Image-guided core needle biopsy for Ewing sarcoma of bone: a 10-year single-institution review.

OBJECTIVE: To evaluate the performance of image-guided core needle biopsy (IGCNB) for the diagnosis of Ewing sarcoma of bone. METHODS: All patients with a confirmed diagnosis of Ewing sarcoma who underwent IGCNB between January 2007 and December 2016 were included in this retrospective study. Analysis included mean age, skeletal distribution, imaging modality used for biopsy guidance, type of anaesthesia, needle type, number of passes, type of tissue sampled, and complications. RESULTS: The study included 139 patients (94 males and 45 females; mean age 18.7 years) who underwent 141 image-guided core needle biopsies as the primary diagnostic test. Of these, 101 were CT-guided, 38 ultrasound-guided, and 2 utilised both CT and ultrasound guidance. A total of 97.9% were diagnostic at first procedure. Of the 3 non-diagnostic cases, 2 underwent a further IGCNB and were positive, while 1 patient required an open surgical procedure. Only 1 patient (0.7%) suffered an immediate complication, and there were no recorded delayed complications. CONCLUSION: IGCNB is a safe procedure providing a positive diagnosis of Ewing sarcoma of bone in a very high percentage of cases. It should be the first-line method for establishing a diagnosis in suspected Ewing sarcoma of bone. KEY POINTS: • Image-guided core needle biopsy is a safe procedure providing a positive diagnosis of Ewing sarcoma of bone in a very high percentage of cases. • Image-guided core needle biopsy should be the first-line method for establishing a definitive diagnosis in Ewing sarcoma and should be performed at a specialist sarcoma referral centre. • When technically feasible, extra-osseous soft tissue alone can be sampled with confidence as there is no difference in diagnostic performance whether bone or an extra-osseous soft tissue component of the tumour is sampled.

The incidence of skip metastases on whole bone MRI in high-grade bone sarcomas.

INTRODUCTION: Skip metastases have been described with osteosarcoma, Ewing sarcoma and rarely chondrosarcoma. The aim of this study was to determine the incidence of skip metastases on whole bone MRI in all primary high-grade sarcomas of the major long bones. MATERIALS AND METHOD: Retrospective review of patients from April 2007 to April 2019 with high-grade primary bone sarcomas of the humerus, radius, ulna, femur, tibia or fibula who had whole bone MRI at initial staging. Data collected included age, sex, tumour type, presence and location of skip metastases based on whole bone MRI and presence of distant metastases (the skeleton and lung). RESULTS: The study included 216 males and 171 females with mean age 30.6 years (range 4-92 years). Tumour types were as follows: High-grade osteosarcoma n = 202, Ewing sarcoma n = 68, high-grade chondrosarcoma n = 44, dedifferentiated chondrosarcoma n = 37, high-grade spindle cell sarcoma n = 29 and angiosarcoma n = 7. Skip lesions were identified in 63 (16.3%). However, after taking into account the presence of distant skeletal (n = 11) and pulmonary (n = 33) metastases, the overall incidence of skip metastases was 6.5%, occurring in 15 (7.5%) high-grade osteosarcomas, 3 (4.5%) Ewing sarcoma, 1 (2.8%) high-grade chondrosarcoma, 4 (10.8%) dedifferentiated chondrosarcomas, and 2 (6.9%) high-grade spindle cell sarcomas. A false positive MRI diagnosis of skip metastasis was made in 4 cases, 3 enchondromata and one focal nodular marrow hyperplasia. CONCLUSION: The current study has documented the incidence of skip metastases in common types of high-grade primary bone sarcoma. The possibility of false positive skip metastases has also been highlighted.

Whole-body MRI vs bone scintigraphy in the staging of Ewing sarcoma of bone: a 12-year single-institution review.

