Emerging factors affecting peri-implant bone metabolism

Implant dentistry has evolved to the point that standard implant osseointegration is predictable. This is attributed in part to the advancements in material sciences that have led toward improvements in implant surface technology and characteristics. Nonetheless, there remain several cases where implant therapy fails (specifically at early time points), most commonly attributed to factors affecting bone metabolism. Among these patients, smokers are known to have impaired bone metabolism and thus be subject to higher risks of early implant failure and/or late complications related to the stability of the peri-implant bone and mucosal tissues. Notably, however, emerging data have unveiled other critical factors affecting osseointegration, namely, those related to the metabolism of bone tissues. The aim of this review is to shed light on the effects of implant-related factors, like implant surface or titanium particle release; surgical-related factors, like osseodensification or implanted biomaterials; various drugs, like selective serotonin reuptake inhibitors, proton pump inhibitors, anti-hypertensives, nonsteroidal anti-inflammatory medication, and statins, and host-related factors, like smoking, diet, and metabolic syndrome on bone metabolism, and aseptic peri-implant bone loss. Despite the infectious nature of peri-implant biological complications, these factors must be surveyed for the effective prevention and management of peri-implantitis.

Diffuse-Type Tenosynovial Giant Cell Tumor: What Are the Important Findings on the Initial and Follow-Up MRI?

Tenosynovial giant cell tumor (TSGCT) is a rare soft tissue tumor that involves the synovial lining of joints, bursae, and tendon sheaths, primarily affecting young patients (usually in the fourth decade of life). The tumor comprises two subtypes: the localized type (L-TSGCT) and the diffuse type (D-TSGCT). Although these subtypes share histological and genetic similarities, they present a different prognosis. D-TSGCT tends to exhibit local aggressiveness and a higher recurrence rate compared to L-TSGCT. Magnetic resonance imaging (MRI) is the preferred diagnostic tool for both the initial diagnosis and for treatment planning. When interpreting the initial MRI of a suspected TSGCT, it is essential to consider: (i) the characteristic findings of TSGCT-evident as low to intermediate signal intensity on both T1- and T2-weighted images, with a blooming artifact on gradient-echo sequences due to hemosiderin deposition; (ii) the possibility of D-TSGCT-extensive involvement of the synovial membrane with infiltrative margin; and (iii) the resectability and extent-if resectable, synovectomy is performed; if not, a novel systemic therapy involving colony-stimulating factor 1 receptor inhibitors is administered. In the interpretation of follow-up MRIs of D-TSGCTs after treatment, it is crucial to consider both tumor recurrence and potential complications such as osteoarthritis after surgery as well as the treatment response after systemic treatment. Given its prevalence in young adult patents and significant impact on patients' quality of life, clinical trials exploring new agents targeting D-TSGCT are currently underway. Consequently, understanding the characteristic MRI findings of D-TSGCT before and after treatment is imperative.

Non‑surgical outcomes and risk factors for pulmonary metastasis from giant cell tumor of bone

The present study detailed four factors associated with an increased risk of pulmonary metastasis, age, pathological fracture, local recurrence and mode of treatment. Local recurrence and pathological fracture were independent risk factors for developing metastasis. From January 2016 to December 2021, data from 50 patients diagnosed with giant cell tumor of bone (GCTB) treated in Khon Kaen Hospital, Thailand, were retrospectively analyzed. The risk factors, including age at diagnosis, location of GCTB, clinical presentation, Campanacci stage and no. of local recurrences, for GCTB-induced pulmonary metastasis were evaluated using univariate and multivariable logistic regression analyses. Of the 50 patients analyzed, 9 patients (18%), with a mean age of 46.3 years (range, 18-68 years), developed pulmonary metastasis. No patients died from pulmonary metastasis in the present study. Statistically significant associations were observed between the development of metastasis and both clinical fracture [odds ratio (OR), 6.107; 95% confidence interval (CI), 1.08-34.70] and local recurrence (OR, 6.48; 95% CI, 1.03-40.87). Patients presenting with both a clinical fracture and local tumor recurrence require more rigorous clinical observation due to the significantly elevated risk of disease progression.

Arthroscopic treatment of intra-articular osteoid osteoma in the bicipital groove. A case report

INTRODUCTION AND IMPORTANCE

Rare presence of intra-articular osteoid osteoma may be difficult to diagnose due to the lack of typical radiographic features and clinical appearance similar to other articular pathologies. Additionally traditional treatment choices for osteoid osteoma may not suit the given environment of the shoulder joint area.

CASE PRESENTATION

We presented a 50-year-old male with a prolonged history of anterior shoulder pain and shoulder stiffness after physical activity. Intra-articular joint pathology was suspected after initial clinical and radiographic assessment. Magnetic resonance imaging revealed an osteoid osteoma in the humeral bicipital groove.

