Chronic Nonspinal Osteomyelitis in Adults: Consensus Recommendations on Percutaneous Bone Biopsies from the Society of Academic Bone Radiologists.

The diagnosis and management of chronic nonspinal osteomyelitis can be challenging, and guidelines regarding the appropriateness of performing percutaneous image-guided biopsies to acquire bone samples for microbiological analysis remain limited. An expert panel convened by the Society of Academic Bone Radiologists developed and endorsed consensus statements on the various indications for percutaneous image-guided biopsies to standardize care and eliminate inconsistencies across institutions. The issued statements pertain to several commonly encountered clinical presentations of chronic osteomyelitis and were supported by a literature review. For most patients, MRI can help guide management and effectively rule out osteomyelitis when performed soon after presentation. Additionally, in the appropriate clinical setting, open wounds such as sinus tracts and ulcers, as well as joint fluid aspirates, can be used for microbiological culture to determine the causative microorganism. If MRI findings are positive, surgery is not needed, and alternative sites for microbiological culture are not available, then percutaneous image-guided biopsies can be performed. The expert panel recommends that antibiotics be avoided or discontinued for an optimal period of 2 weeks prior to a biopsy whenever possible. Patients with extensive necrotic decubitus ulcers or other surgical emergencies should not undergo percutaneous image-guided biopsies but rather should be admitted for surgical debridement and intraoperative cultures. Multidisciplinary discussion and approach are crucial to ensure optimal diagnosis and care of patients diagnosed with chronic osteomyelitis.

Musculoskeletal glomus tumor: a review of 218 lesions in 176 patients.

OBJECTIVE: To review the spectrum of clinical and imaging features of glomus tumor involving the musculoskeletal system including the typically solitary forms as well as the rarer multifocal forms (glomuvenous malformation and glomangiomatosis). MATERIALS AND METHODS: A retrospective review of our institutional pathology database from 1996 to 2023 identified 176 patients with 218 confirmed glomus tumors. Primary imaging studies included MRI (125), radiographs (100), clinical/intraoperative photos (77), and ultrasound (36). Lesions were divided into two groups: those that are typically solitary involving specific anatomic areas (finger, toe, soft tissue, coccyx, and bone), and those that are multifocal (glomuvenous malformation and glomangiomatosis). RESULTS: The finger was the most frequently involved anatomic location for the classic (sporadic) glomus tumor occurring in 51% of patients, 77% of which were women, with the nail plate involved in more of the 75% of cases. Sporadic lesions involving the skin, subcutaneous adipose tissue, and deep soft tissue were termed "soft tissue," and were identified in 39% of patients, 90% of which were in the extremities and in men in 81% of cases. The multifocal syndromic forms of glomus disease occurred in younger individuals and involved less than 6% of the study group. Patients with glomuvenous malformation presented early with predominantly cutaneous involvement, while those with glomangiomatosis present later, often with both superficial and deep involvement, and a high rate of local tumor recurrence. CONCLUSION: While glomus tumor is generally uncommon, it frequently involves the musculoskeletal extremities. Knowledge of the spectrum of characteristic locations and appearances will facilitate definitive diagnosis.

Pseudoendocrine sarcoma: a rare new entity with unique radiologic and pathologic/molecular characteristics.

Pseudoendocrine sarcoma is a rare, recently described intermediate grade sarcoma of uncertain phenotype that most commonly affects the paraspinal location in older patients with a distinctive endocrine/paraganglioma-like morphology and unique CTNNB1 point mutation. While these tumors appear as epithelial or even benign endocrine tumors, these lack markers for such and are highlighted by nuclear expression of beta-catenin. This case is the first among the previously reported only twenty-five cases of this entity, including one original series and a few case reports, to correlate the radiologic imaging with the pathologic features. Furthermore, this case illustrates the oldest-to-date patient with this unique location as a palpable painful chest wall/paraspinal location, with new morphologic observations and, finally, this is only the second case to have this specific CTNNB1 hotspot point mutation for this rare entity.

Fibroblastic and Myofibroblastic Soft-Tissue Tumors: Imaging Spectrum and Radiologic-Pathologic Correlation.

