Skeletal Radiol Research Articles

DIAPHRAGM DYSFUNCTION: A SEQUELA OF SARS-COV-2 INFECTION

TOPIC: Pulmonary Manifestations of Systemic Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: The clinical spectrum of SARS-CoV-2 infection varies from asymptomatic infection to critical illness and death. Many patients report persistent dyspnea and fatigue for months following their acute illness. SARS-CoV-2 has an affinity for neural and muscular tissue which may lead to persistent dyspnea and fatigue among the survivors. Here, we discuss a case of diaphragmatic dysfunction due to COVID-19 infection contributing to persistent dyspnea. CASE PRESENTATION: A 49-year-old male smoker with medical history notable only for COVID-19 infection 5 months prior, was admitted for worsening shortness of breath associated with right sided chest discomfort and cough for several months. On evaluation, he was found to be tachypneic and tachycardic with mild hypoxia.Four weeks prior, he was hospitalized with similar complaints and was noted to have a newly found right middle and lower lobe atelectasis with elevation of right hemidiaphragm on chest x-ray (CXR) and CT. Bronchoscopy done during that admission revealed mucus plugs in the right middle and lower lobes which were evacuated. At that time, he was discharged with prednisone and ICS/LABA inhaler which did not improve his symptoms. At current presentation, CTA of the chest revealed persistent but improved atelectasis compared to CT imaging from previous admission, but the right hemidiaphragm elevation persisted. Subsequent sniff test was positive for paradoxical motion of the right hemidiaphragm with normal movement of the left hemidiaphragm suggestive of right diaphragmatic paralysiCardiologic evaluation, including echocardiogram and stress test were unremarkable. The patient failed conservative management and pulmonary rehabilitation. He then underwent surgical plication of the right hemidiaphragm. Post-operative CXR showed improved right lung atelectasis and improved position of the right hemi diaphragm, with subsequent amelioration of his symptoms. DISCUSSION: The mechanism of neuromuscular involvement in COVID-19 infection is not fully understood. The viral spike protein unique to SARS-CoV-2 has high affinity to ACE2 receptors on skeletal muscle fibers1. Direct neuromuscular involvement by SARS-CoV-2 virus has been postulated to cause diaphragmatic paralysis1. Viral replication activates an inflammatory response leading to myotoxic injury via a cytokine storm2. CONCLUSIONS: Diaphragm dysfunction can be one of the consequences of COVID-19 infection. Neuromuscular injury impairs contraction of the diaphragm, which inhibits lung movement and contributes to impaired clearance of secretion leading to persistent dyspnea. REFERENCE #1: Paliwal VK, Garg RK, Gupta A, Tejan N. Neuromuscular presentations in patients with COVID-19. Neurol Sci. 2020;41(11):3039-3056. doi:10.1007/s10072-020-04708-8 REFERENCE #2: Ramani SL, Samet J, Franz CK, et al. Musculoskeletal involvement of COVID-19: review of imaging. Skeletal Radiol. Published online 2021. doi:10.1007/s00256-021-03734-7 DISCLOSURES: No relevant relationships by Ammar Ahmed, source=Web Response No relevant relationships by Madeeha Banu, source=Web Response No relevant relationships by Clifford Hecht, source=Web Response No relevant relationships by Kenneth Joseph, source=Web Response No relevant relationships by Swetha Paduri, source=Web Response No relevant relationships by Azib Shahid, source=Web Response