CLINICAL DISCUSSION

The surgical goal is to resect the benign bony tumour. Though the established treatment by open surgery or radiological minimally invasive techniques may not be optimal since pathologies in the shoulder joint cannot be addressed without the risk of damage to articular structures and increased complications. In this case to avoid joint incision site morbidity and address adjacent pathology arthroscopic removal of the tumour with refixation of the biceps longus tendon was carried out. At follow up of 12 months post-surgery physical activity did not provoke stiffness and resting pain has subsided.

CONCLUSION

Arthroscopic intra-articular osteoma resection in shoulder joint was optimal to address adjacent osteoma induced pathology, achieve great visualization, reduce incision site complication rates and achieve good results. Additional synovectomy during arthroscopic treatment can be performed, due to concomitant synovitis causing joint stiffness in most reported intra-articular OO cases.

Case Report: Giant Cell Tumor of Tendon Sheath After Breast Augmentation

Giant cell tumor of tendon sheath (GCTTS) is a benign tumor. It occurs predominantly in the hands, ankles, and knees. A 39-year-old female presented with GCTTS in the right breast after breast augmentation. There was a clear borderline between the tumor and breast tissue. In terms of morphological appearance, synovial metaplasia could be observed in part of the collagenous capsule. The tumor was moderately cellular and was composed of synovium-like monocytes. The main part of the tumor was blended with nested and scattered xanthomatous cells, lymphocytes, and osteoclast-like giant cells. Hemosiderin granules were distributed in the lesion. Immunohistochemical staining and fluorescence in situ hybridization (FISH) analyses were performed. CD68 staining was positive in osteoclast-like giant cells. In addition, neither significant USP6 translocation nor CSF1 translocation was detected by FISH. We hypothesized that the pathogenesis of this rare GCT-TS was based on synovial metaplasia and did not depend on the translocation of classical CSF1.

Intranuclear cell uptake and toxicity of titanium dioxide and zirconia particles as well as bacterial adhesion on dental titanium- and zirconia-implants

OBJECTIVE

Previous studies have shown that particles can be released from dental titanium (Ti)- and zirconia (ZrO₂)-implants. Titanium dioxide (TiO₂)- and ZrO₂-particles were compared regarding their toxicity and intranuclear cell uptake as well as the adhesion of various anaerobic bacteria on Ti- and ZrO₂-implants.

METHODS

Cyto- and genotoxicity of TiO₂-microparticles (TiO₂-MPs) and TiO₂-nanoparticles (TiO₂-NPs) in periodontal ligament (PDL)-hTERT cells were determined with XTT test and DNA damage with comet assay. Particle sizes of TiO₂- and ZrO₂-particles were measured with scanning electron microscope. Intranuclear uptake in PDL-hTERT cells was determined with laser scanning confocal microscopy. Adhesions of relevant anaerobic mouth bacteria Porphyromonas gingivalis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans on Ti- and ZrO₂-implants were investigated by cultivation and counting bacterial colonies.

RESULTS

Particle size measurements revealed that 99% of the TiO₂-NPs had a size below 100 nm and 88% of the TiO₂-MPs sizes were between 50 and 200 nm. Following EC₅₀ values were found for particles (mg/l): 92 (TiO₂-MPs) and 15 (TiO₂-NPs). A significant increase in olive tail moment (OTM) was found for TiO₂-NPs at a concentration of 1/10 EC₅₀. TiO₂- and ZrO₂-NPs had a higher intranuclear cell uptake efficiency, compared to corresponding TiO₂- and ZrO₂-MPs. All investigated particles could be detected in cell nucleus. Adhesion of all investigated bacterial species was significantly higher on Ti-implants, compared to ZrO₂-implants.

CONCLUSION

Ti usually develops an oxide layer (TiO₂). Particles released from Ti-implants should be TiO₂-particles or Ti-particles coated with a TiO₂-layer. Toxicity of released Ti-particles depends on their oxidation state and on their size (NP or MP). Particularly, NPs were more cyto- and genotoxic compared to the corresponding MPs. TiO₂- and ZrO₂-NPs showed a significant increase in the intranuclear cell uptake ratio at higher exposure concentration, compared to lower concentrations and consequently might lead to a higher potential of DNA damage. Adhesion of bacteria to ZrO₂-implants is reduced, compared to Ti-implants. Therefore, ZrO₂-implants might contribute to reduced biological complications (e.g. periimplantitis).