Fibroblastic and myofibroblastic tumors are a variable group of neoplasms ranging from benign to malignant. These lesions may affect patients of any age group but are more frequently encountered in the pediatric population. Patient clinical presentation depends on the location, growth pattern, adjacent soft-tissue involvement, and pathologic behavior of these neoplasms. In the 2020 update to the World Health Organization (WHO) classification system, these tumors are classified on the basis of their distinct biologic behavior, histomorphologic characteristics, and molecular profiles into four tumor categories: (a) benign (eg, fibrous hamartoma of infancy, nodular fasciitis, proliferative fasciitis, fibroma of the tendon sheath, calcifying aponeurotic fibroma); (b) intermediate, locally aggressive (eg, desmoid fibromatosis); (c) intermediate, rarely metastasizing (eg, dermatofibrosarcoma protuberans, myxoinflammatory fibroblastic sarcoma, low-grade myofibroblastic sarcoma, infantile fibrosarcoma); and (d) malignant (eg, sclerosing epithelioid fibrosarcomas; low-grade fibromyxoid sarcoma; myxofibrosarcoma; fibrosarcoma, not otherwise specified). Detection of various components of solid tumors at imaging can help in prediction of the presence of corresponding histopathologic variations, thus influencing diagnosis, prognosis, and treatment planning. For example, lesions with a greater myxoid matrix or necrotic components tend to show higher signal intensity on T2-weighted MR images, whereas lesions with hypercellularity and dense internal collagen content display low signal intensity. In addition, understanding the radiologic-pathologic correlation of soft-tissue tumors can help to increase the accuracy of percutaneous biopsy and allow unnecessary interventions to be avoided. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Imaging of spinal chordoma and benign notochordal cell tumor (BNCT) with radiologic pathologic correlation.

Benign notochordal cell tumor (BNCT) and chordoma are neoplasms of notochordal differentiation. BNCT represents notochordal rests, commonly an incidental lesion present in the spine in 19% of cadaveric specimens. BNCTs are often radiographically occult. CT of BNCT frequently reveals patchy sclerosis between areas of maintained underlying trabeculae. BNCT demonstrates marrow replacement on T1-weighted MR images with high signal intensity on T2-weighting. BNCTs are frequently smaller than 35 mm and lack significant enhancement, bone destruction, cortical permeation, or soft tissue components. Biopsy or surgical resection of BNCT is usually not warranted, although imaging surveillance may be indicated. Chordoma is a rare low-grade locally aggressive malignancy representing 1-4% of primary malignant bone tumors. Chordoma is most frequent between the ages of 50-60 years with a male predilection. Clinical symptoms, while nonspecific and location dependent, include back pain, numbness, myelopathy, and bowel/bladder incontinence. Unfortunately, lesions are often large at presentation owing to diagnosis delay. Imaging of chordoma shows variable mixtures of bone destruction and sclerosis, calcification (50-70% at CT) and large soft tissue components. MR imaging of chordoma reveals multilobulated areas of marrow replacement on T1-weighting and high signal intensity on T2-weighting reflecting the myxoid component within the lesion and areas of hemorrhage seen histologically. Treatment of chordoma is primarily surgical with prognosis related to resection extent. Unfortunately, complete resection is often not possible (21-75%) resulting in high local recurrence incidence (19-75%) and a 5-year survival rate of 45-86%. This article reviews and illustrates the clinical characteristics, pathologic features, imaging appearance spectrum, treatment, and prognosis of BNCT and spinal chordoma.

Ultrasonography of Superficial Soft-Tissue Masses: Society of Radiologists in Ultrasound Consensus Conference Statement.

The Society of Radiologists in Ultrasound convened a panel of specialists from radiology, orthopedic surgery, and pathology to arrive at a consensus regarding the management of superficial soft-tissue masses imaged with US. The recommendations in this statement are based on analysis of current literature and common practice strategies. This statement reviews and illustrates the US features of common superficial soft-tissue lesions that may manifest as a soft-tissue mass and suggests guidelines for subsequent management.

Staging and Classification of Primary Musculoskeletal Bone and Soft-Tissue Tumors According to the 2020 WHO Update, From the AJR Special Series on Cancer Staging.

