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.

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.

Diagnostic errors in musculoskeletal oncology and possible mitigation strategies.

The objective of this paper is to explore sources of diagnostic error in musculoskeletal oncology and potential strategies for mitigating them using case examples. As musculoskeletal tumors are often obvious, the diagnostic errors in musculoskeletal oncology are frequently cognitive. In our experience, the most encountered cognitive biases in musculoskeletal oncologic imaging are as follows: (1) anchoring bias, (2) premature closure, (3) hindsight bias, (4) availability bias, and (5) alliterative bias. Anchoring bias results from failing to adjust an early impression despite receiving additional contrary information. Premature closure is the cognitive equivalent of "satisfaction of search." Hindsight bias occurs when we retrospectively overestimate the likelihood of correctly interpreting the examination prospectively. In availability bias, the radiologist judges the probability of a diagnosis based on which diagnosis is most easily recalled. Finally, alliterative bias occurs when a prior radiologist's impression overly influences the diagnostic thinking of another radiologist on a subsequent exam. In addition to cognitive biases, it is also important for radiologists to acknowledge their feelings when making a diagnosis to recognize positive and negative impact of affect on decision making. While errors decrease with radiologist experience, the lack of application of medical knowledge is often the primary source of error rather than a deficiency of knowledge, emphasizing the need to foster clinical reasoning skills and assist cognition. Possible solutions for reducing error exist at both the individual and the system level and include (1) improvement in knowledge and experience, (2) improvement in clinical reasoning and decision-making skills, and (3) improvement in assisting cognition.

Rib hyperostosis: a benign entity with suspicious imaging features.

Rib hyperostosis has previously been described in conjunction with disorders causing excessive vertebral ossification due to osseous bridging across the costovertebral joint, such as in diffuse idiopathic skeletal hyperostosis. Hyperostosis is believed to be a reactive process due to altered forces across the affected rib as bridging osteophytes decrease mobility at the respective costovertebral joint. The imaging characteristics of rib hyperostosis can be highly suspicious for malignancy. We share 2 cases of biopsy-proven benign rib hyperostosis with imaging across multiple modalities in hopes of increasing awareness of this entity and its imaging characteristics. In the first case, a 62-year-old female without history of malignancy underwent rib biopsy after bone scintigraphy demonstrated intense radiotracer uptake along a posteromedial rib. In the second case, a 66-year-old male with history of recurrent prostate cancer underwent rib biopsy after interval development of intense radiotracer uptake on bone scintigraphy along a posteromedial rib, new compared to 6 months prior. Both cases were seen in the setting of osseous bridging at the respective costovertebral joint. Imaging findings include contiguous radiotracer uptake on bone scintigraphy confined to the rib and respective costovertebral joint, cortical bone thickening with osseous excrescence at the costovertebral joint on radiographic and cross-sectional imaging, and increased osseous edema-like change, postcontrast enhancement, and surrounding soft tissue edema on magnetic resonance imaging. By increasing awareness to these imaging features, we hope to improve diagnostic confidence and decrease unnecessary, expensive, and sometimes invasive workup for future patients.

Novel fusion sarcomas including targetable NTRK and ALK.

BACKGROUND: Challenging emerging entities with distinctive molecular signatures may benefit from algorithms for diagnostic work-up. METHODS: Fusion sarcomas (2020-2021, during pandemic) were diagnosed by clinicoradiology, morphology, phenotype, and next-generation sequencing (NGS). RESULTS: Six fusion sarcomas in two males and four females involved the chest-wall, neck, or extremities; ages ranged 2-73, median 18 years. Sizes ranged 5.3-25.0, median 9.1 cm. These include high grade 1) TPR-NTRK1 of proximal femur with a larger rounded soft tissue mass, previously considered osteosarcoma yet without convincing tumor matrix. A pathologic fracture necessitated emergency hemipelvectomy (NED) and 2) novel KANK1-NTRK2 sarcoma of bone and soft tissue with spindled pleomorphic to epithelioid features (AWD metastases). 3) Novel ERC1-ALK unaligned fusion, a low grade infiltrative deep soft tissue hand sarcoma with prominent-vascularity, myopericytoid/lipofibromatosis-like ovoid cells, and collagenized stroma, was successfully treated with ALK-inhibitor (Crizotinib), avoiding amputation. These NTRK and ALK tumors variably express S100 and CD34 and were negative for SOX10. 4) and 5) CIC-DUX4 round cell tumors (rapid metastases/demise), one with COVID superinfection, were previously treated as Ewing sarcoma. These demonstrated mild pleomorphism and necrosis, variable myxoid change and CD99 reactivity, and a distinctive dot-like-Golgi WT1 immunostaining pattern. 6) A chest wall/thoracic round cell sarcoma, focal CD34/ keratins/CK7, revealed nuclear-STAT6, STAT6-NAB2 by NGS, confirming malignant solitary fibrous tumor, intermediate-risk-stratification (AWD metastases). CONCLUSIONS: Recent fusion sarcomas include new KANK1-NTRK2 and ERC1-ALK, the latter successfully treated by targeted-therapy. ALK/NTRK fusion partners TPR and KANK1 suggest unusual high-grade morphology/behavior. Clinicoradiologic, morphologic, and phenotypic algorithms can prompt molecular-targeted immunostains or NGS for final classification and promising inhibitor therapy.