OBJECTIVE: To compare whole-body MRI (WB-MRI) at 1.5/3T and bone scintigraphy in the skeletal staging of Ewing sarcoma (ES) of bone. METHODS: All patients with a histological diagnosis of ES of bone between 2007 and 2018 were retrospectively reviewed. The analysis included gender, mean age, skeletal distribution, and prevalence of skeletal metastases on WB-MRI and bone scintigraphy. RESULTS: The study group comprised 182 patients with a mean age of 18.0 years (range 2-56 years), 126 males and 56 females. Skeletal metastases were detected overall in 30 patients (16.5%), in 23 of 96 patients (24%) who underwent WB-MRI, and in 20 of 118 patients (16.9%) who underwent bone scintigraphy. Of 71 patients who underwent both WB-MRI and bone scintigraphy, skeletal metastases were detected on both modalities in 13 (18.3%), while in 4 patients, skeletal metastases were identified on WB-MRI alone. There were no patients in whom skeletal metastases were identified on bone scintigraphy alone. Of 13 patients with skeletal metastases who underwent both studies, WB-MRI showed a greater number of metastatic foci in 10 (76.9%). However, scintigraphy was superior to WB-MRI in detecting skull vault lesions, but did show false-positive results around the long bone growth plates. CONCLUSION: WB-MRI is more sensitive than bone scintigraphy in detecting skeletal metastases in ES of bone, with the exception of skull vault metastases. Consideration should be given to replacing bone scintigraphy with WB-MRI. KEY POINTS: • Whole-body MRI is more sensitive than bone scintigraphy in detecting skeletal metastases in Ewing sarcoma of bone. • Whole-body MRI can safely replace bone scintigraphy for staging of the skeleton, with the acknowledgement of the possibility of missing a clinically occult skull vault metastasis.

Bilateral traumatic abducens nerve avulsion: A case series and literature review.

Although abducens nerve palsy is an established sequela of head trauma - given the prolonged intracranial course of the nerve - bilateral injury is rare. Here, we present two cases of bilateral traumatic abducens nerve avulsion, in the absence of regional fractures, one of which presented two months following the initial trauma. Additionally, we review the current literature on bilateral abducens nerve palsy secondary to trauma, discussing the anatomy of the nerve's course and potential mechanisms of injury.

Demyelination preceding a diagnosis of central nervous system lymphoma.

We present a case of primary central nervous system lymphoma (PCNSL) co-existing with demyelination in a young immunocompetent woman. The patient presented with an expansile, enhancing lesion in the right occipital lobe which was initially attributed to tumefactive demyelination and subsequently proven to be PCNSL. PCNSL is an uncommon malignancy, particularly in young immunocompetent patients, and on MRI classically manifests as a homogeneously enhancing solitary mass with a predilection for periventricular and superficial locations, often contacting ventricular and meningeal surfaces. Tumefactive demyelinating lesions typically present as large white matter lesions with little mass effect or vasogenic oedema and "open-ring" enhancement, with the incomplete portion of the ring on the grey matter side of the lesion. PCNSL and tumefactive demyelinating lesions share some radiological features and thus, as our case report highlights, differentiating between them can be challenging. We discuss how the application of conventional and advanced MRI techniques combined with clinical and laboratory findings can lead to a precise diagnosis, potentially obviating the need for biopsy and facilitating prompt and appropriate treatment.

Fragile X-associated tremor/ataxia syndrome: An under-recognised cause of tremor and ataxia.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a progressive degenerative movement disorder resulting from a fragile X "premutation", defined as 55-200 CGG repeats in the 5'-untranslated region of the FMR1 gene. The FMR1 premutation occurs in 1/800 males and 1/250 females, with FXTAS affecting 40-45% of male and 8-16% of female premutation carriers over the age of 50. FXTAS typically presents with kinetic tremor and cerebellar ataxia. FXTAS has a classical imaging profile which, in concert with clinical manifestations and genetic testing, participates vitally in its diagnosis. The revised FXTAS diagnostic criteria include two major radiological features. The "MCP sign", referring to T2 hyperintensity in the middle cerebellar peduncle, has long been considered the radiological hallmark of FXTAS. Recently included as a major radiological criterion in the diagnosis of FXTAS is T2 hyperintensity in the splenium of the corpus callosum. Other imaging features of FXTAS include T2 hyperintensities in the pons, insula and periventricular white matter as well as generalised brain and cerebellar atrophy. FXTAS is an under-recognised and misdiagnosed entity. In patients with unexplained tremor, ataxia and cognitive decline, the presence of middle cerebellar peduncle and/or corpus callosum splenium hyperintensity should raise suspicion of FXTAS. Diagnosis of FXTAS has important implications not only for the patient but also, through genetic counselling and testing, for future generations.