FUNCTIONAL POPLITEAL ARTERY ENTRAPMENT SYNDROME: INVESTIGATION WITH DYNAMIC AND DOPPLER ULTRASOUND

A. Background Functional popliteal artery entrapment syndrome (fPAES), a cause of exertional leg pain, has a clinical presentation and clinical findings that are often indistinguishable from those of other leg pain causes (1). This condition may also coexist and overlap in symptomatology with other leg pain causes, further complicating the diagnosis (2). Although fPAES is usually considered a rare cause of leg pain (3), the true incidence of this condition is unknown, and fPAES is likely underdiagnosed and underreported (4). A missed diagnosis may result in disease progression and the use of unnecessary invasive procedures (3), and untreated fPAES may lead to popliteal artery damage, embolization, and limb ischemia (5). Although a diagnostic method using a combination of dynamic ultrasound and MR imaging/MR angiography has been described for fPAES (5), to our knowledge, no investigational studies have been performed to assess the dynamic ultrasound findings in this entity. This study sought to evaluate the usefulness of dynamic plantar flexion and dorsiflexion of the calf and the effect on the popliteal artery Doppler waveform in patients with clinically suspected fPAES and no structural abnormality. B. Methods We performed a retrospective review of ultrasound studies in patients who presented with clinically suspected PAES over a 3-year period. The ultrasound studies consisted of an anatomic survey of the popliteal. Dynamic nonresistant dorsiflexion and plantar flexion evaluations of the popliteal artery plus spectral Doppler evaluations of the popliteal artery obtained in neutral, plantar flexion, and dorsiflexion positions were performed before and after patients exercised. Patients with anatomic abnormalities were excluded. The following parameters were assessed: The proportion of symptomatic knees versus asymptomatic knees in which plantar flexion and/or dorsiflexion of the foot resulted in popliteal artery compression. The peak systolic velocity (PSV) of the popliteal artery in all positions for knees with and knees without dynamic popliteal artery compression. The absolute value change in PSV of the popliteal artery from neutral to plantar flexion and from neutral to dorsiflexion in the pre- and postexercise state for knees with and knees without dynamic popliteal artery compression. ROC analysis for clustered data was used to assess the ability of PSV to distinguish between knees with and knees without arterial compression. C. Results A total of 88 knees (77 symptomatic, 11 asymptomatic) in 45 patients were included in the study. Dynamic arterial compression was observed in 38% (29/77) of symptomatic knees. No compression seen in asymptomatic knees. Both pre-exercise and postexercise knees with arterial compression had significantly higher absolute changes in PSV from neutral to plantar flexion versus knees without arterial compression (Table). There was a smaller significant change in PSV from neutral to dorsiflexion in the pre-exercise state. There was no significant change in PSV in the postexercise state from neutral to dorsiflexion or with respect to PSV values at any position between knees with and knees without arterial compression. D. Conclusions/Significance In patients with clinically suspected PAES without anatomic abnormality, dynamic ultrasound demonstrated compression of the popliteal artery in 38% of knees. No dynamic arterial compression was seen in asymptomatic knees. There was a significant elevation in PSV from neutral to plantar flexion in pre- and postexercise states and from pre-exercise neutral to dorsiflexion positions in knees with arterial compression versus knees without arterial compression. Tables [Table: see text] References Joy SM, Raudales R. Popliteal artery entrapment syndrome. Curr Sports Med Rep. 2015;14(5):364-367. Hislop M, Kennedy D, Cramp B, Dhupelia S. Functional popliteal artery entrapment syndrome: poorly understood and frequently missed? A review of clinical features, appropriate investigations, and treatment options. J Sports Med (Hindawi Publ Corp). 2014;2014:105953. Gaunder C, McKinney B, Rivera J. Popliteal artery entrapment or chronic exertional compartment syndrome? Case Rep Med. 2017;2017:6981047 Hislop M, Brideaux A, Dhupelia S. Functional popliteal artery entrapment syndrome: use of ultrasound guided Botox injection as a non-surgical treatment option. Skeletal Radiol. 2017;46(9):1241-1248. Williams C, Kennedy D, Bastian-Jordan M, Hislop M, Cramp B, Dhupelia S. A new diagnostic approach to popliteal artery entrapment syndrome. J Med Radiat Sci. 2015;62(3):226-229.

