium pyrophosphate (CPP) and basic calcium phosphate (BCP). Associated syndromes have different clinical presentations and divergent management strategies. Acute CPP arthritis is treated similarly to acute gouty arthritis, whereas chronic CPP and BCP arthropathy may respond to strategies used for osteoarthritis. Calcific tendonitis is treated with a variety of interventions designed to dissolve BCP crystals. A better understanding of the causes and larger well-planned trials of current therapies will lead to improved care.

Tophaceous pseudogout of the temporomandibular joint: a series of 3 cases

OBJECTIVE

We report a series of 3 cases of tophaceous pseudogout of the temporomandibular joint (TMJ).

STUDY DESIGN

Three patients, two men and one woman, ranging in age between 60 and 75 years, presented with unilateral painful swelling of the TMJ area associated with limitation of mouth opening.

RESULTS

Radiographic and computed tomographic images showed opaque masses in the supracondylar region of the TMJ. The preoperative clinical impression was a "neoplastic lesion" in the 3 cases. Microscopic examination revealed numerous deeply basophilic masses of calcified deposits, exhibiting birefringence under polarized light and morphologically consistent with calcium pyrophosphate dihydrate deposition, referred to in these cases as "tophaceous pseudogout."

CONCLUSION

Tophaceous pseudogout is a rare benign arthropathy that presents with clinical and radiographic features mimicking neoplastic conditions of the TMJ. Therefore, it is recommended that tophaceous pseudogout be considered in the differential diagnosis when a TMJ is involved with "neoplasm-like" lesions clinically and radiographically.

Huge tophaceous pseudogout associated with tenosynovial chondromatosis arising from flexor digitorum tendon sheaths of the foot: a case report

Synovial chondromatosis (SC) is a benign proliferative process of synovial tissue creating multiple cartilaginous nodules in joints. It most commonly occurs in the large joints of the knee, hip, and shoulder, uncommonly in the small joints of the hand and foot, and only rarely in the tenosynovial membrane of tendon sheath, termed tenosynovial chondromatosis (TC). Unlike SC, TC predisposes to the foot or hand. The rarity and unfamiliarity of imagers with TC, as well as the variability of its histologic features often lead to an erroneous diagnosis of extraskeletal chondroma or even chondrosarcoma as in the present case. Calcium pyrophosphate dehydrate (CPPD) crystals are usually deposited in the articular cartilage or periarticular structures such as synovium and capsule, and rarely in other soft tissue structures including bursa, tendon, subcutaneous tissue, and dura mater. CPPD crystals may also be deposited in extraskeletal chondroma and SC. We present an exceptionally rare case of huge tophaceous pseudogout associated with TC that is considered to arise from the flexor digitorum longus tendon sheaths of the foot, initially mistaken for a chondrosarcoma.

Tumoral Calcinosis Form of Hydroxyapatite Deposition Disease in Related Red-Bellied Short-Necked Turtles, Emydura subglobosa

Ten of 12 red-bellied short-necked turtles from a single clutch presented at 9 months of age with multiple white to tan nodules on their feet. Histologically, the nodules were composed of large periarticular deposits of mineralized crystalline material that extended into the joint spaces of interphalangeal joints and was surrounded by granulomatous inflammation and fibrosis. Crystallographic analysis determined the material to be apatite (calcium phosphate hydroxide) consistent with the tumoral calcinosis form of hydroxyapatite deposition disease (HADD). HADD has previously been described in aquatic turtles and rarely lizards and must be differentiated from gout in reptiles. A cause for the tumoral calcinosis lesions in these turtles could not be determined; however, based on previous reports in this species, a species-specific predilection, in conjunction with unknown environmental factors, is suspected. The use of the terms HADD, pseudogout (calcium pyrophosphate crystal deposition disease), and calcinosis circumscripta has been inconsistent, creating confusion in the literature.

Pseudotumors and Reactive Lesions

This article discusses reactive or degenerative processes in bone or periosteal soft tissue that occasionally masquerade as neoplasms. Presentation of the clinical, radiologic, and pathologic features of these processes is provided with an emphasis on the avoidance of overdiagnosis. Clinical, radiologic, and pathologic features of pseudotumors are presented in detail. This article approaches these tumor-like lesions in 2 categories: (1) those in the soft tissue next to bone and (2) those inside bones from the aspect of mineralization and calcification.