Cervical Dystonia Caused by Chronic Nonunion C2 Fracture: A Case Report.

Chronic nonunion cervical fracture leading to cervical dystonia (CD) is very rare. This study reports a 72-year-old man who presented with 9-month history of progressively worsening neck tilting, neck tightness, neck pain, headache, and difficulty with swallowing. The patient was referred to speech therapy and confirmed to have dysphagia on modified barium swallow study. A cervical spine radiograph showed a chronic C2 nonunion fracture. Subsequent cervical spine magnetic resonance imaging confirmed chronic C2 nonunion fracture with kyphotic deformity of the cervical canal with associated cord compression at C1-C2 and severe central canal stenosis. Needle electromyography revealed dystonic or spasmodic neck muscles, consistent with diagnosis of CD. Botulinum toxin injection resulted in marked clinical improvement. The patient finally underwent occipital to C4 posterior segmental fusion. No recurrence of CD had occurred 12 months after botulinum toxin injection and surgery, which supports the conclusion that chronic C2 nonunion fracture is most likely responsible for CD in this case. The authors suggest that all patients with CD receive dysphagia evaluation and more importantly cervical spine imaging to rule out chronic C2 nonunion fracture.

Scurvy: a rare case in an adult.

A 69-year-old man presented with unilateral calf pain, swelling, and erythematous rash. He was initially treated with antibiotics for suspected cellulitis. A venous duplex ultrasound, performed to exclude deep venous thrombosis, revealed multiple heterogeneous hypoechoic foci of unknown etiology throughout the calf musculature. His condition did not improve with antibiotics, instead progressing to a necrotic ulcer along the medial malleolus. Clinical suspicion of vascular insufficiency or vasculitis prompted an extensive imaging work-up. CT and MRI revealed the intramuscular abnormalities observed on previous ultrasound represented foci of intramuscular hemorrhage. Marrow signal abnormality was also noted in the proximal tibia. A punch biopsy of the skin rash ultimately demonstrated distorted hair follicles with perifollicular inflammation and hemorrhage concerning for scurvy. The diagnosis was confirmed by low vitamin C levels and dietary history. A resurgence of scurvy has occurred in the pediatric population in recent years. However, this diagnosis remains uncommon in adults, with limited reports of the potential advanced imaging findings in the current literature.

Adventitial Cystic Disease of the Radial Artery.

Upper extremity adventitial cystic disease is rare, but the characteristic findings of this lesion should be known to the hand surgeon and used to guide treatment. We present a case of a young adult male who developed a painless mass in his distal forearm. Diagnostic imaging workup revealed a cystic mass that extended within and encased the radial artery. Both MRI and direct intraoperative visualization confirmed the presence of a stalk connecting the intra-mural radial artery mass to the radiocarpal joint. The mass and stalk were excised en bloc with fenestration of the volar capsule to prevent recurrence. This case demonstrates a less common example of upper extremity adventitial cystic disease and supports the articular theory of origin of these lesions. When surgical excision is performed, an attempt should be made to identify and excise the articular stalk in an effort to minimize risk of recurrence.

Rapidly Progressive Osteoarthritis: a Review of the Clinical and Radiologic Presentation.

