Increased signal of the fibular collateral ligament of the knee on MRI, clinically significant?

INTRODUCTION: The purpose of this study was to determine the clinical significance of signal hyperintensity in the proximal fibular collateral ligament (FCL) on coronal proton density (PD) fat-saturated (FS) MRI of the knee, a common finding. This study is unique in that it characterizes the FCL of a comprehensive, large cohort of both symptomatic and asymptomatic patients, which to our knowledge represents the first study with such broad inclusion criteria. METHODS: A large case series was performed analyzing MRI of the knee of 250 patients from July 2021 through September 2021 and retrospectively reviewed. All studies were performed on 3-Tesla MRI scanners with a dedicated knee coil and in accordance with standard institutional knee MRI protocol. Signal in the proximal fibular collateral ligament was assessed on coronal PDFS and axial T2-weighted FS images. Increased signal was classified as none, mild, moderate, or severe. A corresponding chart review of clinic notes was performed to determine the presence or absence of lateral knee pain. An FCL sprain or injury was considered present if the medical record described tenderness on palpation of the lateral knee, positive finding against resistance to the leg (varus stress test) or reverse pivot shift, or any clinical suspicion for lateral complex sprain or posterolateral corner injury. RESULTS: The majority (74%) of knee MRIs demonstrated the presence of increased signal in the proximal fibular collateral ligament on coronal PD FS images. <5% of these patients had associated clinical findings of fibular collateral ligament and/or lateral supporting structure injury. DISCUSSION: Although increased signal in the proximal FCL of the knee is a common finding on coronal PDFS images, the majority are not associated with clinical symptoms. Thus, this increased signal is likely not a pathological finding in the absence of clinical findings of fibular collateral ligament sprain/injury. Our study emphasizes the importance of clinical correlation in identifying increased signal in the proximal FCL as pathologic.

Malignancy in giant cell tumor of bone: analysis of an open-label phase 2 study of denosumab.

BACKGROUND: Giant cell tumor of bone (GCTB) is a rare osteoclastogenic stromal tumor. GCTB can rarely undergo malignant transformation. This post hoc analysis evaluated and classified malignancies in patients with GCTB who received denosumab. METHODS: This analysis was conducted on patients with pathologically confirmed GCTB and measurable active disease treated with denosumab 120 mg subcutaneously once every 4 weeks, with loading doses on study days 8 and 15, as part of a phase 2, open-label, multicenter study. We identified potential cases of malignancy related to GCTB through an independent multidisciplinary review or medical history, associated imaging or histopathologic reports, and disease course. The findings were summarized and no statistical analysis was performed. RESULTS: Twenty of five hundred twenty-six patients (3.8%) who received at least one dose of denosumab were misdiagnosed with GCTB that was later discovered to be malignancies: five primary malignant GCTB, five secondary malignant GCTB, four sarcomatous transformations, and six patients with other malignancies (giant cell-rich osteosarcoma, undifferentiated pleomorphic sarcoma, spindle cell sarcoma, osteogenic sarcoma, phosphaturic mesenchymal tumor of mixed connective tissue type, and fibrosarcoma/malignant fibrous histiocytoma). Many malignancies were present before denosumab was initiated (8 definitive cases, 7 likely cases), excluding potential involvement of denosumab in these cases. Signs associated with potential misdiagnoses of GCTB included poor mineralization with denosumab treatment, rapid relapse in pain, or a failure of the typical dramatic improvement in pain normally observed with denosumab. CONCLUSIONS: Although rare, GCTB can undergo malignant transformation, and rates in this study were consistent with previous reports. Signs of poor mineralization or lack of response to denosumab treatment may warrant close monitoring. TRIAL REGISTRATION: clinicaltrials.gov , ( NCT00680992 ). Registered May 20, 2008.

A Rare Anatomical Variant of Unilateral Piriformis Muscle Agenesis: A Case Report.

Anatomical variation of neuromuscular structures of the gluteal region is common. The piriformis muscle, in particular, has an important relationship with the sciatic nerve and may be associated with distinct clinical conditions. We report an incidental finding of unilateral piriformis muscle agenesis diagnosed on computed tomography and magnetic resonance imaging, a rare anatomical variant of the gluteal region.

Oncologic Accuracy of Image-guided Percutaneous Core-Needle Biopsy of Peripheral Nerve Sheath Tumors at a High-volume Sarcoma Center.