Stromal cells of giant cell tumor of bone show primary cilia in giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a locally aggressive primary bone neoplasm composed by tumoral stromal cells (SCs) and a reactive component that consists of monocytic/histiocytic cells that give rise by fusion to osteoclast-like multinucleated cells. Recently, specific Histone 3.3 mutations have been demonstrated in SCs of GCTB. Many of the pathways related to bone proliferation and regulation depend on the primary cilium, a microtubule-based organelle that protrudes outside the cell and acts as a sensorial antenna. In the present work, we aimed to study the presence and role of primary cilia in GCTB. Ultrastructural, immunohistochemical, and immunofluorescence studies were performed in order to demonstrate, for the first time, that the primary cilium is located in spindle-shaped SCs of GCTB. Moreover, we showed Hedgehog (Hh) signaling pathway activation in these cells. Hence, primary cilia may play a relevant role in GCTB tumorogenesis through Hh signaling activation in SCs. RESEARCH HIGHLIGHTS: Transmission electron microscopy allows describing and differentiating cellular subpopulations in giant cell tumor of bone (GCTB). The primary cilium is present in some tumoral stromal cells of GCTB. Hedgehog signalling is activated in these cells.

Arthroscopic removal as an effective treatment option for intra-articular osteoid osteoma of the knee

BACKGROUND

Intra-articular osteoid osteoma (iaOO) can be found in 5.2% up to 10% of cases. They may cause non-specific symptoms, mimicking degenerative or traumatic pathologies. If iaOO is left untreated, it may lead to severe muscle atrophy, tenderness, swelling, and limited range of motion. Therefore, surgical treatment is recommended. The main goal of surgical treatment is complete removal or destruction of iaOO.

AIM

To evaluate the efficiency of arthroscopic removal of iaOO of the knee in our cases and cases available in the literature.

METHODS

Analysis of available hospital records of four patients with iaOO of the knee treated by arthroscopic removal from August 2005 to December 2015 at our Department was performed. All patients had a diagnosis of iaOO confirmed by histopathologic analysis. Additional literature review of cases of iaOO of the knee available on PubMed and Google Scholar was made. All cases of iaOO of the knee treated by arthroscopic or arthroscopically assisted removal were reviewed in order to further evaluate the efficiency of the method.

RESULTS

The average age of patients included in our study was 23.2 (range 16-37) years. The average duration of the symptoms prior to surgery was 14.2 (range 6-24) months. All of the patients had persistent knee pain. Three patients reported worsening of pain during the night, while two reported worsening of pain during activity. Three patients reported alleviation of pain on non-steroidal anti-inflammatory drugs (NSAIDs), while one patient reported partial alleviation of pain on NSAIDs. No intraoperative complications were noted, and the postoperative period was uneventful in all patients. The patients reported immediate pain relief in the postoperative period. No recurrence of the disease was noted in any of the patients during the follow-up period of at least 24 mo. The literature review revealed 14 cases with an average age of 27.6 (range 16-48) years and onset of symptoms 27.7 (range 6-108) months prior to surgery, with recurrence of the disease noted in a single case.

CONCLUSION

Arthroscopic removal is an efficient treatment method that allows excision of iaOO that is neither insufficient nor excessive, thus avoiding disease recurrence while obtaining adequate material for histopathologic analysis.

Osteoclast-Like Giant Cells: Focus on Entities Relevant to Dermatopathology and Underlying Pathogenesis

ABSTRACT

Osteoclast-like giant cells (OLGCs) resemble osteoclasts with their abundant cytoplasm and well-developed organelles. OLGCs are characteristic features of giant cell tumor of the tendon sheath and giant cell tumor of soft tissue but they have also been described in numerous other cutaneous conditions. The diagnostic and prognostic significance of the presence of OLGCs is unknown. Here, we summarize the clinical entities that can exhibit these cells to avoid a histological overlap, affecting diagnosis and management.

Cancer regeneration: Polyploid cells are the key drivers of tumor progression

In spite of significant advancements of therapies for initial eradication of cancers, tumor relapse remains a major challenge. It is for a long time known that polyploid malignant cells are a main source of resistance against chemotherapy and irradiation. However, therapeutic approaches targeting these cells have not been appropriately pursued which could partly be due to the shortage of knowledge on the molecular biology of cell polyploidy. On the other hand, there is a rising trend to appreciate polyploid/ multinucleated cells as key players in tissue regeneration. In this review, we suggest an analogy between the functions of polyploid cells in normal and malignant tissues and discuss the idea that cell polyploidy is an evolutionary conserved source of tissue regeneration also exploited by cancers as a survival factor. In addition, polyploid cells are highlighted as a promising therapeutic target to overcome drug resistance and relapse.

Osteoid Osteoma Masquerading as Cholelithiasis: A Case Report

CASE

We present a case report of an 18-year-old woman who presented to a general surgeon with a several month history of intermittent right upper quadrant pain, strongly suggestive of symptomatic cholelithiasis and underwent a laparoscopic cholecystectomy. She was eventually found to have an osteoid osteoma (OO) of the right eighth rib. She was treated with radiofrequency ablation with complete resolution of symptoms 1 month after treatment.

CONCLUSIONS

In cases where a patient's age and risk factors would make the diagnosis of cholelithiasis less likely, OO should be added to the differential diagnosis of symptomatic right upper quadrant pain.