PURPOSE OF REVIEW: The purpose of this paper is to review the distinct clinical and radiographic features that may lead to prompt diagnosis of rapidly progressive osteoarthritis (RPOA) and thus obviate unnecessary and costly diagnostic workup. RECENT FINDINGS: RPOA is uncommon but is more frequently seen in practice because of the aging population. RPOA is a destructive arthropathy that occurs most commonly in elderly women but can also be seen in patients that have sustained trauma. The dramatic radiologic manifestations of RPOA can lead to diagnostic confusion with other arthropathies, infection, and osteonecrosis. RPOA was originally described in the hip but may also involve the shoulder. The etiology of RPOA is not well understood, but subchondral fracture probably plays a role in the development of dramatic destruction of the joint that is seen in affected patients. Early diagnosis may reduce the complexity of surgical management. RPOA is an uncommon condition that occurs most frequently in elderly woman or in patients who have sustained trauma. Prompt recognition of the clinical and radiologic features of this arthropathy can reduce unnecessary diagnostic workup and complexity of surgical intervention.

Outcomes in diabetic foot ulcer patients with isolated T2 marrow signal abnormality in the underlying bone: should the diagnosis of "osteitis" be changed to "early osteomyelitis"?

OBJECTIVE: To evaluate the variability of clinical treatment and outcomes based on reporting of diabetic foot ulcer MRI findings of adjacent marrow T2 hyperintensity with normal T1 signal. MATERIALS AND METHODS: A retrospective review was conducted of 46 MRI examinations evaluating diabetic foot ulcers that demonstrated normal T1 marrow signal, but T2 marrow hyperintensity deep to the ulcer. The cohort was divided based on MRI report impressions into three groups; "osteitis without osteomyelitis" (OW), "osteitis but cannot exclude early osteomyelitis" (OCEO) and "early osteomyelitis" (EO). Patient demographics (age, gender) and accessory MRI findings of ulcer and sinus tract depth were recorded. Initial clinical assessment and medical treatment (route and duration of antibiotics), healing versus disease progression and histology or microbiology results were recorded. RESULTS: The isolated marrow T2 signal hyperintensity was reported as OW in 12 patients, OCEO in 18, and EO in 16. No statistical difference in clinical assessment was demonstrated between the OW, OCEO, and EO groups. Pathological condition was available in 15 patients within 0-7 days (mean 2.4 days) of the MRI examination, with 14 (93%) of these positive for osteomyelitis by histopathology or positive cultures. Initial diagnosis of or progression to osteomyelitis was shown in 28 patients (61%). CONCLUSION: Treatment of suspected osteomyelitis is heavily determined by clinical factors. Patients who initially demonstrate only T2 marrow signal abnormality under a diabetic ulcer are eventually diagnosed as osteomyelitis in 61% of cases and deserve aggressive treatment as early osteomyelitis when meeting clinical parameters.

Subscapularis function after total shoulder arthroplasty: electromyography, ultrasound, and clinical correlation.

BACKGROUND: The literature lacks electromyographic (EMG) examination of subscapularis function in the postoperative period after total shoulder arthroplasty (TSA). The primary purpose of this study was to document EMG activity of the subscapularis after TSA and to correlate it with clinical and ultrasound findings. METHODS: The study included 30 patients who were at least 1 year (average, 2.1 years) from surgery, status post TSA approached through a standard subscapularis tenotomy. Patients returned for a physical examination, ultrasound evaluation, and EMG evaluation. Patients also completed postoperative surveys: the American Shoulder and Elbow Surgeons questionnaire, the Simple Shoulder Test, and the 12-Item Short Form Health Survey. RESULTS: The American Shoulder and Elbow Surgeons, Simple Shoulder Test, and physical 12-Item Short Form Health Survey scores improved from preoperatively to postoperatively, respectively, 45.3 to 76.8 (P = .0002), 3.9 to 9.0 (P < .0001), and 33.9 to 42.8 (P = .017). Six patients had a positive lift-off test result, and the belly-press test result was negative in all patients. Two patients had a subscapularis rupture on ultrasound. The postoperative EMG finding was normal in 15 patients; in the other 15 patients, there was evidence of chronic denervation with reinnervation changes: 30% subscapularis, 27% infraspinatus, 20% supraspinatus, 20% teres minor, and 13% rhomboids. CONCLUSIONS: This is the first study using a comparison EMG evaluation to document subscapularis function after TSA. EMG evaluation showed that active denervation of the subscapularis was not evident in any patient at least 1 year after TSA. However, in half of the patients, there was evidence of chronicdenervation and reinnervation changes across 5 muscle groups. We theorize that surgical exposure, traction, and the use of interscalene regional anesthesia may contribute to these unexpected EMG results.

A young male runner with a posterior knee mass--not just your typical Baker's cyst.