Staging of primary musculoskeletal bone and soft-tissue tumors is most commonly performed using the AJCC and the Enneking or Musculoskeletal Tumor Society (MSTS) staging systems. Radiologic imaging is integral in achieving adequate musculoskeletal neoplastic staging by defining lesion extent and identifying regional lymph node involvement and distant metastatic disease. Additional important features in surgical planning, though not distinct components of the staging systems, include cortical involvement, joint invasion, and neurovascular encasement; these features are optimally evaluated by MRI. In 2020, the WHO updated the classification of primary musculoskeletal tumors of soft tissue and bone. The update reflects the continued explosion in identification of novel gene alterations in many bone and soft-tissue neoplasms. This growth in gene alteration identification has resulted in newly designated lesions, reclassification of lesion categories, and improved specificity of diagnosis. Although radiologists do not need to have a comprehensive knowledge of the pathologic details, a broad working understanding of the most recent update is important to aid accurate and timely diagnosis given that histologic grading is a component of all staging systems. By using a multidisciplinary approach for primary musculoskeletal neoplasms involving colleagues in pathology, orthopedic oncology, radiation oncology, and medical oncology, radiologists may promote improved diagnosis, treatment, and outcomes.

Lipoblastoma: computed tomographic and magnetic resonance imaging features correlate with tumor behavior and pathology.

BACKGROUND: Lipoblastoma is a rare benign neoplasm of immature fat cells in children. Imaging appearances are frequently complex, sometimes simulating liposarcoma. OBJECTIVE: To characterize features of lipoblastoma on MRI and CT in comparison with recurrence risk. MATERIALS AND METHODS: We identified cases via retrospective review of histopathology-proven lipoblastoma cases in a large referral database and a pediatric medical center. Two radiologists scored CT and MRI on the basis of lesion features. RESULTS: We included a total of 56 children (32 boys and 24 girls) with a mean age of 2.6 years (range 0.1-13 years). Extremity lesions were most common (27%), followed by neck (19%), gluteal region (18%), chest (14%) and mesentery (14%). Children most commonly presented with painless masses (73%), followed by dyspnea (9%), distension (9%) and pain (7%). Non-adipose soft-tissue components were identified on CT and MRI in 78% of cases. Significant (moderate or marked) septations were noted in 59% and enhancement in 35%. Compartmental invasion was present in 43% of cases. Of paraspinal cases, 38% involved the neural foramina or central canal. Lesion complexity did not significantly correlate with age. Recurrence was observed in 9% of cases and was significantly correlated with compartmental invasion (correlation: 0.303, P=0.009) and septation complexity (correlation: 0.227, P=0.038) on initial imaging. CONCLUSION: Although lipoblastoma is a fat-containing entity, many lesions demonstrate marked complexity and local infiltration that resemble liposarcoma, which is exceedingly rare in younger children. Compartmental invasion and thicker septations appear to confer greater risk of recurrence following resection.

Desmoplastic Fibroblastoma: An Uncommon Tumor With a Relatively Characteristic MRI Appearance.

OBJECTIVE. We undertook this study to determine the radiologic features of desmo-plastic fibroblastoma. MATERIALS AND METHODS. We reviewed available radiologic images for 29 pathologically confirmed desmoplastic fibroblastomas, including images from MRI, radiography, ultrasound (US), and CT. RESULTS. The patient population included 14 women and 15 men (mean age, 60 years; range, 23-96 years). Typically, lesions were oval or lobulated and relatively small (mean, 5.6 cm). In 14 of the 22 cases that included patient histories, lesions had grown slowly, with two eventually causing pain. The remaining eight were discovered incidentally. All lesions involved or were below the deep fascia. Lesions were well-defined and associated with muscle (45%), deep fascia (28%), joint (21%), or tendon (7%). MR images were available in 26 cases; 14 included unenhanced and contrast-enhanced studies. On MRI imaging all lesions were well-defined and adjacent to dense connective tissue. On T1-weighted images, lesions showed varying amounts of low and intermediate signal intensity similar to that of tendon and skeletal muscle, respectively. On fluid-sensitive images, lesions were more heterogeneous, generally showing a wider spectrum of decreased to intermediate signal intensity. On contrast-enhanced MR images, enhancement was characteristically peripheral and septal with patchy areas of homogeneity. In the 10 cases with radiographs, images showed negative findings or a nonmineralized mass. The 10 available ultrasound studies showed mixed echogenicity. In eight patients, unenhanced CT showed lesions having attenuation similar to that of skeletal muscle. CONCLUSION. Desmoplastic fibroblastoma is an uncommon neoplasm with a relatively characteristic MRI appearance.