THE NATURAL HISTORY OF TYPE VII ALL INTRA-EPIPHYSEAL FRACTURES OF THE LATERAL MALLEOLUS

Background: Inversion-type ankle injuries are common in pediatric athletes, often resulting in lateral malleolar fractures (1). Ogden described the Type VII lateral malleolar physeal fracture as an injury in which the fracture line is totally within the secondary ossification center of the distal fibular epiphysis (2). The purpose of this paper is to report on the outcomes of 31 children participating in various types of sports activities who had sustained a Type VII fracture of the lateral malleolus. Methods: Here we report the results of an IRB approved prospective (longitudinal) cohort study carried out at a tertiary care pediatric hospital from March 2012 to December 2017. Eligible patients were those with a type VII (all epiphyseal) fracture of the lateral malleolus, either treated initially or seen in follow-up by the senior author. Exclusion criteria included those patients with all other lateral malleolar injuries and those with negative radiographs. Thirty-one children were enrolled during the study interval. Type VII fractures were classified as either transverse, oblique, or tip avulsion, depending on the trajectory and location of the fracture line within the secondary center of ossification of the lateral malleolus. We recorded the following demographic data: sex of the patient, age at the time of injury, mechanism of injury, sport involved, weight bearing status at the time of injury, treatment of the injury, and time from injury to release to sports activity. Children were permitted to return to sports when they had no discomfort on palpation and an ankle range of motion was equal to the uninvolved side. The primary outcome focus was radiographic status of the fracture at the time of the last clinical evaluation. Results: Thirty-one children with a Type VII fracture of the lateral malleolus were enrolled during the study interval. There were 8 girls and 23 boys. The average age at the time of injury was 107 months (˜9 years.) All the children had sustained a supination inversion-type injury while participating in a full spectrum of sports activities. Twenty-five children were initially unable to bear weight, and 6 could walk but with a limp. Twenty-six children were treated with a weight-bearing cast and crutches, and five of those who could bear weight were treated with a cast boot. Four fractures were oblique, 8 were transverse, and 19 were tip avulsions. All the children were asymptomatic and had a negative drawer test when cleared for sports participation at an average time of 3.5 months (range 2.5 to 4) after injury. Eighteen children had radiographs showing uneventful healing of the fractures (Figure 1) when released to full activity, but 13 (31%) healed with formation of a discrete os subfibulare (Figure 2.) The 18 fractures that healed uneventfully were located above the distal third of the fibular epiphysis. All of the 13 that healed with an os subfibulare were located either at the distal tip of the fibula (4) or at the anterior distal aspect of the tip (9) corresponding to the area of attachment of the ATFL. Conclusions: All of children sustaining a Type VII fracture of the lateral malleolus were able to return to full sports activities. Eighteen of the 31 Type VII fractures (58%) healed uneventfully. However, 13 (42%), healed with the formation of an os subfibulare. Since the presence of an os subfibulare has been associated with recurrent ankle instability and pain (3), it may be prudent to observe and even recommend ankle rehabilitation exercises for these children to help prevent long-term problems. [Figure: see text][Figure: see text] Su AW, Larson AN. Pediatric Ankle Fractures: Concepts and Treatment Principles. Foot Ankle Clin. 2015;20(4):705-719.26589088. Ogden JA. Injury to the growth mechanisms of the immature skeleton. Skeletal Radiol. 1981;6(4):237-253.7292021. Pill SG, Hatch M, Linton JM, Davidson RS. J Bone Joint Surg Am. 2013;95: e115(1-6) d http://dx.doi.org/10.2106/JBJS.L.00847 .