Clinical and immunohistochemical analysis of diffuse tenosynovial giant cell tumour of the temporomandibular joint

The objective of this study was to summarize diagnostic points and treatment strategies for diffuse tenosynovial giant cell tumours (D-TSGCTs) of the temporomandibular joint (TMJ), and to evaluate the expression of proteins related to bone destruction and recurrence. The clinical and histopathological characteristics of 24 cases were analysed retrospectively. TRAP staining and immunohistochemical staining for MMP-9, MMP-13, and Ki-67 were performed. The median age of the patients was 45.5 years; the female to male ratio was 1.7:1. In 11 cases (45.8%), skull base destruction seen on computed tomography was confirmed by surgery. Computer-assisted navigation was performed in six cases. Four patients received adjuvant radiotherapy after first surgery. Five patients had recurrent lesions. Multinucleated giant cells were positive for TRAP, MMP-9, and MMP-13. The average Ki-67 index of the recurrent cases was significantly higher than that of the non-recurrent ones (P<0.05). This study demonstrates the aggressive and recurrent nature of D-TSGCT occurring in the TMJ. Computer-assisted navigation is helpful to protect vital structures and determine margins. Adjuvant postoperative radiotherapy is recommended for local control of residual or recurrent tumour. In conclusion, MMP-9 and MMP-13 may play a role in bone destruction of D-TSGCT, and the Ki-67 index has predictive significance for recurrence.

Evaluation of giant cell tumors by diffusion weighted imaging-fractional ADC analysis

BACKGROUND

A single ADC value is used in clinical practice on multi b-value acquisitions. Low b-value acquisitions are affected by intravoxel incoherent motion, which is dependent on perfusion. Giant cell tumors (GCTs) are known to exhibit early arterial enhancement and low ADC values. Mean, minimum and fractional ADC characteristics of osseous and tenosynovial GCTs are systematically evaluated.

METHODS

Tenosynovial and osseous GCTs were included. Each lesion was evaluated on conventional MRI and DWI by two musculoskeletal radiologists. ADC was measured by placing an ROI on the most confluent enhancing portion of the lesion. Fractional and best fit ADC calculations were performed using MATLAB software.

RESULTS

No statistically significant difference was found between tenosynovial and osseous lesions' ADC values. Mean ADC for all lesions was 1.0 × 10^-3 mm²/s (SD = 0.2 × 10^-3 mm²/s) and minimum ADC was 0.5 × 10^-3 mm²/s (SD = 0.3 × 10^-3 mm²/s). Average mean ADC value obtained from B50-B400 slope was 1.1 × 10^-3 mm²/s (SD = 0.2 × 10^-3 mm²/s), and the average mean ADC value obtained from B400-B800 slope was 0.8 × 10^-3 mm²/s (SD = 0.1 × 10^-3 mm²/s) [p-value <0.01].

CONCLUSION

Tenosynovial and osseous GCTs demonstrate similar and low ADC values, which become even lower when using high b-value pairs. Our study also supports the theory of intravoxel incoherent motion that becomes apparent at low b values as related to giant cell tumors, which are known to be hyperperfused.

Arthroscopic Management of Osteoid Osteoma of the Ankle Joint: A Systematic Review of the Literature

Osteoid osteomas (OOs) are rare benign bone tumors that may occur in various joints including the ankle. These tumors are generally removed via open surgical excision or radiofrequency ablation. However, when they occur intra-articularly, these treatments are more difficult to perform because of more difficult access and the increased risk of damaging articular cartilage. Therefore, some have advocated for the use of arthroscopy to treat these cases. This systematic review aims to investigate the safety and efficacy of arthroscopic treatment for intra-articular OO of the ankle. Using Medline and Embase, we systematically reviewed the literature as of May 31, 2017. All articles published on and before that date were reviewed by 2 independent reviewers. Seventeen articles containing a total of 27 cases were included in the review. Most reported cases were in the talar neck, followed by the distal tibia. Of all the cases, only 2 recurrences were reported (in the same patient), and no complications were reported. Therefore, these cases demonstrate arthroscopic excision of intra-articular OO of the ankle as a safe and effective alternative to open surgical excision and radiofrequency ablation, with a success rate of 96%. However, all articles found were case studies or small case series owing to the rarity of this disease. In the future, analyses of case series with larger case collections should be performed.

An insight into the cannibalistic behavior of giant cell granulomas of the jaws

Background:

Cellular cannibalism is defined as a large cell engulfing a smaller one within its cytoplasm. It is predominantly a feature of aggressive malignancies but has recently been demonstrated in giant cell (GC) lesions such as GC tumor of tendon sheath, central GC granuloma (CGCG) and peripheral GC granuloma (PGCG).

Aim:

The aim of the study is to assess the cannibalistic GCs in CGCG and PGCG and correlate with aggressiveness of the lesion.

Settings and Design:

Archival data of histopathologically confirmed cases of CGCG (n = 40) and PGCG (n = 25) were studied in the Department of Oral Pathology, Maulana Azad Institute of Dental Sciences.