Imaging of Soft-Tissue Musculoskeletal Masses: Fundamental Concepts.

Radiologic evaluation of musculoskeletal soft-tissue masses has changed dramatically with the continued improvements in imaging technology. The integration of advanced imaging has provided the radiologist with a wide range of assessment tools, but as with all powerful arsenals, selection and application of the appropriate imaging method can be problematic. Although the choices available for imaging evaluation of musculoskeletal masses have changed dramatically, the basic objectives of this assessment have remained constant: diagnosis and staging. The basic principles for evaluating musculoskeletal soft-tissue masses and achieving these objectives have not changed. This article addresses application of the current imaging methods to assessment of soft-tissue musculoskeletal masses, emphasizing fundamental concepts. We do not intend to provide a comprehensive review of imaging techniques, but rather to provide a useful review of the concepts needed to select the appropriate initial imaging method, magnetic resonance (MR) imaging field of view, MR imaging sequences, contrast material requirements, and rapid image acquisition techniques. We also address use of the new quantitative techniques of chemical shift and diffusion-weighted imaging. Finally, we review the current uses of computed tomography and ultrasonography. Although the choices available for imaging evaluation of musculoskeletal masses have changed dramatically within the past decade, appropriate application of the fundamental concepts of imaging will maximize the diagnostic utility of imaging examinations. ©RSNA, 2016.

Epitrochlear cat scratch disease: unique imaging features allowing differentiation from other soft tissue masses of the medial arm.

OBJECTIVE: Evaluate anatomic and imaging features of epitrochlear regional adenopathy secondary to cat scratch disease (CSD) to assist differentiation of CSD from other soft tissue masses at the elbow. MATERIALS AND METHODS: Retrospective review of 24 confirmed cases of CSD. Patient demographics, clinical presentation and radiographic (R; n = 10), CT (n = 3), ultrasound (US; n = 5), and MR (n = 21) images were reviewed. Lesion location, size, number of masses, and intrinsic characteristics on R/CT/US/MR and presence of soft tissue inflammatory changes or adjacent bone or joint involvement were established through the consensus interpretation by four musculoskeletal radiologists. RESULTS: The average patient age was 18.6 years. Mass location was anterior and superficial to the medial intermuscular septum (100 %) with the masses posterior or posteromedial to the basilic vein (92 %). Three or fewer lymph nodes were involved in 92 %. Masses were noncalcified with adjacent inflammatory change (R = 90 %, CT = 100 %). US showed hypoechoic soft tissue echogenicity masses with defined to minimally irregular margins (80 %) and preserved central hilar hypervascularity on Doppler (100 % of cases). On MR, masses were T1 isointense (62 %), T2 isointense (54 %), intermediate signal on T2 images with fat suppression (55 %), and had perilesional inflammatory changes (95 %), perilesional fluid collections (38 %), adjacent muscle edema (81 %), hyperintense cental hilar vascular enhancement (65 %) and occasional preserved central hilar fat (14 %). CONCLUSION: Cat scratch disease is suggested by the characteristic location of a medial epitrochlear mass superficial to the brachial fascia and posterior to the basilic vein with surrounding inflammatory changes and preservation of hilar vascular architecture, hilar enhancement and occasional hilar fat.

Soft-tissue myxomatous lesions: review of salient imaging features with pathologic comparison.