OBJECTIVES: Peripheral nerve sheath tumors (PNSTs) are clinically heterogenous, comprising benign (BPNST) and malignant (MPNST) variants. BPNSTs can be managed with nerve-sparing excision or observation. MPNSTs require radical resection and multidisciplinary oncologic management (1, 15). Image-guided core-needle biopsy (IGCNBx) is the well-established standard to obtain preoperative tissue diagnosis of soft tissue tumors. However, there has been resistance to performing IGCNBx of PNSTs because of the presumed risk of nerve injury and unknown accuracy in determining malignancy. We sought to define the accuracy and safety of IGCNBx in PNSTs. MATERIALS AND METHODS: All patients that underwent both IGCNBx and surgical resection of a PNST at our institution between 2002 and 2016 were analyzed. The accuracy of IGCNBx in determining malignancy was calculated, including subgroup analyses by histologic subtype and neurofibromatosis 1 status. Complication data were collected and analyzed. RESULTS: Among the 78 PNSTs with IGCNBx and postresection surgical pathology, 76% (n=59) had BPNST and 24% (n=19) had MPNST on postresection surgical pathology. IGCNBx accurately determined malignancy in 94% of cases. IGCNBx demonstrating schwannoma or MPNST were 100% accurate in determining malignancy. IGCNBx demonstrating neurofibroma or indeterminate results were 33% and 57% malignant on postresection surgical pathology, respectively. There were no long-term complications, including sensory or motor deficits, from IGCNBx. CONCLUSIONS: Percutaneous IGCNBx demonstrates 94% accuracy in differentiating benign from malignant PNSTs. IGCNBx demonstrating neurofibroma or indeterminate pathology should be interpreted with caution because of risk of malignant reclassification on surgical pathology. Our results reaffirm the safety of IGCNBx, as no patients experienced long-term complications.

Increased signal in the proximal patellar tendon: normal or pathologic?

OBJECTIVE: To determine the clinical significance of T2 signal hyperintensity in the proximal patellar tendon seen on MRI of the knee. MATERIALS AND METHODS: MRIs of 100 patients who underwent MRI of the knee between 1 May 2018 and 15 July 2018 were retrospectively evaluated. All examinations were performed on 3-Tesla MRI scanners with a dedicated knee coil and in accordance with our institution's standard knee MRI protocol. The presence of increased T2 signal was assessed on both sagittal and axial T2-weighted fat-saturated images. The amount of increased signal in the proximal patellar tendon on T2-weighted images was characterized as: none, mild, moderate, or severe. A corresponding chart review of the referring physicians' notes was performed to determine the presence of clinical symptoms of patellar tendinopathy. Patellar tendinopathy was considered present if the clinical notes described tenderness on palpation of the inferior patellar pole, infrapatellar tenderness, or patellar tendinosis/tendinitis. RESULTS: The majority (66%) of knee MRIs demonstrated the presence of increased T2 signal in the proximal patellar tendon. Only 4.5% of these patients had associated clinical findings of patellar tendinopathy. CONCLUSION: Although increased T2 signal in the proximal patellar tendon is a common finding, only in rare cases are there associated clinical symptoms. Thus, increased T2 signal in the proximal patellar tendon may not be a pathological finding in the absence of clinical findings of patellar tendinopathy.

Efficacy of intraarticular corticosteroid hip injections for osteoarthritis and subsequent surgery.

OBJECTIVE: Our study aimed to determine the duration of pain relief from intraarticular hip corticosteroid injections and identify patient predictive factors on injection response. We also sought to determine the subsequent rate of hip surgery and whether severity of hip osteoarthritis or injection response correlated with the decision to undergo surgery. MATERIALS AND METHODS: All intraarticular hip steroid injections performed for osteoarthritis under fluoroscopic guidance at a single institution between January 2010 to December 2012 were retrospectively reviewed. Response was divided into three groups: no relief, immediate (≤ 2 weeks of pain relief), and continued (> 2 weeks of pain relief). Presence of hip surgery for osteoarthritis performed within 2 years following injection was obtained. Correlation between patient characteristics with injection outcome and hip surgery was analyzed. RESULTS: Of 78 patients, a total of 82 injections were analyzed. For injections, 19.5% (16/82) showed no response, 47.6% (39/82) showed immediate response, and 32.9% (27/82) showed continued response. There was no significant correlation between injection outcome with age, Tönnis grade, BMI, or duration of symptoms. In total, 48.7% had hip surgery within 2 years after initial injection. There was a significant association between Tönnis grade and surgery, with higher Tönnis grades correlating with decision to undergo surgery (p = 0.002). CONCLUSIONS: Gender, age, BMI, duration of symptoms, and radiographic severity of disease do not predict injection response. Due to high surgical rates and poor response, intraarticular hip steroid injections may be less effective in the long term, and surgical management may be considered earlier.

