Spindle Cell Squamous Cell Carcinoma of the Larynx with Malignant Osteoid Differentiation: A Case Report and Review of Literature.

Spindle cell squamous cell carcinoma of the larynx is a rare, aggressive variant of squamous cell carcinoma. It comprises 0.6-1.5% of all laryngeal cancers. Heterologous mesenchymal differentiation as bone, cartilage, and muscle is uncommon, especially malignant osteoid differentiation, as a handful of cases reported in the literature. We present the case of a 66-year-old male active smoker who presented with dysphonia and acute stridor. On examination, a 2.0 cm pedunculated, broad-base, glottic mass involving the left true vocal cord and ventricle was noted, with extension to the anterior commissure causing a narrowing of the airway. The patient underwent localized left vocal cordectomy. The histopathologic and immunohistochemical findings were consistent with spindle cell carcinoma with malignant osteoid differentiation. The patient is alive, status-post adjuvant five cycles of cisplatin therapy, with no recurrence at 18 months of follow-up. We discuss a literature review of this rare entity with either malignant osteoid or osteocartilaginous differentiation.

Imaging-guided radiofrequency ablation of osteoid osteoma in typical and atypical sites: Long term follow up.

PURPOSE: To assess efficacy and safety of imaging-guided radiofrequency ablation (RFA) of Osteoid Osteoma (OO) in both typical and atypical sites. METHODS AND MATERIALS: Between January 2014 and March 2019, 102 consecutive percutaneous RFA were performed and retrospectively reviewed. The procedures were performed using a RFA bipolar ablation system (Covidien, exposed tip of 0.7-1cm), under Computed Tomography (CT) guidance or using a navigation system (Masmec) under CT and Cone Beam CT (CBCT) guidance. Patients were followed up over 24 months. Clinical success and recurrences were considered on the base of established criteria. In patients with clinical failure and/or imaging evidence of relapse, retreatment was considered. RESULTS: Administered power per-procedure was ≤8 W (mean temperature, 90°C). The pre-procedure average value of visual analog scale (VAS) was 8.33+/-0.91. Primary and secondary success rate 96.08% (98/102) and100% (102/102), respectively. No major complication was described. Technical success was proved in every patient by CT scan acquisition after needle positioning. Relapse and tumour location were significantly correlated (p-value = 0.0165). The mean dose-length product was 751.55 mGycm2. Advanced bone healing was noted in 68 lesions after 1y-follow up and in 86 lesions after 2y-follow up. CONCLUSION: Imaging-guided percutaneous RFA is a highly effective technique for OO, both in typical and atypical sites. CT or CBCT guidance, navigation systems and operator experience grant the technical success, which is the most crucial parameter affecting outcome.

Surgery Versus Radiofrequency Ablation in the Management of Spinal Osteoid Osteomas: A Spine Oncology Referral Center Comparison Analysis of 138 Cases.

BACKGROUND: Osteoid osteomas (OOs) are benign bone forming tumors that, usually, occur in the extremities, with about 10% of them arising in the spine more commonly in the posterior elements. The aim of this study is to evaluate the long-term results of patients suffering from spinal OO treated with surgery and radiofrequency ablation. METHODS: This was a retrospective comparison analysis of data prospectively collected from 2 cohorts of consecutive patients diagnosed with OO of the spine treated at the same Institute from November 2002 to February 2019. The first cohort included patients submitted to an intralesional extracapsular excision of the lesion (surgery group); the second cohort included patients submitted to radiofrequency ablation (RFA group). RESULTS: The surgery group showed a local recurrence rate of 1.7% versus a recurrence rate of 12.5% in the RFA group with a statistically significant difference in the disease-free survival at longest follow-up (P = 0.012). No statistically significant differences were observed in local recurrence rate stratified for level and site of lesion. No complications were observed in both groups at the time of first procedure. CONCLUSIONS: Surgery and RFA are both safe and effective interventional procedures for the management of spinal OO, although RFA is associated with a greater recurrence rate. Treatment should be tailored according to the relationship of lesions with neural structures and to advantages and disadvantages of each technique.