Myxoid soft-tissue lesions are a heterogeneous group of benign and malignant mesenchymal tumors with an abundance of extracellular mucoid material. These lesions may mimic cysts on radiologic evaluation because of the high water content, and histopathologic features also overlap. Benign myxoid lesions include intramuscular myxoma, synovial cyst, bursa, ganglion, and benign peripheral nerve sheath tumor, including neurofibroma and schwannoma. Malignant entities include myxoid liposarcoma, myxoid leiomyosarcoma, myxoid chondrosarcoma, ossifying fibromyxoid tumor, and myxofibrosarcoma. Some syndromes are associated with myxoid soft-tissue lesions, such as Mazabraud syndrome in patients with soft-tissue myxomas and fibrous dysplasia. Certain discriminating features, such as intralesional fat in a myxoid liposarcoma, perilesional edema and a rim of fat in soft-tissue myxoma, and the swirled T2-weighted signal intensity and enhancement pattern of aggressive angiomyxoma, assist the radiologist in differentiating these lesions. The presence of an internal chondroid matrix or incomplete peripheral ossification may suggest myxoid chondrosarcoma or ossifying fibromyxoid tumor, respectively. The entering-and-exiting-nerve sign is suggestive of a peripheral nerve sheath tumor. Communication with a joint or tendon sheath and peripheral enhancement may indicate a ganglion or synovial cyst. This article (a) reviews the magnetic resonance, computed tomographic, and ultrasonographic imaging characteristics of soft-tissue myxomatous lesions, emphasizing imaging findings that can help differentiate benign and malignant lesions; (b) presents differential diagnoses; and (c) provides pathologic correlation.

From the radiologic pathology archives imaging of osteonecrosis: radiologic-pathologic correlation.

Osteonecrosis is common and represents loss of blood supply to a region of bone. Common sites affected include the femoral head, humeral head, knee, femoral/tibial metadiaphysis, scaphoid, lunate, and talus. Symptomatic femoral head osteonecrosis accounts for 10,000-20,000 new cases annually in the United States. In contradistinction, metadiaphyseal osteonecrosis is often occult and asymptomatic. There are numerous causes of osteonecrosis most commonly related to trauma, corticosteroids, and idiopathic. Imaging of osteonecrosis is frequently diagnostic with a serpentine rim of sclerosis on radiographs, photopenia in early disease at bone scintigraphy, and maintained yellow marrow at MR imaging with a serpentine rim of high signal intensity (double-line sign) on images obtained with long repetition time sequences. These radiologic features correspond to the underlying pathology of osseous response to wall off the osteonecrotic process and attempts at repair with vascularized granulation tissue at the reactive interface. The long-term clinical importance of epiphyseal osteonecrosis is almost exclusively based on the likelihood of overlying articular collapse. MR imaging is generally considered the most sensitive and specific imaging modality both for early diagnosis and identifying features that increase the possibility of this complication. Treatment subsequent to articular collapse and development of secondary osteoarthritis typically requires reconstructive surgery. Malignant transformation of osteonecrosis is rare and almost exclusively associated with metadiaphyseal lesions. Imaging features of this dire sequela include aggressive bone destruction about the lesion margin, cortical involvement, and an associated soft-tissue mass. Recognizing the appearance of osteonecrosis, which reflects the underlying pathology, improves radiologic assessment and is important to guide optimal patient management.

Fluid collections in amputations are not indicative or predictive of infection.

BACKGROUND: In the acute postoperative period, fluid collections are common in lower extremity amputations. Whether these fluid collections increase the risk of infection is unknown. QUESTIONS/PURPOSES: The purposes of this study were to determine (1) the percentage of patients who develop postoperative fluid collections in posttraumatic amputations and the natural course of the collection; (2) whether patients who develop these collections are at increased risk for infection; and to ask (3) are there objective clinical or radiologic signs that are associated with likelihood of infection when a fluid collection is present? METHODS: We performed a review of all 300 patients injured in combat operations who sustained at least one major lower extremity amputation (at or proximal to the tibiotalar joint) and were treated definitively at our institution between March 2005 and April 2009. We segregated the groups based on whether cross-sectional imaging was performed less than 3 months (early group) after closure, greater than 3 months (late group) after closure, or not at all (control group, baseline frequency of infection). Our primary study cohort where those patients with a fluid collection in the first three months. The clinical course was reviewed and the primary outcome was a return to the operating room for irrigation and débridement with positive cultures. For those patients with cross-sectional imaging, we also collected objective clinical parameters within 24 hours of the scan (white blood cell count, maximum temperature, presence of bacteremia, tachycardia, oxygen desaturation), extremity examination (presence of erythema, warmth, and/or drainage), and characteristics of the fluid collections seen (size of the fluid collection, enhancement, complexity (simple versus loculated), surrounding edema, skin changes, tract formation, presence of air, and changes within the bone itself). The presence of a fluid collection on imaging was analyzed to determine whether it was associated with infection. We further analyzed clinical parameters, objective physical examination findings at the extremity, and characteristics of the fluid collection to determine if there were other parameters associated with infection. RESULTS: Over half (55%) of the limbs demonstrated fluid collection in the early postoperative period and the prevalence decreased in the late group (11%; p = 0.001). There was no association between the presence of a fluid collection and infection. However, there was an association between objective clinical signs at the extremity (erythema and/or drainage) and infection (p < 0.001) in our primary study cohort. CONCLUSIONS: Fluid collections are common in combat-related amputations in the immediate postoperative period and become smaller and less frequent over time. In the absence of extremity erythema and wound drainage, imaging of a residual limb to evaluate for the presence of a fluid collection appears to be of little clinical use.