Is Core Needle Biopsy Reliable in Differentiating Between Aggressive Benign and Malignant Radiolucent Bone Tumors?

BACKGROUND: Although there is widespread acceptance of core needle biopsy (CNB) for diagnosing solid tumors, there is reluctance by some clinicians to use CNB for aneurysmal bone cysts (ABCs) as a result of concerns of safety (bleeding, nerve injury, fracture, readmission, or infection) and reliability, particularly to rule out malignant diagnoses like telangiectatic osteosarcoma. This is especially true when CNB tissue is sent from an outside hospital, where the technique used to obtain the tissue may be spurious. QUESTIONS/PURPOSES: (1) Is CNB effective (provided adequate information to indicate appropriate surgical treatment without further open biopsy) as an initial diagnostic test for ABC? (2) Is CNB accurate (pathology consistent with the subsequent definitive surgical pathologic diagnosis) in differentiating between benign lesions such as primary or secondary ABCs and malignant radiolucent lesions such as telangiectatic osteosarcoma? (3) What are the complications of CNB? (4) Is there any difference in the effectiveness or accuracy of CNB performed at outside institutions when compared with a referral center? METHODS: A retrospective study of our musculoskeletal tumor board pathology database (1990-2016) was performed using search criteria "aneurysmal bone cyst" or "telangiectatic osteosarcoma." Only patients undergoing a CNB who proceeded to definitive surgical resection with final pathology were included. Excluding outside CNBs, CNB was performed after presentation at a musculoskeletal tumor board as a result of atypical features on imaging or history concerning for malignancy. Outside CNB tissue was reviewed by our pathologists. If there was sufficient tissue for diagnosis, the patient proceeded to definitive surgery. If not, the patient underwent open biopsy. CNB diagnosis, open biopsy results, and open surgical resection pathology were reviewed. Complications, including bleeding, infection, nerve injury, readmission, or fracture, between the CNB and definitive open surgical procedure (mean 1.6 months) were documented. CNBs were considered "effective" if they yielded pathology considered sufficient to proceed with appropriate definitive surgery without additional open biopsy. CNBs were considered "accurate" if they were effective and yielded a pathologic diagnosis that matched the subsequent definitive surgical pathology. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of obtaining a malignant diagnosis using CNB were also calculated. RESULTS: A total of 81% (59 of 73) of CNBs were effective. Ninety-three percent (55 of 59) of CNBs were classified as accurate. Diagnostic CNBs had a sensitivity and specificity of 89% (eight of nine) and 100% (51 of 51), respectively. The PPV was 1.00 and the NPV was 0.82. There were no complications. With the numbers available, there was no difference in efficacy (90% [37 of 41 versus 14 of 15]; odds ratio, 0.97 [95% confidence interval {CI}, 0.41-2.27], p = 0.94) or accuracy (92% [34 of 37 versus 13 of 14]; odds ratio, 0.87 [95% CI, 0.08-9.16], p = 0.91) between CNBs performed in house and those referred from outside. CONCLUSIONS: These data suggest that CNBs are useful as an initial diagnostic test for ABC and telangiectatic osteosarcoma. Tissue from outside CNBs can be read reliably without repeat biopsy. If confirmed by other institutions, CNB may be considered a reasonable approach to the diagnosis of aggressive, radiolucent lesions of bone. LEVEL OF EVIDENCE: Level III, diagnostic study.

Intraneural Hemangioma: Case Report of a Rare Tibial Nerve Lesion.

An intraneural hemangioma is a rare, benign mesodermal lesion. We present a case of a three-year-old female with the inability to straighten her right knee and fullness over the right popliteal fossa for one year. Magnetic resonance imaging (MRI) demonstrated a T2 hyperintense lesion of the popliteal fossa, within the tibial nerve. The patient underwent an uncomplicated right knee excisional biopsy, which confirmed the diagnosis of an intraneural hemangioma. Although rare, an intraneural hemangioma should be considered in the differential diagnosis of a soft tissue lesion located in the expected course of a peripheral nerve.