[An adolescent man with pain at night in his lower right leg]. / Een jonge man met nachtelijke pijn in een scheenbeen.

A 22-year-old man is referred to the orthopaedic surgeon. He has pain, mostly at night, in his proximal right tibia that greatly reduces with NSAIDs. The CT scan shows a focal lucent zone, called a nidus, in the tibia cortex, surrounded by reactive, sclerotic bone. This is typical for an osteoid osteoma, a benign bone tumour.

Bone Tumors: Benign Bone Tumors.

Primary benign bone tumors are uncommon and most often affect children and young adults. They typically are detected incidentally on imaging, though some patients present with pain, swelling, or other symptoms. The four main categories of benign bone tumor are: bone-forming (eg, osteoid osteoma, osteoblastoma, fibrous dysplasia, enostosis), cartilage-forming (eg, osteochondroma, enchondroma), connective tissue, and vascular; the latter two are rare. A fifth category is idiopathic (eg, giant cell tumor, aneurysmal bone cyst, simple bone cyst). Osteochondromas are the most common, accounting for 30% to 35% of benign bone tumors. Giant cell tumors account for 20%, osteoblastomas for 14%, and osteoid osteomas for 12%. All others are less common. Diagnosis mainly is via imaging; biopsy rarely is required. Management varies with tumor type, location, symptoms, and risk of recurrence. Some (eg, enchondroma, osteochondroma, fibrous dysplasia, enostosis) typically are asymptomatic, and generally require no intervention. Others (eg, osteoid osteoma, aneurysmal bone cyst, simple bone cyst) can cause symptoms and require percutaneous ablation or surgery. Still others (eg, giant cell tumor, osteoblastoma) can be aggressive and require surgery and other therapies. Malignant transformation is rare for all benign bone tumors, but patients with these tumors should be monitored with serial imaging.

Multidisciplinary approach in the treatment of osteoid osteoma with radiofrequency ablation.

OBJECTIVES: This study aims to present the importance of a multidisciplinary approach to radiofrequency ablation (RFA) treatment in osteoid osteoma (OO) patients by a team of experts in their field in preventing recurrence and complications. PATIENTS AND METHODS: For this retrospective study, a team of two orthopedists, two interventional radiologists, and one anesthesiologist was established in January 2013 to manage the diagnosis, follow-up, and treatment process of patients with OO at Bakirköy Dr. Sadi Konuk Training and Research Hospital. A total of 27 patients (15 males, 12 females; mean age 22.9 years; range, 9 to 54 years) were treated by this team between February 2013 and September 2016. The anatomic localization included iliac crest in four patients, the femur in 12 patients, fibula in two patients, humerus in three patients, radius in one patient, tibia in three patients, talus in one patient, and metacarpal in one patient. The procedures were carried out by the same interventional radiologists, same orthopedic surgeons, and same anesthesiologist in the computed tomography (CT) unit under aseptic conditions. After appropriate anesthesia for the localization of OO, the patient was positioned on the CT bed and the localization of the lesion was confirmed with a CT scan mapping. Then, a bone penetration cannula was advanced and bone cortex was penetrated with a charged motor and Kirschner (K)-wire. When the cannula reached the nidus, it was replaced with RFA probe. Ablation of the nidus was performed for five minutes at 90°C. RESULTS: The mean follow-up period was 46 months (range, 25 to 66 months). Patients were evaluated with visual analog scale (VAS) scores preoperatively and at postoperative 15th day, sixth month, and first year. In the last evaluation of the study data, the patients were called by telephone and questioned whether there were any changes in their final status. The mean preoperative VAS score was 7.2. The mean postoperative VAS scores of the 15th day, sixth month, and first year were 1.3, 0.6, and 0, respectively. In the last follow-up, the OO-related pain completely disappeared and none of the patients had any recurrence. There was a significant difference between preoperative and postoperative 15th day and sixth month VAS score measurements. CONCLUSION: Radiofrequency ablation treatment of OOs is a minimally invasive, safe, low-cost, and efficient method. We believe that with experienced teams and appropriate planning, RFA will take part in practice as the standard treatment of OO.