Materials and Methods:

Quantification of cannibalistic cells was performed using H&E stain on microscopic sections. One hundred GCs were examined in each slide, and the number of cannibalistic cells was expressed in percentage.

Results:

GC cannibalism was observed in all cases. The mean number of cannibalistic GCs in CGCG was 44.67 which was significantly higher (P = 0.028) than PGCG (mean 28.04). In aggressive (n = 18) CGCG, the mean number of cannibalistic GCs was 51.27 which was significantly higher (P = 0.019) than cannibalistic GCs in nonaggressive (n = 22) CGCG (mean 39.27). No significant difference was observed between the number of cannibalistic cells in recurrent (mean = 52.9) and nonrecurrent (mean = 49.2) cases of CGCG (P > 0.05). Two of the nine cases treated initially by steroid showed fewer and smaller cannibalistic GCs with vesicular nuclei.

Conclusion:

There was a clear distinction in the mean cannibalistic count between aggressive and nonaggressive CGCG. Hence, the aggressiveness of the lesion could be assessed following which appropriate treatment modality can be constituted.

CT-guided percutaneous cryoablation of an osteoid osteoma of the rib☆

An osteoid osteoma is a benign bone tumor that arises from osteoblastic dysfunction and usually presents as nonspecific, nocturnal pain located in the diaphysis of long bones, with <1% occurring in the ribs. It is most commonly treated with nonsteroidal anti-inflammatory drugs or merely observed; when these treatments do no prove efficacious, either open surgery or interventional ablation are pursued. Herein, we report a rare case of an osteoid osteoma located in the rib of a 19-year-old male that was histologically diagnosed through computed tomography (CT)-guided biopsy. Using CT guidance, the tumor was ablated by creating an artificial pneumothorax in order to induce a margin of space safe enough for cryoablation. It is important to be aware of the possibility that an osteoid osteoma may be present in the ribs, as the differential diagnosis includes costochondritis, pneumonia, osteoblastoma, enchondroma, osteosarcoma, cyst, and Brodie abscess. In addition, we have shown that CT-guided cryoablation can be an effective and less invasive treatment when compared to open en bloc resection, highlighting the role of interventional radiology in bone tumor ablation.

[Diagnostics and treatment of osteoid osteoma]

BACKGROUND

Osteoid osteoma is the third most common benign bone tumor and typically induces pain that is worse at night.

OBJECTIVE

To identify the epidemiological, pathogenetic, histological and radiological characteristics of osteoid osteoma and to present the broad variety of treatment options.

MATERIAL AND METHODS

This review article summarizes relevant clinical studies and meta-analyses on this topic.

RESULTS

Osteoid osteoma is characterized by a central nidus smaller than 1.5 cm in diameter with surrounding bone sclerosis. In the majority of cases, the tumor occurs in the long bones of the lower extremities and is predominantly manifested in patients aged between 5 and 25 years. Pain is mediated by prostaglandins, which stimulate afferent peripheral nerve fibers. Besides plain radiographs, thin-section computed tomography represents the gold standard of diagnostics but should be complemented by magnetic resonance or nuclear medicine imaging modalities. The conservative treatment consists of long-term therapy with non-steroidal anti-inflammatory drugs. Minimally invasive radiofrequency ablation of the nidus is the current operative treatment of choice.

CONCLUSION

Success rates of radiofrequency ablation and other minimally invasive procedures are high while treatment costs and length of hospital stay are low. Thus, open surgical curettage is reserved for rare indications and en bloc excision of the nidus should only be performed in cases of recurrent lesions.

A rare case of giant cell tumour (GCT) of bone with lung metastases

A case of 16-year-old girl with giant cell tumour of right fibula is presented to us with bilateral lung metastases. In view of widespread bilateral lung metastatic lesions, the patient was given multimodality treatment. Chemotherapy followed by radiotherapy to the local site as well as lung bath has been given and has shown good response.

Nanoparticles in dentistry

OBJECTIVE

Nanoparticles having a size from 1 to 100nm are present in nature and are successfully used in many products of daily life. Nanoparticles are also embedded per se or as byproducts from milling processes of larger filler particles in many dental materials.

METHODS AND RESULTS

Recently, possible adverse effects of nanoparticles have gained increased interest with the lungs being a main target organ. Exposure to nanoparticles in dentistry may occur in the dental laboratory, by processing gypsum type products or by grinding and polishing materials. In the dental practice virtually no exposure to nanoparticles occurs when handling unset materials. However, nanoparticles are produced by intraoral adjustment of set restorative materials through grinding/polishing regardless whether they contain nanoparticles or not. Nanoparticles may also be produced through wear of restorations or released from dental implants and they enter the environment when removing restorations. The risk for dental technicians is taken care of by legal regulations. Based on model worst case mass-based calculations, the exposure of dental practice personnel and patients to nanoparticles through intraoral grinding/polishing and wear is low to negligible. Accordingly, the additional risk due to nanoparticles exposure from present materials is considered to be low. However, more research is needed, especially on vulnerable groups (asthma or COPD). An assessment of risks for the environment is not possible due to the lack of data.