Multiple Myeloma Progression: Dependence on Bone Marrow Adipose Tissue

Multiple myeloma (MM) is characterized by clonal proliferation of transformed plasma cells1 and is extremely dependent on bone marrow (BM) niche molecules and cells, such as osteoclasts. Unlike osteoclasts, the roles of BM adipocytes (BMAs) in MM are poorly understood, despite their great therapeutic potential. This year we published a study of body composition PET/CT parameters that serve as predictors of monoclonal gammopathy of undetermined significance (MGUS) progression to MM(Veld J, O'Donnell EK, Reagan MR, et al. Abdominal adipose tissue in MGUS and multiple myeloma. Skeletal Radiol.). We found that recently diagnosed MM patients had higher abdominal white adipose tissue (WAT) than MGUS patients, even after correction for BMI. Bone Marrow Adipose Tissue (BMAT), a newly appreciated adipose depot with endocrine and paracrine signaling functions, resides near MM cells and has unique expression profiles and phenotypic responses compared to WAT. Because obesity and aging, risk factors for MM, correlate with increased BMAT, and BMAs and MM cells are closely physically associated, we hypothesized that BMAs contribute to an optimal microenvironment for MM cell proliferation and/or drug resistance.We performed direct and indirect co-culture experiments to study the effects of BMAT and BMAT-derived cytokines and lipids on MM proliferation and chemoresistance. MM cells were cultured on, or with conditioned media (CM) from, human and mouse BM-derived mesenchymal stem cells (MSCs) differentiated into adipocytes. MM proliferation, assessed by bioluminescence imaging, was dependent on MM cell line, MSC donor, and adipogenic stage.IL6 is a highly potent MM-supportive cytokine elevated in MM patient BM and thought to be derived mainly from MSCs. MM cells (OPM2 and MM1R) grown in CM from MSCs differentiated for 21 days into adipocytes (Fat CM) treated with IL6 neutralizing antibodies had significantly decreased proliferation vs MM cells treated with Fat CM alone. MM1S cells also showed this trend. These data identified BMAs as a novel BM IL6 source. MM cells typically proliferated in response to donor "lipid fractions", the oil layer on top of human hip surgery BM samples, after 24, 48 and 72 hours, although donor variability was again observed. Lipid droplet content (Oil Red O quantification) of these BMAs also significantly decreased upon culture with MM cells, suggesting that MM cells induce lipolysis or uptake BMAT lipids to fuel their proliferation.In contrast to the literature, we found that adiponectin can be either MM-supportive or MM-inhibitory, depending on the MM line tested and on the presence of dex. Certain MM cell lines (MM1S) became dexamethasone (dex) resistant when treated with Fat CM. Strikingly, all 3 cell lines tested (MM1S, MM1R and OPM2) showed significant decreases in cell number at 24, 48 and 72 hours after treatment with a neutralizing adiponectin antibody vs IgG control, when grown in the presence of 0.1μM dex + Fat CM (which contained high levels of adiponectin from ELISA analysis) (Fig 1A). These data suggest that adiponectin can induce dex resistance, indicating that adiponectin inhibitors + dex may be a novel MM therapy.Lastly, we developed a physiologically relevant 3D in vitro tissue engineered BMAT model utilizing biocompatible, porous silk fibroin scaffolds to more accurately define BMA-MM interactions. Our 3D models provide the correct mechanical robustness and biomaterial properties to mimic trabecular bone and unilocular BMAT (Fig 1 B-D). We generated long-term cultures of BMAT from MSCs and cultured MM cells (GFP+ MM1S) on these for up to 1 week, demonstrating the development of the first 3D BMAT artificial culture system, with or without MM cells. We are now using this novel platform to more deeply explore the relationship between BMAT and MM cells.In conclusion, BMAT likely plays a role in MM progression. 3D tissue engineered models of the BM milieu are a crucial link between 2D and in vivo models, maintaining the high-throughput capacity of 2D studies and the translational relevancy of in vivo models. Our data demonstrate important interactions between BMAT and MM cells, highlighting our need for further research into the roles of BM adipokines and adipocytes in MM pathogenesis and chemoresistance. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Type of Fracture Is an Independent Determinant of Long-Term Mortality in Older Patients With Hip Fracture: Systematic Review and Meta-Analysis of Longitudinal Studies

s 423 Results: In our study group, mean age was 61.1 11.7 years and mean BMI was 27.9 5.3 kg/m. At the time of baseline DXA scan, women with incident fracture (n5164) were shorter (1.527 0.065 m vs. 1.560 0.078 m; P!0.001), were older (65.0 11.5 years vs. 60.4 11.6 years; P!0.001), had a higher BMI (29.4 5.3 kg/m vs. 27.6 5.3 kg/m; P!0,001), had a lower femoral neck BMD (0.736 0.120 g/cm vs. 0.796 0.158 g/cm; P!0.001) and had a lower FN CSI (3.55 0.74 g/kg m vs. 3.88 0.81 g/kg m; P!0.001) than women without fracture (n5836). Body weight was not significantly different between women with incident fracture and women without simple logistic regression (odds ratio [95%CI]50.51 [0.385-0.653]). Femoral neck BMD was significantly (P!0.001) associated with the presence of fracture using a simple logistic regression (odds ratio [95%CI]50.041 [0.011-0.152]). Age, height and BMI were also significantly associated with the presence of fracture using simple logistic regressions (P! 0.001). When a multivariate logistic regression analysis was performed with the presence of fracture as a dependent variable and each age, FN BMD and FN CSI as independent variables, only FN BMD (P50.005) and FN CSI (P50.004) were found to be associated with the presence of fracture. Conclusion: This study suggests that FN CSI is an independent predictor of osteoporotic fractures in postmenopausal women. Further research is needed to determine the relative importance of FN CSI on fracture risk prediction in postmenopausal women.

FRI0231 A Comparative MRI Study of Cartilage Damage Patterns and Severity in Gout VS Rheumatoid Arthritis

BackgroundMRI of the wrist can be used to measure cartilage damage in rheumatoid arthritis (RA) (1) and this is usually diffuse in distribution, involving multiple joints. We have recently developed...