Osteoma osteoide raquídeo recidivante en forma de osteoblastoma agresivo / Spinal osteoid osteoma recurring as an aggressive osteoblastoma

Presentamos el caso de un osteoma osteoide recurrente en forma de un osteoblastoma agresivo en columna lumbar. Un varón de 15 años acudió a nuestro servicio con una escoliosis dolorosa. El TC y la RM mostraron una tumoración formadora de hueso esclerótico de 7 mm compatible con un osteoma osteoide. Se realizó una ablación percutánea guiada por radiofrecuencia con remisión completa de la sintomatología. Seis meses después, dicha sintomatología recurrió. Se realizaron TC y RM que mostraron un crecimiento del nidus en la lámina L4 derecha, con un diámetro de 15 mm. Se realizó una resección marginal. La histología mostró un osteoblastoma epiteloide. Un años después, se realizaron nuevos estudios de imagen que mostraron una nueva recurrencia del tumor con rasgos agresivos e invasión del canal espinal. Se le realizó una cirugía de resección en bloque con estabilización de la columna lumbar. La histología confirmó el diagnóstico de osteoblastoma epiteloide

We report an uncommon case of osteoid osteoma recurring as an aggressive osteoblastoma of the spine. A 15-years-old male consulted in our department with long-term painful scoliosis. The CT-scans and MRI revealed a sclerotic bone forming tumor of 7 mm diameter consistent with a osteoid osteoma. A percutaneous radiofrequency ablation was performed with complete resolution of the symptoms. After 6 months, the symptoms recurred. A new CT and a MRI showed a growth of the nidus on the right L4 lamina, with a size of 15 mm. Therefore, a marginal resection by laminectomy of L4 was performed. Pathology confirmed an epithelioid osteoblastoma. A year later, subsequent imaging studies showed a new recurrence with aggressive features and invasion of the spinal canal. The patient then underwent an "in block surgery" needing concurrent stabilization of the spine. Histopathology confirmed the diagnosis of epithelioid osteblastoma

[An update for the treatment of osteoid osteoma]. / Le point sur le traitement percutané des ostéomes ostéoïdes.

Osteoid osteoma is frequent benign tumor, descripted initially by Bergstrand in 1930 followed by Jaffe in 1935. The painful feature of the osteoid osteoma explains the specific consideration by the medical community for this entity. The debate was focused on pathologic and imaging pattern as well as the treatment modalities. Currently, the treatment options are varied and percutaneous treatment is increasingly used. The radiofrequency is widely validated as efficient method without serious adverse and with low rate of recurrence. We hope through this this work to revue the current knowledge of the treatment of osteoid osteoma.

L'ostéome ostéoïde est une tumeur osseuse bénigne relativement fréquente initialement décrite par Bergstrand en 1930, puis comme une entité propre grâce aux recherches de Jaffe en 1935. Malgré sa bénignité, elle a concentré toute l'attention des radiologues comme des cliniciens car très symptomatique. Dès lors, l'ostéome ostéoïde a fait l'objet de nombreux débats dans la communauté scientifique en particulier concernant son étiologie, ses caractéristiques pathologiques, son bilan d'imagerie et son traitement. C'est sur cette dernière question que les avancées ont été les plus marquantes et c'est ainsi que les possibilités thérapeutiques bien décrites dans la littérature apparaissent variées. Toutefois, les résultats très favorables des traitements percutanés et en particulier de la radiofréquence, de même que le faible taux de récidives et de complications de ces traitements, ont amené de nombreux pays à les considérer comme le meilleur traitement en première intention. A travers cette revue de la littérature et de notre pratique clinique, nous souhaitons rapporter les connaissances actuelles thérapeutiques en perpétuelle progression grâce au progrès technique.

Complications of Computer Tomography Assisted Radiofrequency Ablation in the Treatment of Osteoid Osteoma.