SIGNIFICANCE

Measures to reduce exposure to nanoparticles include intraorally grinding/polishing using water coolants, proper sculpturing to reduce the need for grinding and sufficient ventilation of treatment areas.

Diagnosing giant cell tumor of the bone using positron emission tomography/computed tomography: A retrospective study of 20 patients from a single center

The aim of the present study was to evaluate the sensitivity of positron emission tomography/computed tomography (PET/CT) in the diagnosis of giant cell tumor of the bone (GCTB) using the maximum standard uptake value (SUVmax), which indicates the metabolic rate of tissue. Patients diagnosed with pathologically confirmed GCTB between January 2006 and July 2015 were included in the study. Data from PET/CT scans and pathological and clinical reports for all patients were retrospectively reviewed. The SUVmax value from the PET/CT scan of each patient was retrieved and analyzed. A total of 20 patients [12 male and 8 female; age range, 12–45 years; mean age ± standard deviation (SD), 33.5±15.7] with complete PET/CT data and a pathologically and clinically confirmed diagnosis were examined. The SUVmax of GCTB was between 1.8 and 18.6, with a mean ± SD of 9.2±3.8. Although GCTB is not considered to be a malignant lesion, PET/CT scans of the tumors reveal high-grade malignant osseous sarcomas. It is, therefore, important not to mistake such lesions for osteosarcomas or metastatic malignancies of the bone.

Intra-Articular Osteoid Osteoma as a Cause of Anteromedial Knee Pain

A 32-year-old male patient presented to our clinic with chronic left knee pain that was ongoing for about 1.5 years. The patient visited several times our clinic and the other clinics; conservative treatment (including rest, knee brace, and ice application with NSAIDs) was recommended by various different doctors. The anamnesis, physical examination, and plain radiography were nonspecific. Early MRI findings mislead us to believe it is bone marrow edema. One and half years with noneffective treatment, the knee pain persisted. At the latest visit intra-articular osteoid osteoma was suspected and the knee MRI with CT was employed. Even though the diagnosis of intra-articular osteoid osteoma often presents a challenge for the surgeons, with a present awareness of intra-articular osteoid osteomas which lack the characteristic sclerotic lesions and nidus on plain X-rays and the aid of multislice CT, a correct diagnosis which warrants proper treatment can be achieved. The possibility of osteoid osteomas, especially in young adults with persistent knee pain with unknown reasons that show normal plain radiographs results, must not be overlooked. The treatment method of these lesions should be customized depending on the location of the lesion, experience of the surgeon, and cost of method.

Analysis of titanium and other metals in human jawbones with dental implants - A case series study

OBJECTIVE

The aim of this study was to measure titanium (Ti) content in human jawbones and to show that Ti was released from dental implants inserted into these jawbones.

METHODS

Seven samples from four human subjects with dental implants were analysed as test group and six bone samples of similar topographical regions from six human subjects without implants served as control. The contents of various elements in human jawbones were detected by inductively coupled plasma optical emission spectrometry. The distributions of various isotopes in human mandibular bone were measured with laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Histological analyses of undecalcified, Giemsa-Eosin stained mandible sections were performed by light microscopy and particles were identified in human bone marrow by scanning electron microscope-energy dispersive X-ray analysis.

RESULTS

In test group only Ti content was significantly higher compared to control group. The mean contents of Ti were 1940μg/kg in test group and 634μg/kg in control group. The highest Ti content detected in human mandibular bone was 37,700μg/kg-bone weight. In samples 4-7 (human subjects II-IV), increased Ti intensity was also detected by LA-ICP-MS in human mandibular tissues at a distance of 556-1587μm from implants, and the intensity increased with decreasing distance from implants. Particles with sizes of 0.5-40μm were found in human jawbone marrow tissues at distances of 60-700μm from implants in samples 4-7.

SIGNIFICANCE

Ti released from dental implants can be detected in human mandibular bone and bone marrow tissues, and the distribution of Ti in human bone was related to the distance to the implant.

Periarticular osteoid osteoma of the ankle: a report of nine arthroscopically treated patients

Periarticular osteoid osteoma often presents with unspecific clinical symptoms, mimicking other clinical conditions. This can lead a clinician to a ''diagnostic side path'' and a delayed or missed diagnosis compared with extra-articular osteoid osteoma. We report the cases of 9 patients with a mean age of 22 (range 14 to 32) years who were diagnosed with periarticular osteoid osteoma of the ankle and were surgically treated in our department during a 12-year period. The diagnostic difficulties associated with periarticular osteoid osteoma must be resolved by obtaining a detailed patient history and performing a thorough physical examination. Computed tomography is the ultimate imaging method to confirm the suspicion of osteoid osteoma. Arthroscopic removal of the osteoid osteoma was performed in all 9 patients in the present case series, with synovectomy performed when indicated. Under arthroscopic visualization, a specimen was obtained for histopathologic analysis to confirm the diagnosis, followed by tumor excision. All the patients were pain free at the final follow-up visit after a mean duration of 6 years (range 6 months to 12.7 years) postoperatively. We suggest arthroscopic removal of periarticular osteoid osteomas of the ankle as an effective treatment method, because it allows complete tumor excision, synovectomy when needed, a short postoperative rehabilitation period, and satisfactory functional results.