Sclerosing variant of well-differentiated liposarcoma: relative prevalence and spectrum of CT and MRI features.

OBJECTIVE: The purpose of this study was to determine the relative prevalence of the sclerosing variant of well-differentiated liposarcoma at one institution and to elucidate the CT and MRI characteristics of this subtype of well-differentiated liposarcoma. MATERIALS AND METHODS: A retrospective computerized search was conducted to calculate the relative prevalence of the sclerosing variant of well-differentiated liposarcoma among all well-differentiated liposarcoma subtypes at one institution. The MRI and CT features of a total of 19 cases of pathologically proven sclerosing variant of well-differentiated liposarcoma were evaluated (seven identified from the study institution database and 12 cases contributed by other institutions). RESULTS: The cases of a total of 36 patients with well-differentiated liposarcoma were identified in the pathology database; six (17%) cases had evidence of dedifferentiation. Seven (19%) cases of sclerosing variant of well-differentiated liposarcoma were identified. Of these, three (43%) had evidence of dedifferentiation. On images, the sclerosing variant of well-differentiated liposarcoma typically presented as a large (average, 16.6 cm) well-circumscribed heterogeneous mass most commonly situated in the retroperitoneum (58%). Sixteen of the 19 tumors evaluated (84%) had predominantly well-circumscribed margins. Tumor composition ranged from predominantly fatty to entirely devoid of macroscopic fat; only three (16%) were composed of more than 75% fat. Variable amounts of nonlipomatous elements were identified in all cases. Enhancement of these elements was evident at CT or MRI in all 14 cases in which enhancement could be reliably assessed. CONCLUSION: The sclerosing variant of well-differentiated liposarcoma should be included in the differential diagnosis of any well-circumscribed lipomatous mass containing variable amounts of nonlipomatous elements, particularly when located in the retroperitoneum. Unlike other subtypes of well-differentiated liposarcoma, the sclerosing variant is less likely to be composed predominantly of fat and may be associated with an increased propensity for dedifferentiation.

From the radiologic pathology archives: ewing sarcoma family of tumors: radiologic-pathologic correlation.

The Ewing sarcoma family of tumors includes osseous Ewing sarcoma, extraskeletal Ewing sarcoma, primitive neuroectodermal tumor, and Askin tumor. They share a karyotype abnormality with translocation involving chromosomes 11 and 22. Histologically, these lesions demonstrate crowded sheets of small round blue cells. Imaging features of osseous Ewing sarcoma often suggest the diagnosis, with aggressive long-bone destruction in the metadiaphysis of an adolescent or young adult and an associated soft-tissue mass. Focal areas of cortical destruction are frequent, allowing continuity between the intraosseous and extraosseous components. This continuity is also commonly seen as subtle channels extending through the cortex at computed tomography or magnetic resonance (MR) imaging, a finding that reflects the underlying pathologic appearance. Extraskeletal Ewing sarcoma commonly demonstrates a nonspecific radiologic appearance of a large soft-tissue mass affecting the paraspinal region or lower extremity. Askin tumor represents extraskeletal Ewing sarcoma involving the chest wall. Imaging typically reveals a large pleural-based mass and associated pleural effusion. Treatment of these tumors is usually a combination of neoadjuvant chemotherapy followed by surgical resection, which may be supplemented with radiation therapy. Imaging, particularly MR, is also vital to evaluate response to neoadjuvant therapy, direct surgical resection, and detect local recurrence or metastatic disease.