Mimicry in older patients: tophaceous pseudogout as a tumorlike lesion: a case report

Pseudogout is frequently seen in painful arthritis of larger joints, especially the knees and shoulders. This case report describes a rare clinical entity of soft-tissue calcium pyrophosphate dihydrate crystal deposition disease surrounding the second metatarsal bone of an 81-year-old man with moderate painful swelling of the right forefoot for 2 years. Diagnostic imaging demonstrated a calcified soft-tissue tumor adjacent to the second metatarsal bone by considering a neoplastic process in the differential diagnosis. Excisional biopsy revealed a chalklike material on the calcified soft tissue that was pathognomonic for chondrocalcinosis or pseudogout. The excisional biopsy findings led to stagnation of the clinical symptoms, and no recurrence of the initial tumor was seen during 12-month follow-up. In the literature, only 28 cases of tophaceous pseudogout tumors in the extremities have been described. In these cases, the lesions were suspected of being chondrosarcomas. For this reason, a correct diagnosis has to be pursued by performing a biopsy to treat the disease correctly.

Tophaceous pseudogout of the ankle: case report

Level of Evidence: V, Expert Opinion

Pseudogout of the temporomandibular joint: an uncommon cause of temporomandibular joint pain and swelling

BACKGROUND

Pseudogout, or calcium pyrophosphate deposition, is a rare cause of pain, swelling, and trismus of the temporomandibular joint (TMJ). Diagnosis and management of the lesion are discussed.

CASE DESCRIPTION

A 58-year-old female had a 2-month history of progressive swelling of right TMJ associated with trismus and facial pain. Imaging of the TMJ revealed a mixed radiolucent and radiopaque lesion associated with the right TMJ joint space. Surgical excision was performed successfully via preauricular approach. Pathology was consistent with calcium pyrophosphate deposition of the TMJ, also known as pseudogout. Surgical excision successfully treated her symptoms as expected. She is now disease free without recurrence.

CLINICAL IMPLICATIONS

Pseudogout is a rare cause of TMJ pain, swelling, and trismus that should be included in the differential of joint pain and dysfunction. It can be treated successfully with surgery.

Tophaceous pseudogout in the knee joint mimicking a soft-tissue tumour: a case report

Tophaceous pseudogout in the knee joint is rare. We report an 82-year-old man who presented with a one-year history of pain and swelling of the right knee joint. Treatment with non-steroidal anti-inflammatory drugs and aspiration of the joint effusion had not been effective. The mass continued to enlarge, and the patient had difficulty walking. Radiographs and computed tomography showed meniscal calcification with an abnormal soft-tissue mass surrounded by calcification. After excision, massive calcified deposits were seen both inside and on the surface of the tophaceous pseudogout. The deposits showed birefringence under polarised light, suggestive of calcium pyrophosphate dihydrate crystals. At the 2-year follow-up, the patient could walk independently without knee pain or swelling, although his range of knee motion was slightly limited due to joint contracture that developed before surgery.

Tumoral calcium pyrophosphate dihydrate crystal deposition disease: a rare diagnosis by fine-needle aspiration

Calcium pyrophosphate dihydrate crystal deposition disease (CPPD) is a well-recognized inflammatory joint disorder characterized by presence of calcium pyrophosphate dihydrate crystals in intraarticular and periarticular tissue. We report here a case of a 48-year-old male who presented with painless right hand swelling. Clinical suspicion was that of malignant soft tissue tumor. Fine-needle aspiration (FNA) yielded chalky white gritty material. Microscopic examination showed large areas of basophilic calcified material, histiocytes, giant cells and characteristic rhomboid shaped crystals. At places, chondroid material was also identified, hence, diagnosis of CPPD was made. This was confirmed on histopathological examination. Tophaceous/ tumoral pseudogout is a rare form of CPPD and it is important to recognize that this form can be diagnosed in FNA cytology (FNAC) and misdiagnosis of benign or malignant cartilaginous lesions can be avoided.

Articular gout and suspected pseudogout in a Basilisk lizard (Basilicus plumifrons)

A 9-yr-old male Basilisk lizard (Basilicus plumifrons) with a history of painful and limited mobility for approximately 4 mo, which had seemed to be more pronounced in the front limbs, was presented for necropsy. The animal had exhibited moderate weight loss and anorexia before euthanasia. Postmortem examination revealed yellow-to-white, soft-to-semifirm nodules within the periarticular fascia and musculature of the left and right shoulder joints, hip joints, and stifle joints. Several other joints, including the left and right tarsi, left and right elbow joints, and the left carpus had calcified, white material present on the articular surfaces. Histopathologic evaluation of representative sections of all organs and the joints confirmed tophaceous articular gout and articular pseudogout. The differentiation between articular gout and pseudogout was based on histologic appearance, histochemical staining for calcium, and birefringence under polarized light.