Synovial Tumors and Proliferative Diseases.

The clinical diagnosis of synovial tumors and synovial proliferative processes is difficult, as symptoms and physical examination findings are often nonspecific. Advanced imaging modalities, such as MRI, high-resolution ultrasound, and computed tomography, can aid clinical decision-making by providing accurate diagnosis of such diseases in many cases. This article focuses on those specific imaging features of synovial tumors and proliferative processes that can provide accurate diagnosis and guide appropriate patient management.

Surgical downstaging in an open-label phase II trial of denosumab in patients with giant cell tumor of bone.

BACKGROUND: Surgical resection with curative intent for giant cell tumor of bone (GCTB) may be associated with severe morbidity. This interim analysis evaluated reduction in surgical invasiveness after denosumab treatment in patients with resectable GCTB. METHODS: Patients with primary or recurrent GCTB, for whom the initially planned surgery was associated with functional compromise or morbidity, received denosumab 120 mg subcutaneously every 4 weeks (additional doses on days 8 and 15 of the first cycle). Planned and actual GCTB-related surgical procedures before and after denosumab treatment were reported. Patients were followed for surgical outcome, adverse events, and recurrence following resection. RESULTS: Overall, 222 patients were evaluable for surgical downstaging (54 % were women; median age 34 years). Lesions (67 % primary and 33 % recurrent) were located in the axial (15 %) and appendicular skeleton (85 %). At the data cutoff date, most patients had not yet undergone surgery (n = 106; 48 %) or had a less morbid procedure (n = 84; 38 %) than originally planned. Median (interquartile range) time on denosumab was 19.5 (12.4-28.6) months for the 106 patients who had not undergone surgery and were continuing on monthly denosumab. Native joint preservation was 96 % (n = 24/25) for patients with planned joint/prosthesis replacement and 86 % (n = 30/35) for patients with planned joint resection/fusion. Of the 116 patients who had surgery (median postsurgical follow-up 13.0 [8.5-17.9] months), local recurrence occurred in 17 (15 %) patients. CONCLUSION: For patients with resectable GCTB, neoadjuvant denosumab therapy resulted in beneficial surgical downstaging, including either no surgery or a less morbid surgical procedure.

Success rates for computed tomography-guided musculoskeletal biopsies performed using a low-dose technique.

OBJECTIVE: To evaluate the success rate of a low-dose (50% mAs reduction) computed tomography (CT) biopsy technique. This protocol was adopted based on other successful reduced-CT radiation dose protocols in our department, which were implemented in conjunction with quality improvement projects. MATERIALS AND METHODS: The technique included a scout view and initial localizing scan with standard dose. Additional scans obtained for further guidance or needle adjustment were acquired by reducing the tube current-time product (mAs) by 50%. The radiology billing data were searched for CT-guided musculoskeletal procedures performed over a period of 8 months following the initial implementation of the protocol. These were reviewed for the type of procedure and compliance with the implemented protocol. The compliant CT-guided biopsy cases were then retrospectively reviewed for patient demographics, tumor pathology, and lesion size. Pathology results were compared to the ultimate diagnoses and were categorized as diagnostic, accurate, or successful. RESULTS: Of 92 CT-guided procedures performed during this period, two were excluded as they were not biopsies (one joint injection and one drainage), 19 were excluded due to non-compliance (operators neglected to follow the protocol), and four were excluded due to lack of available follow-up in our electronic medical records. A total of 67 compliant biopsies were performed in 63 patients (two had two biopsies, and one had three biopsies). There were 32 males and 31 females with an average age of 50 (range, 15-84 years). Of the 67 biopsies, five were non-diagnostic and inaccurate and thus unsuccessful (7%); five were diagnostic but inaccurate and thus unsuccessful (7%); 57 were diagnostic and accurate thus successful (85%). These results were comparable with results published in the radiology literature. CONCLUSIONS: The success rate of CT-guided biopsies using a low-dose protocol is comparable to published rates for conventional dose biopsies. The implemented low-dose protocol did not change the success rate of CT-guided musculoskeletal biopsies.

Subcutaneous panniculitis-like T-cell lymphoma: MRI features and literature review.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) represents a rare subclassification of peripheral T-cell lymphoma (PTCL). We present a case of a 21-year-old female who presented with a 1-month history of pain in the left buttock and hip, tender left inguinal lymph nodes, fevers, and night sweats. Percutaneous core needle biopsy was diagnostic for SPTCL with CD8+ cells positive for cytotoxic granules. Magnetic resonance imaging (MRI) features of SPTCL with a review of the literature are discussed.