Pulmonary metastasis of giant cell tumor of bones

Giant cell tumor of bone (GCTB) accounts for 5% of primary skeletal tumors. Although it is considered to be a benign lesion, there are still incidences of pulmonary metastasis. Pulmonary metastasis of GCTB may be affected by tumor grading and localization as well as the age, gender and overall health status of the patient. Patients with local recurrence are more likely to develop pulmonary metastasis of GCTB. High expression of some genes, cytokines and chemokines may also be closely related to the metastatic potential and prognosis of GCTB. The treatment of the primary GCTB is key to the final outcome of the disease, as intralesional curettage has a significantly higher local recurrence and pulmonary metastasis rate than wide resection. However, even patients with pulmonary metastasis seem to have a good prognosis after timely and appropriate surgical resection. It is hoped that with the development of novel surgical methods and drugs, pulmonary metastasis of GCTB can be prevented and treated more effectively.

Intra-articular osteoid osteoma of the lateral tibial plateau treated with arthroscopically assisted removal and retrograde osteochondral grafting

The treatment of an intra-articular osteoid osteoma is sometimes challenging, because of its location. We report a patient with an intra-articular osteoid osteoma of the lateral tibial plateau which was excised under an arthroscopically assisted procedure. After total resection of the intra-articular osteoid osteoma, the osteochondral defect of the lateral tibial plateau was reconstructed with a retrograde autogenous osteochondral graft which was harvested from the non-weightbearing area of the distal femur.

Osteoid osteoma

Osteoid osteomas consist of a nidus with surrounding sclerotic bone. The differential diagnosis covers a wide range of conditions due to the variable presentation of osteoid osteoma. The natural history is for regression to occur within 6 to 15 years with no treatment; however, this can be reduced to 2 to 3 years with the use of aspirin and non-steroidal anti-inflammatory drugs. Computed tomography-guided percutaneous techniques, including trephine excision, cryoablation, radiofrequency ablation, and laser thermocoagulation, are described.

Chondroblastoma of the distal femur resected through a small fenestra via computed tomography navigation and endoscopy: a case report

INTRODUCTION

Chondroblastoma is a benign bone tumor with a relatively high incidence in older children and adolescents during the period of active epiphyseal growth. It is generally regarded as a benign neoplasm, but sometimes it grows aggressively or recurs. To prevent recurrence, complete curettage is important; however, such an approach can be extremely difficult to perform precisely when the chondroblastoma arises deep in the epiphysis. In our patient's case, we used a computed tomography-based navigation system with registration technique involving skin marker fiduciaries and endoscopic curettage of the lesion.

CASE PRESENTATION

A 16-year-old Japanese girl presented to our facility with left knee joint pain, which started nine months before her initial examination. Computed tomography and magnetic resonance imaging studies of the left knee showed a radiolucent lesion with marginal sclerosis and lobular homogeneous hypo-intensity and hyper-intensity signals in the distal epiphysis of the left femoral epiphysis, carried through to the growth plate. To prevent recurrence of chondroblastoma and growth disturbance, we used a computed tomography-based navigation system with registration technique involving skin marker fiduciaries and endoscopic curettage of the lesion. Wide excision with total removal of the chondroblastoma in the distal femur often requires large exposure with associated drawbacks, where a wide excision near the growth plate can potentially lead to growth disturbance. Therefore, in an accessible location in the distal femur, endoscopic excision of chondroblastoma under navigation system guidance can be performed with minimal operative damage.

CONCLUSIONS

In the setting of a benign intra-osseous lesion infiltrating the growth plate, arthroscopic retrieval or excision under a computed tomography-based navigation system should be considered before proceeding with open surgery.

Giant cell tumor of bone: a basic science perspective

Comprehending the pathogenesis of giant cell tumor of bone (GCT) is of critical importance for developing novel targeted treatments for this locally-aggressive primary bone tumor. GCT is characterized by the presence of large multinucleated osteoclast-like giant cells distributed amongst mononuclear spindle-like stromal cells and other monocytes. The giant cells are principally responsible for the extensive bone resorption by the tumor. However, the spindle-like stromal cells chiefly direct the pathology of the tumor by recruiting monocytes and promoting their fusion into giant cells. The stromal cells also enhance the resorptive ability of the giant cells. This review encompasses many of the attributes of GCT, including the process of giant cell formation and the mechanisms of bone resorption. The significance of the receptor activator of nuclear factor-κB ligand (RANKL) in the development of GCT and the importance of proteases, including numerous matrix metalloproteinases, are highlighted. The mesenchymal lineage of the stromal cells and the origin of the hematopoietic monocytes are also discussed. Several aspects of GCT that require further understanding, including the etiology of the tumor, the mechanisms of metastases, and the development of an appropriate animal model, are also considered. By exploring the current status of GCT research, this review accentuates the significant progress made in understanding the biology of the tumor, and discusses important areas for future investigation.