AB0974 Reproducibility of Magnetic Resonance Diffusion Weighted Imaging in Axial Spondyloarthritis Patients and Healthy Subjects

BackgroundDiffusion weighted imaging (DWI) is a magnetic resonance imaging (MRI) technique where the image contrast is dependent on the diffusion of the extracellular free water molecules. DWI is widely used...

AB1100 A case of frozen hip – a diagnosis we should consider more often?

BackgroundAdhesive Capsulitis of the hip or “frozen hip” is not a diagnosis well documented in rheumatological textbooks or literature. There are only a few isolated case reports of adhesive capsulitis...

AB0907 The prevalence of vertebral fractures and their relationship with bone mineral density in mild ankylosing spondylitis men pacients

BackgroundOsteoporosis (OP) is a frequent complication of ankylosing spondylitis (AS), even in early stages of the disease.ObjectivesDual x-ray absorptiometry for assessing bone mineral density (BMD) has limitations in patients with...

FRI0256 Arthralgias are predictive factors of foot involvement evaluated by ultrasonography in patients with systemic sclerosis: A prospective study

BackgroundFoot problems can be a major source of morbidity and disability in patients with SSc. Arthralgia is common in SSc and is poorly understood. It is usually attributed to mechanical...

SP0049 MRI in psoriatic arthritis - update on the current state

The clinical appearance of psoriatic arthritis (PsA) is very diverse, involving the spine, sacroiliac joints, peripheral joints and/or entheses, and accordingly MRI findings vary. PsA shares clinical manifestations with rheumatoid...

AB1273 Virtual anatomy of cervical nerve roots by 3-D MRI/CT fusion imaging

BackgroundBoth CT and MRI are widely known to be important tools in diagnosing spinal disorders. However, even when three-dimensional data are collected, images are often presented in two dimensions and...

AB1205 Whole-body magnetic resonance imaging in the assessment of the muscular involvement in juvenile dermatomyositis patients

BackgroundJuvenile dermatomyositis (JDM) is a rare autoimmune disease in childhood and the only available diagnostic criteria currently used are those defined by Bohan and Peter in 1975 1-3. Potential pitfalls...

AB1274 Lumbar facet joint effusion on 3-D MR myelography: A sign of rheumatoid back pain?

BackgroundThe articular hydropsy of knee is very popular clinical conditions. And, lumbar facet joint effusion is also very frequency disorders of spine, particularly those involved in RA, thoracic or lumbar...

Unusual Proximal Dislocation without Fracture: A Case Report

Carpal instability includes a broad spectrum of osseous and ligamentous injuries which have been subclassified into greater and lesser arc injuries, in addition to combinations of both (Mayfield et al. J Hand Surg [Am] 5:226-241, 1980; Yaeger et al. Skeletal Radiol 13(2):120-30, 1985). The injuries typically occur from a fall on the outstretched hand with the wrist in ulnar deviation, hyperextension, and intercarpal supination (Yaeger et al. Skeletal Radiol 13(2):120-30, 1985). The force classically propagates from the radial to the ulnar side of the wrist resulting in a fracture (greater arc) or dislocation (lesser arc) pattern with the extent of the injury occurring in an orderly pattern depending upon the degree of hyperextension and the duration and magnitude of the force (Mayfield et al. J Hand Surg [Am] 5:226-241, 1980; Yaeger et al. Skeletal Radiol 13(2):120-30, 1985). Multiple variations occur, including transradial styloid fractures as well as fractures through carpal bones surrounding the lunate (Mayfield et al. J Hand Surg [Am] 5:226-241, 1980; Yaeger et al. Skeletal Radiol 13(2):120-30, 1985; Kozin SH. J Am Acad Orthop Surg 6 (2): 114-20, 1998. Although carpal dislocations have been noted for many years, the mechanisms and classification have only been recently clarified. We report a case of a complex dislocation involving the entire proximal carpal row without an associated fracture. While this type of complex carpal dislocation has been previously described, to our knowledge, it has never been reported without a fracture of the forearm, wrist, or hand.