BACKGROUND: Osteoid osteoma (OO) is one of the most commonly occurring benign bone tumors. It constitutes 10-12% of benign bone tumors and 2-3% of primary bone tumors. In radiofrequency ablation (RFA) treatment, the cells of the tumor are thermally inactivated by the help of electrodes shaped like needles. In our study, we aimed to show the major and minor complications in patients undergoing RFA and to show what should be done to prevent these complications. METHODS: The study was carried out as a prospective study on the follow-up of 87 osteoid osteoma patients treated between 2015 and 2017. The youngest of the patients was 1 year old and the oldest was 42 years old. The RFA procedure lasted 10 min on average, excluding anesthesia and preparation. All lesions were ablated at 90 degrees for 7 minutes with the heat increased gradually. All patients were followed up for 1 day in the orthopedics clinic. RESULTS: Complications were observed in 7 patients. The lesions with the most complications were observed to be in the tibia, second-degree burns were seen in 2 patients, and superficial skin infection was observed in 2 patients. In 1 patient, the probe tip was broken and remained within the bone. Intramuscular hematoma was detected in 1 lesion located in the proximal femur. A complaint of numbness in the fingers developed in a lesion located in the metacarpus. CONCLUSION: Preventive measures should be taken before the procedure in order to prevent minor complications, and, for major complications, close follow-up should be done after the procedure and patients should be kept away from heavy physical activities for the first 3 months.

Prolonged heating in nontargeted tissue during MR-guided focused ultrasound of bone tumors.

BACKGROUND: Thermal dosimetry during MR-guided focused ultrasound (MRgFUS) of bone tumors underpredicts ablation zone. Intraprocedural understanding of heat accumulation near bone is needed to prevent undesired treatment of nontargeted tissue. HYPOTHESIS: Temperature decay rates predict prolonged, spatially varying heating during MRgFUS bone treatments. STUDY TYPE: Prospective case series. PATIENTS: Nine patients with localized painful bone tumors (five bone metastasis, four osteoid osteomas), were compared with five patients with uterine fibroid tumors treated using MRgFUS. FIELD STRENGTH/SEQUENCE: Proton resonance frequency shift thermometry using 2D-GRE with echo-planar imaging at 3 T. ASSESSMENT: Tissue response was derived by fitting data from extended thermometry acquisitions to a decay model. Decay rates and time to peak temperature (TTP) were analyzed in segmented zones between the bone target and skin. Decay rates were used to calculate intersonication cooling times required to return to body temperature; these were compared against conventional system-mandated cooling times. STATISTICAL TESTS: Kolmogorov-Smirnov tests for normality, and Student's t-test was used to compare decay rates. Spatial TTP delay and predicted cooling times used Wilcoxon signed rank tests. P < 0.05 was significant. RESULTS: Tissue decay rates in bone tumor patients were 3.5 times slower than those in patients with fibroids (τbone = 0.037 ± 0.012 vs. τfibroid = 0.131 ± 0.010, P < 0.05). Spatial analysis showed slow decay rates effecting baseline temperature as far as 12 mm away from the bone surface, τ4 = 0.015 ± 0.026 (median ± interquartile range [IQR]). Tissue within 9 mm of bone experienced delayed TTP (P < 0.01). In the majority of bone tumor treatments, system-predicted intersonication cooling times were insufficient for nearby tissue to return to body temperature (P = 0.03 in zone 4). DATA CONCLUSION: MRgFUS near bone is susceptible to long tissue decay rates, and unwanted cumulative heating up to 1.2 cm from the surface of the bone. Knowledge of decay rates may be used to alter treatment planning and intraprocedural thermal monitoring protocols to account for prolonged heating by bone. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2019;50:1526-1533.

Osteoid Osteoma About the Hip in Children and Adolescents.