We present the case of a 28-year-old man with a growing mass in his right popliteal fossa causing pain on exertion. The differential diagnosis included Baker's cyst, entrapment syndrome of the popliteal artery, as well as a benign or malignant neoplasm. An ultrasound was non-specific. Follow-up MRI of the knee demonstrated cystic adventitial disease (CAD). With only about 500 cases reported in the literature since its discovery in 1947, CAD is a rare entity. The disease is characterised by mucinous or gelatinous cysts in the arterial or venous adventitia. The disease is predominantly seen in the popliteal artery and typically affects otherwise healthy males in the fourth to fifth decade of life. It presents clinically as intermittent exertional claudication. Examination of our case and a review of the literature will highlight the importance of considering CAD in patients who report of a popliteal mass and intermittent claudication.

MR imaging assessment of arthritis of the knee.

The magnetic resonance (MR) imaging presentations of arthritis of the knee are important for radiologists to recognize because these disorders are often clinically unsuspected. When they are known or clinically suspected, knowledge of imaging features allows for the confirmation and characterization of the extent of disease. This article reviews the fundamental MR imaging manifestations of rheumatologic disorders of the knee and their presentation in specific arthropathies.

Arthritis mimicking sports-related injuries.

Arthritis, including inflammatory, crystal deposition, and synovial proliferative disorders, may mimic sports injury. The purpose of this article is to review the clinical and radiologic findings of arthropathies that can present in athletes and be confused with internal derangement.

Primary osseous tumors of the spine.

Primary osseous spinal tumors are relatively rare in comparison with metastatic disease, myeloma, and lymphoma. Despite their rarity, the interpreting radiologist must be aware of the typical imaging features to provide appropriate diagnosis for guidance of clinical management. The age of occurrence, distribution longitudinally in the spine, and distribution axially within the vertebra combined with typical imaging appearances can help indicate the correct diagnosis. This article reviews the diagnostic features of benign and malignant primary bone spinal tumors.

False-positive PET/CT for lymphoma recurrence secondary to Langerhans cell histiocytosis.

A 28-year-old man with a history of Hodgkin lymphoma that was intensely [F-18]fluoro-2-deoxy-D-glucose-avid at diagnosis had achieved complete remission following appropriate therapy. On surveillance positron emission tomography/computed tomography (CT), new, intensely [F-18]fluoro-2-deoxy-D-glucose-avid lesions (lytic on CT) were seen within the vertebral body of C7, left scapula, and right glenoid. The findings of a biopsy revealed these lesions to be Langerhans cell histiocytosis. Langerhans cell histiocytosis arising in the context of lymphoma is a well-documented phenomenon, and its appearance on positron emission tomography/CT cannot be conclusively distinguished from lymphoma recurrence. This manuscript emphasizes the necessity of biopsy to ensure correct diagnosis and subsequent correct therapy.

Comparison of standard two-dimensional and three-dimensional corrected glenoid version measurements.

HYPOTHESIS: There is concern regarding the accuracy of 2-dimensional (2D) computed tomography (CT) for measuring glenoid version. Three-dimensional (3D) CT scan reconstructions can properly orient the glenoid to the plane of the scapula and have been reported to accurately measure glenoid version in cadaver models. We hypothesized that glenoid version measured by correcting 2D CT scans to the plane of the scapula by 3D reconstruction would be significantly different compared with standard 2D CT scan measurement of the glenoid in a clinical patient population. MATERIALS AND METHODS: Thirty-four patients underwent dedicated axial 2D CT scan of the shoulder with 3D reconstruction. The 2D glenoid version was measured on unmodified midglenoid axial cuts, and the 3D glenoid version measurement was corrected to be perpendicular to the plane of the scapula and then measured in the axial plane. Three observers repeated each measurement on 2 different days. RESULTS: The difference between the overall average 2D and 3D measurements was not statistically significant (P = .45). In individual scapulae, 35% of 2D measurements were 5° to 10° different and 12% were greater than 10° different from their corresponding 3D-corrected CT measurement (P < .001 to P = .045). Reproducibility of both 2D and 3D-corrected measurements was good. DISCUSSION: Although 2D and 3D corrected methods showed a high degree of both intraobserver and interobserver reliability in this series, axial 2D images without correction were 5 to 15 degrees different than their 3D-corrected counterparts in 47% of all measurements. Correcting 2D glenoid version by 3D reconstruction to the transverse plane perpendicular to the scapular body allows for an accurate assessment of glenoid version in spite of positioning differences and results in increased accuracy while maintaining high reliability. CONCLUSIONS: Owing to the variability in scapular position, the axial 2D CT scan measurement was significantly different from 3D-corrected measurement of glenoid version. Averaging the version measurements across patients did not reflect this finding.