The natural evolution of neglected lesser tuberosity fractures in skeletally immature patients

Isolated avulsions of the lesser humeral tuberosity are rare injuries and only account for approximately 2% of all fractures of the proximal humerus. In skeletally immature patients, these fractures tend to be even more unusual. The fact that lesser tuberosity fractures in children are uncommon injuries is reflected in the paucity of literature on the management and outcome of these injuries. The first avulsion of the lesser tuberosity was described in 1895 in a 17-year-old boy with an ipsilateral humeral fracture. In 1985, White and Riley were the first to publish a formal report an isolated subscapularis avulsion in a child. So far, 33 cases of isolated avulsions of the lesser tuberosity in adolescent patients (patients aged < younger than 21 years) have been reported (Table I). One of the main reasons is that the diagnosis of this injury is not easy and often leads to a delayed diagnosis. We report 2 patients with neglected lesser tuberosity fractures during childhood and their late treatment. We also report a patient with an acute injury, treated surgically, with an excellent functional outcome.

Erratum to: Special Scientific Session of the International Skeletal Society, San Diego, California, September 2011

Erratum to: Skeletal Radiol (2011) 40:1121–1126 DOI Please note that the underlined author names below were unfortunately published with errors in two of the abstracts from the Special Scientific Session of the International Skeletal Society, California, September 2011. In addition, the award winner paper of the European Society of Skeletal Radiology 2011 is enclosed below as it was received following submission of the abstracts for publication.

Cranio‐meta‐diaphyseal dysplasia: 25 year follow‐up and review of literature

We report here on a 25-year follow-up of cranio-meta-diaphyseal dysplasia in a 31-year-old Caucasian male, who was reported in the literature at the age of 8 years [Langer et al. (1991); Skeletal Radiol 20:37-41]. He has hyperostotic craniofacial features with protruding lower jaw and midface hypoplasia. He has the typical radiographic features of wide long tubular bones without normal metaphyseal flaring and wide short tubular bones without normal diaphyseal constriction. We describe here his clinical and radiological findings and compare his case with those published in the literature. He is the oldest reported patient with this disorder giving some insight into the natural history of this rare skeletal dysplasia.

Pain as an emergent issue in thalassemia

Thalassemia is a congenital blood disorder often requiring chronic blood transfusions and iron chelation therapy [1,2]. While advances in treatment have resulted in increased life expectancy [3], extended life spans have exposed previously unidentified issues, including bodily pain. The aim of this study was to examine the prevalence, severity, predictors, and effects of pain in 265 adults/adolescents and 103 children with thalassemia. Overall, 69% of adults/adolescents reported bodily pain on the SF-36v2 health survey, with 28% reporting at least moderate pain. Parents reported pain in 56% of children using the PF-28 child health questionnaire, with only 11% reporting pain fairly often. There were no significant differences in pain in children with thalassemia compared with the general population. In adults/adolescents, pain increased significantly with age (P = 0.005), more so than in the general population. This study highlights the fact that children and young adults with thalassemia experience pain comparable to the general population, whereas older adults (aged 35+) experience greater pain. Our findings show that increased pain is associated with decreased quality of life and increased anxiety and depression.

Soft tissue mass at the infrascapular fossa.

Skeletal Radiol (2011) 40:105–106 DOI 10.1007/s00256-010-0915-3 TEST YOURSELF: QUESTION Soft tissue mass at the infrascapular fossa Seng-Choe Tham & Andrew E. Horvai & Thomas Link & Lynne Steinbach Published online: 15 April 2010 # The Author(s) 2010. This article is published with open access at Springerlink.com Question A 23-year-old man with a 5-year history of acute lymphoblastic leukemia (ALL) and who was in remission after chemotherapy treatment presenting with a shoulder mass (Figs. 1–4). Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which per- mits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. Fig. 1 Sagittal oblique T1-weighted fast spin echo image with chemical fat saturation and intravenous gadolinium reveals heteroge- neous enhancement of a mass within the infrascapular region (arrow) The diagnosis can be found at doi:10.1007/s00256-010-0916-2. This case was presented as Case 35 at the Members Meeting of the International Skeletal Society in Washington DC, 2009 S.-C. Tham : T. Link : L. Steinbach Department of Radiology, University of California, San Francisco, USA A. E. Horvai Department of Pathology, University of California, San Francisco, USA S.-C. Tham (*) Department of Radiology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore e-mail: Seng_Choe_Tham@ttsh.com.sg Fig. 2 The tumor was composed of short, intersecting fascicles of spindle cells with scattered small lymphocytes (original magnification, ×400)