Chondrosarcoma: A Diagnostic Imager's Guide to Decision Making and Patient Management.

Chondrosarcoma is the third most common primary malignant bone tumor. Currently, outcomes are based largely on a histologic grading scale described by the World Health Organization (WHO) Classification of Bone Tumors (2002). This classification scheme possesses evident utility in the evaluation and management of higher grade tumors, but it is often unable to distinguish enchondromas from low-grade chondrosarcomas. This is problematic when low-grade lesions that are histologically similar to enchondromas demonstrate aggressive imaging features. Because histologic classification alone often belies the clinical significance of chondroid lesions, it is also important to consider radiologic staging as part of the clinical decision making process. This article focuses on medical decision support considerations relevant when confronted with this challenging subset of chondroid tumors, particularly differentiating the benign enchondroma from its notorious relative, the low-grade chondrosarcoma. In doing so, we present a review of the salient imaging features and discuss key differentiating characteristics.

Posttraumatic cysts after pediatric fracture.

BACKGROUND: Pediatric postfracture cystic bone lesions are most commonly found on routine follow-up radiographs of distal radius fractures. After their discovery, there is often a discussion of the need for further radiologic imaging or operative intervention. METHODS: We present 3 cases in which all the 3 pediatric patients had a history of a healing fracture and had the lesions diagnosed incidentally on average 3 months after initial injury. RESULTS: These similar cases demonstrate the nearly identical radiographic characteristics of postfracture cystic lesions of the distal radius. The radiographs consistently demonstrate a well-circumscribed lytic lesion without surrounding sclerosis (geographic 1B) within the elevated periosteum of the healing fracture. These lesions appeared to sit on top of the previous cortex without causing any erosion or having any other aggressive characteristics. All of the lesions were consistent with adipose tissue on all sequence including T1, T2, and fat-suppressed T1-weighted imaging. CONCLUSIONS: Although postfracture pediatric cysts are apparently rare, we feel that there is sufficient literature to support that there is no longer any need for advanced imaging modalities to diagnose these lesions in the setting of an appropriate history without confounding variables and classic radiographic appearance. Biopsy, in particular, is decidedly unnecessary, unless the lesion progresses on subsequent radiographs or demonstrates more overtly aggressive initial features. CLINICAL RELEVANCE: This will allow for faster diagnosis with substantially less burden on the health care system and decreased the stress that is placed on the patients and families involved by requiring magnetic resonance imaging with or without conscious sedation in order to make the final diagnosis. LEVEL OF EVIDENCE: IV-case series.

Bone Tumor Risk Stratification and Management System: A Consensus Guideline from the ACR Bone Reporting and Data System Committee.

The assessment and subsequent management of a potentially neoplastic bone lesion seen at diagnostic radiography is often complicated by diagnostic uncertainty and inconsistent management recommendations. Appropriate clinical management should be directed by risk of malignancy. Herein, the ACR-sponsored Bone Reporting and Data System (Bone-RADS) Committee, consisting of academic leaders in the fields of musculoskeletal oncology imaging and orthopedic oncology, presents the novel Bone-RADS scoring system to aid in risk assignment and provide risk-aligned management suggestions. When viewed in the proper clinical context, a newly identified bone lesion can be risk stratified as having very low, low, intermediate, or high risk of malignancy. Radiographic features predictive of risk are reviewed include margination, pattern of periosteal reaction, depth of endosteal erosion, pathological fracture, and extra-osseous soft tissue mass. Other radiographic features predictive of histopathology are also briefly discussed. To apply the Bone-RADS scoring system to a potentially neoplastic bone lesion, radiographic features predictive of risk are each given a point value. Point values are summed to yield a point total, which can be translated to a Bone-RADS score (1-4) with corresponding risk assignment (very low, low, intermediate, high). For each score, evidence-based and best practice consensus management suggestions are outlined. Examples of each Bone-RADS scores are presented, and a standardized diagnostic radiography report template is provided.