Intra-articular calcifications following arthroscopic ACL reconstruction: prevalence and possible significance.

PURPOSE: The goal of our study was to determine the frequency of intra-articular calcifications on initial postoperative radiographs following arthroscopic ACL reconstruction, describe their appearance, hypothesize their etiology, and determine their significance. MATERIALS AND METHODS: Review of records and post-operative radiographs for individuals undergoing arthroscopic ACL reconstruction at our institution identified 758 knees between November 2002 and April 2010. All patients underwent femoral and tibial tunnel drilling regardless of graft source. All but 23 underwent notchplasty. RESULTS: Intra-articular calcifications on initial postoperative radiographs were observed in 252 knees. The majority of calcifications were curvilinear, paralleling the posterior femoral condyles. Nineteen of the patients with calcifications on initial studies had repeat radiographs within 6 years. The calcifications resolved in every case. CONCLUSIONS: This study shows that intra-articular calcifications are a common finding on initial post-operative radiographs following ACL reconstruction. We feel they are of doubtful clinical significance, and in our limited experience, they eventually resolve. They should not be confused with chondrocalcinosis or vascular calcification.

Image-guided percutaneous core needle biopsy of musculoskeletal tumors in children.

The use of image-guided percutaneous core needle biopsy (PCNB) to obtain tissue diagnosis of musculoskeletal lesions has become the standard of care in adult patients with a success rate of over 80%. Previous reports indicate a similar success rate in diagnosing pediatric solid tumors. In this large study, we analyzed >10 years of data in which PCNB was used for tissue diagnosis of musculoskeletal lesions in children; we evaluated the histopathologic accuracy, anesthetic requirements, and complications of these procedures. In 122 children, tissue diagnosis was successfully obtained in 82% of cases, and there were 0 complications associated with the procedure. There was a significantly higher PCNB diagnostic success rate in malignant lesions (93%). These data suggest that the use of PCNB is a safe and effective means of diagnosing musculoskeletal lesions in children.

Correlation of MRI grading of bone stress injuries with clinical risk factors and return to play: a 5-year prospective study in collegiate track and field athletes.

BACKGROUND: Bone stress injuries are common in track and field athletes. Knowledge of risk factors and correlation of these to magnetic resonance imaging (MRI) grading could be helpful in determining recovery time. PURPOSE: To examine the relationships between MRI grading of bone stress injuries with clinical risk factors and time to return to sport in collegiate track and field athletes. STUDY DESIGN: Cohort study (prognosis); Level of evidence, 2. METHODS: A total of 211 male and female collegiate track and field and cross-country athletes were followed prospectively through their competitive seasons. All athletes had preparticipation history, physical examination, and anthropometric measurements obtained annually. An additional questionnaire was completed regarding nutritional behaviors, menstrual patterns, and prior injuries, as well as a 3-day diet record. Dual-energy X-ray absorptiometry was performed at baseline and each year of participation in the study. Athletes with clinical evidence of bone stress injuries had plain radiographs. If radiograph findings were negative, MRI was performed. Bone stress injuries were evaluated by 2 independent radiologists utilizing an MRI grading system. The MRI grading and risk factors were evaluated to identify predictors of time to return to sport. RESULTS: Thirty-four of the athletes (12 men, 22 women) sustained 61 bone stress injuries during the 5-year study period. The mean prospective assessment for participants was 2.7 years. In the multiple regression model, MRI grade and total-body bone mineral density (BMD) emerged as significant and independent predictors of time to return to sport. Specifically, the higher the MRI grade (P = .004) and lower the BMD (P = .030), the longer the recovery time. Location of the bone injury at predominantly trabecular sites of the femoral neck, pubic bone, and sacrum was also associated with a prolonged time to return to sport. Female athletes with oligomenorrhea and amenorrhea had bone stress injuries of higher MRI grades compared with eumenorrheic athletes (P = .009). CONCLUSION: Higher MRI grade, lower BMD, and skeletal sites of predominant trabecular bone structures were associated with a delayed recovery of bone stress injuries in track and field athletes. Knowledge of these risk factors, as well as nutritional and menstrual factors, can be clinically useful in determining injury severity and time to return to sport.