BACKGROUND: The etiology of hip pain in pediatric and adolescent patients can be unclear. Osteoid osteoma (OO) about the hip in children has only been described in case reports or small studies. The present study assessed the clinical presentation and diagnostic course, imaging, and treatment approaches in a large cohort of pediatric cases of OO about the hip. METHODS: Medical record and imaging results were reviewed for all cases of OO identified within or around the hip joint in patients <20 years old between January 1, 2003, and December 31, 2015, at a tertiary-care pediatric center. Demographic, clinical, and radiographic data were analyzed. RESULTS: Fifty children and adolescents (52% female; mean age, 12.4 years; age range, 3 to 19 years) were identified. Night pain (90%) and symptom relief with nonsteroidal anti-inflammatory drugs (NSAIDs) (88%) were common clinical findings. Sclerosis/cortical thickening was visible in 58% of radiographs, although a radiolucent nidus was visible in only 42%. Diagnostic imaging findings included perilesional edema and a radiolucent nidus on 100% of available magnetic resonance imaging (MRI) and computed tomography (CT) scans, respectively. Initial alternative diagnoses were given in 23 cases (46%), the most common of which was femoroacetabular impingement (FAI). Delay in diagnosis of >6 months occurred in 43% of patients. Three patients underwent operative procedures for other hip diagnoses, but all had persistent postoperative pain until the OO was treated. Of the 41 patients (82%) who ultimately underwent radiofrequency ablation (RFA), 38 (93%) achieved complete post-RFA symptom resolution. CONCLUSIONS: Initial misdiagnosis, the most common of which was FAI, and delayed correct diagnosis are common in pediatric OO about the hip. Presenting complaints were variable and nonspecific MRI findings were frequent. Night pain and relief with NSAIDs were present in the vast majority of cases. CT scans provided definitive diagnosis in all patients who received them. As increasing numbers of young, active patients are being evaluated for various causes of hip pain, such as FAI, OO should not be overlooked in the differential diagnosis. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Hand osteoid osteoma: evaluation of diagnosis and treatment.

BACKGROUND: OO (osteoid osteoma) is a common, osteoblastic, benign bone tumor but rarely seen in the hand region. There is still some debate about the diagnosis and treatment of hand OOs. In the present study, we aimed to evaluate the epidemiology, radiologic features, surgical treatment options and functional outcomes. METHODS: Between January 2003 and December 2014, surgically treated and pathologically verified 9 hand OO cases were investigated retrospectively. The preoperative and postoperative clinical outcome scores were calculated using the M2-DASH (Manchester-Modified Disabilities of Arm Shoulder and Hand) Score. RESULTS: Lesion locations were as follows: middle phalanx in 2/9 (22%) patients (2nd and 4th digit), proximal phalanx in 6/9 (67%) patients (one 4th, two 2nd and three 5th digits) and metacarpal (2nd) in 1/9 (11%) patient. Incidence of nidus formation was 6/9 (67%) on X-ray, 7/9 (78%) on CT imaging and 2/9 (22%) on MR imaging. The mean time to diagnosis was 13.22 ± 5.44 months. Preoperative mean M2-DASH score was 41 ± 6 and postoperative was 7.4 ± 8.6. CONCLUSION: Osteoid osteoma is usually seen below 25 years, and rarely found over 40 years of age. There is male dominance with a male to female ratio of 3:1. Delay of diagnosis may be encountered because of many differential diagnoses. When OO is suspected, CT imaging should be taken before the MR imaging. Because of superiority in soft tissue imaging, MR imaging should be an alternative tool in complex cases.

Percutaneous Radiofrequency Ablation of Spinal Osteoid Osteomas Using a Targeted Navigational Bipolar Electrode System.

Safe and effective percutaneous CT-guided radiofrequency ablation of spinal osteoid osteomas can be performed using a targeted navigational bipolar electrode system. Articulating bipolar electrodes with built-in thermocouples along an electrode shaft and variable generator wattage settings allow optimal nidus access, particularly in challenging locations; provide precise real-time monitoring of ablation zone volume and geometry; and minimize the risk of undesired thermal injury.

Targetability of osteoid osteomas and bone metastases by MR-guided high intensity focused ultrasound (MRgHIFU).