Fibrohistiocytic tumors and related neoplasms in children and adolescents

Fibrohistiocytic tumors (FHTs) in children and adolescents range from the benign fibrous histiocytoma, or dermatofibroma, to a variety of intermediate and malignant neoplasms, such as dermatofibrosarcoma protruberans and high-grade undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma). Those tumors as a group are comprised of fibroblasts, myofibroblasts, and histiocytes-dendritic cells with a variably prominent inflammatory infiltrate consisting of lymphocytes and eosinophils. Dendritic cells are also a major constituent of another group of neoplasms that include Langerhans cell histiocytosis, follicular and interdigitating cell sarcomas, and juvenile xanthogranuloma. These latter tumors are considered in this discussion for the sake of differential diagnosis and their possible histogenetic relationship to FHTs. Recent studies have suggested that the relationship between the fibroblast and histiocyte in the FHTs may reflect the intrinsic capacity to transdifferentiate from one to the other morphologic and functional state. The so-called "facultative fibroblast," as a cell with fibroblastic and histiocytic properties, was discussed in the context of the fibrous xanthoma 50 years ago. Possibly the entire histogenetic concept of FHTs should be reconsidered in light of current studies.

Arthroscopic removal of an intra-articular osteoid osteoma of the radial styloid

We describe a case of intra-articular osteoid osteoma arising in the radial styloid of a 21-year-old man. Plain radiographs were not diagnostic, but computed tomography, gadolinium-enhanced magnetic resonance imaging, and bone scintigraphy suggested the possibility of an osteoid osteoma. We arthroscopically removed the lesion; histological examination confirmed the diagnosis. The patient's symptoms disappeared immediately after surgery.

Similarities Between Giant Cell Tumor of Bone, Giant Cell Tumor of Tendon Sheath, and Pigmented Villonodular Synovitis Concerning Ultrastructural Cytochemical Features of Multinucleated Giant Cells and Mononuclear Stromal Cells

The authors investigated ultrastructural cytochemical features of multinucleated and mononuclear stromal cells in giant cell tumor of bone (GCTB), giant cell tumor of tendon sheath (GCTTS), and pigmented villonodular synovitis (PVNS). Specimens of each tumor, respectively numbering 4, 4, and 3, were stained for tartrate-resistant acid phosphatase (TRAP) reactions and examined with an electron microscope. In GCTB and GCTTS, multinucleated cells, including some relatively small giant cells, showed TRAP activity and cytoplasmic features characteristic of osteoclasts, and also sometimes abundant rough endoplasmic reticulum and siderosomes. A few giant cells with macrophage-like features and slight TRAP activity were demonstrated in GCCTS and PVNS. In each tumor type, mononuclear cells showing TRAP activity shared cytoplasmic features with osteoclast-like multinucleated giant cells, while some others had macrophage-like features, and still others were poorly differentiated; a few mononuclear cells showed cell-to-cell contact. Ultrastructural similarities of TRAP-positive mononuclear cells in the three tumor types, and those between TRAP-positive multinucleated cells in GCTB and GCTTS, suggest a common cell lineage capable of multinucleated giant cell formation in the 3 tumors, despite differing histogenesis.

FDG uptake in giant cell tumor of the tendon sheath in a patient restaged for gastrointestinal stroma tumor (GIST)

A 70-year-old man known for recurrent abdominal gastrointestinal stroma tumor presented with a suspicious peritoneal mass demonstrated by an abdominal CT scan. Whole-body PET showed focal FDG uptake in the right hip, whereas the peritoneal mass was FDG negative. Histologic work-up of the PET positive lesion surprisingly revealed a giant cell tumor of the tendon sheath. The benignity of the peritoneal mass was confirmed by its disappearance in repeated CT scans. In general, focally increased FDG uptake should be subject to further investigations, especially in localizations that are not consistent with typical metastatic pathways of the former primary tumor.

Giant cell tumor of the rib occupying the entire hemithorax

The authors report the case of a 28-year-old female patient with a giant cell tumor originating from the rib. The tumor, measuring 25 x 17 cm, occupied the entire hemithorax and caused atelectasis of the left lung. This tumor was a benign mesenchymal neoplasm, which rarely affects the ribs. A thoracotomy involving en bloc resection of the chest wall and tumor was performed. Despite the large dimensions of the tumor, complete resection was possible, and lung function was restored.