Imaging of the shoulder: a comparison of MRI and ultrasound.

Magnetic resonance imaging (MRI) is well established as a powerful imaging modality for the shoulder. In the last decade, ultrasound has emerged as an effective imaging option, alongside MRI, for evaluation of the shoulder. With MRI and ultrasound, clinicians now have two viable advanced imaging options for the diagnostic evaluation of shoulder pain. This article discusses the advantages and disadvantages of ultrasound and MRI for the shoulder. Applications where ultrasound is considered the imaging test of choice, those where MRI is more advantageous, and those where both ultrasound and MRI are viable alternatives for shoulder imaging are discussed.

Relevance of compartmental anatomic guidelines for biopsy of musculoskeletal tumors: retrospective review of 363 biopsies over a 6-year period.

PURPOSE: To retrospectively assess percutaneous core needle biopsies performed by radiologists and the association with tumor seeding along the biopsy tract when anatomic compartment guidelines are not consistently observed. MATERIALS AND METHODS: Retrospective data from computerized patient records and digital images from 363 consecutive computed tomography-guided biopsies of the lower extremity (thigh and leg) performed by radiologists at a single institution from August 2002 to August 2008 were analyzed for breaches of biopsy guidelines. RESULTS: Of the 363 biopsies, 243 (67%) were of soft tissue lesions and 120 (33%) were of bony lesions. There were 188 (52%) malignant and 175 (48%) benign lesions. The following biopsy breaches were observed: 13 (3.6%) of anatomic compartment, 42 (11.6%) of "vital structures," and 82 (68.3%) of needle path for bony tumors. Vital structures as defined by the literature included, but were not limited to, the following: knee joint capsule, greater trochanteric bursa, rectus femoris and vastus intermedius muscles, tibial tubercle, peroneus brevis and peroneus longus distal tendons, and neurovascular bundles. No cases of tumor recurrences could be attributed to needle seeding along a biopsy tract for any of these biopsy guideline breaches. CONCLUSIONS: The concern for needle tract seeding with musculoskeletal tumors is more widespread than the evidence supporting it as a significant or frequent complication. In this study, breaching anatomic compartment, vital structures (other than neurovascular structures), and suggested exact needle path guidelines were not associated with needle tract seeding in the lower extremity.

Chest wall sarcomas are accurately diagnosed by image-guided core needle biopsy.

OBJECTIVE: Sarcomas are rare mesenchymal malignancies. Accurate preoperative diagnosis is a prerequisite in considering investigational or institutional management algorithms that include neoadjuvant treatment. We reviewed our experience using core needle biopsy for chest wall sarcomas. METHODS: A retrospective review of our sarcoma databases revealed that 40 core needle biopsies and 35 tumor resections were performed in 34 patients, with chest wall musculoskeletal tumors, referred to the University of California, Los Angeles from 1991 to 2010. Primary, metastatic, or recurrent sarcomas involving the sternum, ribs, and soft tissues of the chest wall were evaluated for (1) adequacy of tissue from image-guided core needle biopsies and (2) accuracy in determining malignancy, histological subtype, and sarcoma grade. RESULTS: Twenty-eight of the 40 needle biopsy samples (70%) were adequate for histopathological analysis. Forty-two percent of nondiagnostic findings occurred due to insufficient tissue, whereas the remainder had sufficient tissue, but the pathologist was unable to determine specific histology. Excluding the nondiagnostic samples, the accuracy in determining malignancy, histological subtype, and grade in sarcomas was 100, 92, and 87%, respectively. The sensitivity and specificity of determining malignancy and high-grade sarcomas were 100, 100, 77, and 100%, respectively. There were no complications from the image-guided biopsies. CONCLUSIONS: We demonstrated that image-guided core needle biopsy when performed and reviewed by experienced radiologists and musculoskeletal pathologists is a safe and accurate diagnostic technique for chest wall sarcomas. Core needle biopsy should be considered in the multidisciplinary approach to chest wall musculoskeletal tumors, especially when induction therapy is considered.

Benign bone tumors.

A solid knowledge of underlying histopathology of benign bone tumors aids in differential diagnoses of these tumors. Important factors in diagnosis of a bone tumor include patient age and gender; the bone involved; the location of the tumor along, within, or on the bone; lesion margin; matrix proliferation; and periosteal reaction. This article provides a review of the origin of the tumor matrix and its influence on the imaging properties of these tumors.