MRI manifestations of bowler's thumb.

Bowler's thumb is a rare perineural fibrosis involving the ulnar digital nerve of the thumb. Affected patients present with pain, neuropathy, and mass lesion. The condition is caused by chronic repetitive impaction of the ulnar soft tissues of the thumb against the thumbhole of a bowling ball. In our case, MRI showed decreased signal intensity on both T1- and T2-weighted images surrounding an enlarged ulnar digital nerve of the thumb. The findings can be confused with giant-cell tumor of the tendon sheath or peripheral-nerve-sheath tumor.

Improved differentiation of benign osteochondromas from secondary chondrosarcomas with standardized measurement of cartilage cap at CT and MR imaging.

PURPOSE: To validate a technique for reproducible measurement of the osteochondroma cartilage cap with computed tomography (CT) and magnetic resonance (MR) imaging and to reevaluate the correlation of the thickness of the cartilage cap with pathologic findings to improve noninvasive differentiation of benign osteochondromas from secondary chondrosarcomas. MATERIALS AND METHODS: The institutional review board approved the study and waived the need for informed consent. HIPAA compliance was maintained. After validation of the measurement technique, 101 pathologically confirmed osteochondromas were retrospectively reviewed. Patient demographic data, histologic diagnosis, and chondrosarcoma grade were recorded. Two musculoskeletal radiologists used a standardized technique to independently measure the thicknesses of the cartilage caps on CT and MR images; these measurements were compared for interobserver agreement. Agreement between measurements with CT and MR imaging was also evaluated, as were the sensitivity and specificity of both modalities for differentiation of osteochondromas from chondrosarcomas. RESULTS: Evaluated were 67 benign osteochondromas (from 49 male patients and 18 female patients; mean age, 23.4 years) and 34 secondary chondrosarcomas (from 27 male patients and seven female patients; mean age, 33.2 years). On the basis of the proposed measuring technique, there was 88% interobserver measurement agreement with MR imaging (95% confidence interval [CI]: 80%, 94%) and 93% with CT (95% CI: 84%, 98%). The median difference between measurements of cap thickness at CT and MR imaging was 0 cm (25th and 75th percentiles, -3 mm and 1 mm, respectively). With 2 cm used as a cutoff for distinguishing benign osteochondromas from chondrosarcomas, the sensitivities and specificities were 100% and 98% for MR imaging and 100% and 95% for CT, respectively. CONCLUSION: The proposed measuring technique allows accurate and reproducible measurement of cartilage cap thickness with both CT and MR imaging. Cap thickness of 2 cm or greater strongly indicated secondary chondrosarcomas.

Two-dimensional glenoid version measurements vary with coronal and sagittal scapular rotation.

BACKGROUND: Accurate analysis of osseous glenoid morphology is important in treating glenohumeral arthritis and instability. Two-dimensional computed tomography scans are used to evaluate glenoid alignment. Accuracy of this method is dependent on the angle of axial reconstruction in relation to the position of the scapula. The purpose of this study was to investigate the effect of scapular rotation in the coronal and sagittal planes on glenoid version as measured on two-dimensional images. METHODS: Computer-generated three-dimensional models of scapulae from computed tomography scans of thirty-six shoulders in whole-body cadavers were generated. The anatomic geometry of these models had been previously validated. The position of the scapulae relative to the gantry was determined. The three-dimensional models were rotated in 1 degree increments in the coronal and sagittal planes. Glenoid version was measured on two-dimensional images for each of the rotation increments. Version variability at each rotation increment was calculated. RESULTS: The anatomic glenoid version (independent of the resting position of the scapula) was an average (and standard deviation) of 2.0 degrees +/- 3.8 degrees of retroversion. The average difference between anatomic glenoid version and clinical glenoid version (depending on the position of the scapula on the original computed tomography axial images) was 6.9 degrees +/- 5.6 degrees (range, 0.1 degrees to 22.5 degrees). Version variability with coronal or sagittal rotation was significant for all degrees of rotation (p < 0.0001). Scapular abduction had the greatest effect on version variation and resulted in 0.42 degrees of relative anteversion for every 1 degree of abduction in the coronal plane. In the sagittal plane, internal rotation resulted in relative anteversion. CONCLUSIONS: Any malalignment of > or = 1 degree of the scapula in the coronal or sagittal plane will create inaccuracies in measuring glenoid version. The plane of axial reconstruction should be aligned with the scapula when two-dimensional computed tomography images are used to measure glenoid version. These findings support the use of three-dimensional models to evaluate glenoid version.