PURPOSE: To retrospectively evaluate the suitability of MRgHIFU for osteoid osteomas (OOs) and bone metastases in patients who underwent minimally-invasive percutaneous thermal ablation. MATERIALS AND METHODS: One hundred and sixty-seven lesions (115 metastases and 52 OOs) treated percutaneously between October 2014 and June 2017 were retrospectively analyzed. Tumors were located in the spine or sacrum (54), pelvis (43), limbs (50), ribs (17) and sternum (3). Tumor volume, matrix, anatomical environment and need for protection of surrounding structures or consolidation were assessed. Cases were classified into three categories: (a) lesions suitable for MRgHIFU therapy alone; (b) lesions suitable for MRgHIFU if protection of surrounding structures and/or bone consolidation is performed; (c) lesions not suitable for MRgHIFU. RESULTS: Twenty-six (50%) of OOs were classified as suitable for MRgHIFU alone and 17 (32.7%) as suitable for MRgHIFU with hydro-dissection. Matrix of treatable OOs was sclerotic (19), lytic (15) or mixed (9), with mean volume 0.56 cm3. Forty-one (35.7%) of metastases were classified as suitable for MRgHIFU alone and 43 (37.4%) as suitable with hydro-dissection and/or consolidation. Matrix of metastases was sclerotic (13), lytic (37) or mixed (34), with mean volume 71.9 cm3. Mean depth of targetable lesions was 50.9 ± 28.4 mm. 97.7% of pelvic lesions and 94% of peripheral bone lesions were targetable by HIFU. 66.6% of spinal or sacral lesions were considered untreatable. CONCLUSION: MRgHIFU cannot be systematically performed non-invasively on bone tumors. Combination with minimally-invasive thermo-protective techniques may increase the number of eligible cases.

Cystic bone tumors of the foot and ankle.

Bone tumors are relatively rare in the foot and ankle region. Many of them present as cystic lesions on plain films. Due to the relative rarity of these lesions and the complex anatomy of the foot and ankle region, identification of such lesions is often delayed or they get misdiagnosed and mismanaged. This review discusses the most common cystic tumors of the foot and ankle including their radiographic features and principles of management.

Ribbing disease: a systematic review.

Background Ribbing disease, or multiple diaphyseal sclerosis, is a rare benign bone dysplasia. Purpose To systematically review the literature to determine the clinical and radiological presentation of patients with Ribbing disease as well as the effects of attempted treatments. Material and Methods We considered individual patient data of patients diagnosed with Ribbing disease derived from patient reports and patient series. All stages of the review were performed by two reviewers independently. Standard descriptive statistics were used for quantitative analyses and mixed model analyses were used when appropriate Results The literature search yielded 420 unique hits of which 23 studies were included, covering a total of 40 patients of whom 29 had bilateral involvement. The mean age at diagnosis was 35 years and the mean time between diagnosis and onset of symptoms, mostly pain, was five years (range = 1-16 years). The tibial diaphysis was the most commonly involved bone in 35 of 36 patients. Non-surgical treatment consisted of non-steroidal anti-inflammatory drugs (NSAIDs), prednisone, and bisphophonates with mixed results. Surgical treatment consisted of intramedullary reaming and fenestration and was very effective to reduce pain. Conclusion The clinical presentation and imaging findings of patients with Ribbing disease are becoming more apparent. However, there is paucity of evidence on the natural disease progression and effectiveness of treatment modalities.

Technical aspects of osteoid osteoma ablation in children using MR-guided high intensity focussed ultrasound.

BACKGROUND: Osteoid osteoma (OO) is a painful bone tumour occurring in children and young adults. Magnetic resonance imaging-guided high intensity focussed ultrasound (MR-HIFU) allows non-invasive treatment without ionising radiation exposure, in contrast to the current standard of care treatment with radiofrequency ablation (RFA). This report describes technical aspects of MR-HIFU ablation in the first 8 paediatric OO patients treated in a safety and feasibility clinical trial (total enrolment of up to 12 patients). MATERIALS AND METHODS: OO lesions and adjacent periosteum were treated with MR-HIFU ablation in 5-20 sonications (sonication duration = 16-48 s, frequency = 1.2 MHz, acoustic power = 20-160 W). Detailed treatment workflow, patient positioning and coupling strategies, as well as temperature and tissue perfusion changes were summarised and correlated. RESULTS: MR-HIFU ablation was feasible in all eight cases. Ultrasound standoff pads were shaped to conform to extremity contours providing acoustic coupling and aided patient positioning. The energy delivered was 10 ± 7 kJ per treatment, raising maximum temperature to 83 ± 3 °C. Post ablation contrast-enhanced MRI showed ablated volumes ranging 0.46-19.4 cm3 extending further into bone (7 ± 4 mm) than into soft tissue (4 ± 6 mm, p = 0.01, Mann-Whitney). Treatment time ranged 30-86 min for sonication and 160 ± 40 min for anaesthesia. No serious treatment-related adverse events were observed. Complete pain relief with no medication occurred in 7/8 patients within 28 days following treatment. CONCLUSIONS: MR-HIFU ablation of painful OO appears technically feasible in children and it may become a non-invasive and radiation-free alternative for painful OO. Therapy success, efficiency, and applicability may be improved through specialised equipment designed more specifically for extremity bone ablation.

Noninvasive Therapy for Osteoid Osteoma: A Prospective Developmental Study with MR Imaging-guided High-Intensity Focused Ultrasound.

Purpose To demonstrate that magnetic resonance (MR) imaging-guided high-intensity focused ultrasound (HIFU) is a safe, effective, and durable treatment option for the management of osteoid osteoma in children and young adults. Materials and Methods This prospective study was institutional review board approved and is registered with clinicaltrials.gov (identification number NCT02302651). Written informed consent was obtained from patients or their parents. Patients who had both clinical and radiologic findings that were diagnostic for nonvertebral osteoid osteoma and no contraindications to MR imaging-guided HIFU were enrolled between June 2010 and June 2013. The feasibility, safety, and clinical effectiveness of MR imaging-guided HIFU were considered primary outcomes; tumor control at imaging was considered a secondary outcome. Analyses were conducted on a per-protocol basis. Results Forty-five of the 50 recruited patients underwent MR imaging-guided HIFU. All patients were discharged without treatment-related complications. The median visual analog scale (VAS) pain score (scale, 0-10) decreased from 8 before treatment to 0 at 1-week and 1- , 6- , 12- , 24- , and 36-month follow-up. Similarly, median VAS scores for the degree to which pain interfered with sleep and physical and daily activities decreased to 0 within the 1st month after treatment and remained stable at subsequent follow-up. Overall, 39 (87%) of the 45 patients achieved and maintained a VAS score of 0 during the 3-year observation period. Quality of life, as assessed by using Functional Assessment of Cancer Therapy-Bone Pain (FACT-BP) scores (scale, 0-60 points), improved, with the median FACT-BP score of 28 (points) before treatment increasing to a median score of 55 at 1-week follow-up and 60 at 6-month and subsequent follow-ups. At (final) 36-month follow-up, MR imaging depicted an absence of residual nidus vascularity in 32 (76%) of the 42 patients who were treated with MR imaging-guided HIFU only. Conclusion The durable clinical efficacy and safety of MR imaging-guided HIFU were demonstrated. These features are evidence of the potential of MR imaging-guided HIFU to be part of a routine strategy for the treatment of osteoid osteoma. © RSNA, 2017.

Intra-articular benign bone lesions treated with Magnetic Resonance-guided Focused Ultrasound (MRgFUS): imaging follow-up and clinical results.

Purpose of this study was to evaluate the employment of MRI-guided Focused Ultrasound (MRgFUS) for treatment of intra-articular benign bone lesions as alternative to surgery, and to monitor the success of the treatment on CT and MRI images. From March 2011 to August 2013, 14 intra-articular benign bone lesions were treated with MRgFUS. All patients were studied by CT and MR imaging. Pain was measured using the visual analogue scale (VAS) before and after treatment (6 and 12 months). All patients in our series demonstrated regression in painful symptomatology during screening. A significant drop in the mean VAS pain score (from 7.8 to 0.6) was observed at 12-month follow-up, and pain medication was no longer needed after treatment. No complications were observed. Three diagnostic imaging signs were found suggesting absence of biological activity and confirming the clinical findings: calcification of the treated lesion, lack of contrast enhancement and disappearance of bone oedema around the lesions. CONCLUSION: the employment of MRgFUS is safe and effective in the treatment of intra-articular benign bone lesions. The clinical outcome is satisfactory, and the success of the treatment is confirmed by diagnostic imaging.