Hibernoma--correlation of histopathology and magnetic-resonance-imaging features in 10 cases

OBJECTIVE, DESIGN AND PATIENTS: Hibernoma is an uncommon, slow-growing, benign soft-tissue tumour resembling brown adipose tissue. The histological appearances are well-documented, but there are relatively few descriptions of the magnetic resonance (MR) imaging features. We report a retrospective comparison of the histological and MR appearances of ten hibernomas of the extremities, classified histologically into lipoma-like [<70% multivacuolated adipocytes (MVAs)] and non-lipoma-like hibernomas (>70% MVAs).

RESULTS

The lipoma-like hibernomas measured 4-27 cm in maximum size. All were well-defined on MR imaging and histology except for one subcutaneous lesion that blended in with surrounding fat histologically. All lesions were isointense with subcutaneous fat on T1- and T2-weighting apart from one lesion that was predominantly slightly hypointense on T1-weighting and predominantly slightly hyperintense on T2-weighting and STIR. Two slightly inhomogeneous lesions contained thin (<5 mm thickness) tortuous vessels. One patient received intravenous contrast, but the lesion did not enhance. The six non-lipoma-like hibernomas measured 2.5-15.5 cm in maximum size and all were unencapsulated. Three were well-defined and three partly ill-defined on MR imaging. There were no significant differences in the MR characteristics of the non-lipoma-like variants. On T1-weighting, the non-lipoma-like hibernomas that contained >90% MVAs were predominantly slightly hypointense to subcutaneous fat. One lesion was isointense with subcutaneous fat, but this lesion only contained from 80-90% MVAs. All non-lipoma-like lesions were slightly hyperintense on STIR but so too were two of the four lipoma-like lesions. Four of the six non-lipoma-like lesions showed marked or moderate inhomogeneity due to thick septa and prominent vessels. Of the two cases that received intravenous contrast, both showed enhancement corresponding to regions of >90% MVAs or prominent vessels within fibrous septa.

CONCLUSIONS

MR imaging has shown some distinguishing features between lipoma-like and non-lipoma-like hibernomas. Lipoma-like hibernomas are usually isointense with subcutaneous fat on T1-weighting, are either homogeneous or slightly inhomogeneous and may contain thin tortuous vascular structures. Non-lipoma-like hibernomas are pre-dominantly slightly hypointense to subcutaneous fat on T1-weighting, often display marked or moderate inhomogeneity with prominent septa and vessels and enhancement is typical. The appearances of non-lipoma-like hibernomas are not diagnostic and may be mimicked by lipoma variants and by well-differentiated liposarcoma or atypical lipoma.

Imaging of joint tumors

The paper gives an overview of the present nosological classification and imaging features of synovial tumors and tumor-like conditions of joints. The merits of each imaging technique will be emphasized.

Ewing's sarcoma of bone: the detection of specific transcripts in a large, consecutive series of formalin-fixed, decalcified, paraffin-embedded tissue samples using the reverse transcriptase-polymerase chain reaction

AIMS

(i) To report on the routine use of the reverse transcriptase-polymerase chain reaction (RT-PCR) technique on decalcified or non-decalcified, formalin-fixed, paraffin-embedded tissue (FFPET) for translocation detection, with particular emphasis on improved RNA extraction methodology and the use of PCR primers designed to generate small amplicons. (ii) To report on the relative incidences of translocation types and transcript variants in a large, single institution series of Ewing's sarcoma of bone.

METHODS AND RESULTS

Using RT-PCR to detect specific transcript variants, we analysed FFPET from 54 consecutive cases of Ewing's sarcoma of bone. We used 'gold standard' detection methods on corresponding fresh and fresh frozen tissue to validate the technique. We have demonstrated the effective use of RT-PCR on decalcified and non-decalcified FFPET samples for sarcoma-specific translocation detection (96% sensitivity, 100% specificity). Tissue decalcification did not affect the detection rate. The relative incidence of Ewing's sarcoma-specific translocation types and transcript variants was entirely consistent with previously published data.

CONCLUSIONS

With equal effectiveness, RT-PCR can be applied to both acid decalcified and non-decalcified FFPET for (Ewing's sarcoma) translocation detection and the technique can be introduced into routine practice in histopathology departments.

Benign primary tumours of the ribs

Benign primary tumours of the ribs are rare and may be identified during the investigation of a clinically suspected abnormality or as an incidental finding. This review describes the spectrum of benign tumours that can involve the rib and illustrates the radiographic, computed tomography (CT) and magnetic resonance (MR) imaging appearances that may facilitate diagnosis.

Imaging of infectious spinal disorders in children and adults

The aim of this review article is to outline the imaging of infectious disorders of the spine in adults and children. The clinical presentation, potential routes of infection and the pathogens commonly identified are discussed. The value of different imaging modalities in the diagnosis of spinal infection is presented including radiographic, CT, MR imaging and Nuclear Medicine including PET. The use of image guided techniques for diagnosis and subsequent treatment is briefly covered. The major differential diagnoses of infectious disorders of the spine are identified and contrasted with the typical findings in infection. The use of follow up imaging is evaluated.

The effect of X-rays on bone: a pictorial review

The deleterious effects of X-rays on bone have been recognised for almost a century and continue to be seen today because of improved survival in patients treated for malignancy with radiotherapy with or without other treatments. In this pictorial review we present the imaging features of radiation damage to bone highlighting the differences seen in the immature skeleton and post-skeletal fusion. In the former, damage is greatest to the physis resulting in growth disturbances. In the mature skeleton there is a spectrum of changes from mild osteopenia, through disordered attempts at healing with varying degrees of sclerosis, radionecrosis which may lead to acute fractures following minimal trauma and insufficiency fractures both with refractory healing to the dreaded complication of sarcomatous transformation. The imaging appearances are illustrated and the features that help distinguish malignant change from other complications stressed.

Chondroblastoma of bone: long-term results and functional outcome after intralesional curettage

We undertook this retrospective study to determine the rate of recurrence and functional outcome after intralesional curettage for chondroblastoma of bone. The factors associated with aggressive behaviour of the tumour were also analysed. We reviewed 53 patients with histologically-proven chondroblastoma who were treated by intralesional curettage in our unit between 1974 and 2000. They were followed up for at least two years to a maximum of 27 years. Seven (13.2%) had a histologically-proven local recurrence. Three underwent a second intralesional curettage and had no further recurrence. Two had endoprosthetic replacement of the proximal humerus and two underwent below-knee amputation after aggressive local recurrence. One patient had the rare malignant metastatic chondroblastoma and eventually died. The mean Musculoskeletal Tumour Society functional score of the survivors was 94.2%. We conclude that meticulous intralesional curettage alone can achieve low rates of local recurrence and excellent long-term function.

Giant-cell tumours of bone of the hand and wrist: a review of imaging findings and differential diagnoses

Giant-cell tumour of bone (GCTOB) is a benign, locally aggressive, primary bone tumour. Involvement of the distal radius accounts for between 10 and 12% of cases of GCTOB, with the bones of the hand and wrist being rarely affected. GCTOB most commonly affects skeletally mature patients between the ages of 20 and 40 years, with the peak incidence being in the third decade. Women are affected slightly more commonly than men. GCTOB involving the bones of the hand most commonly occurs in a central location, which differs from the usual eccentric location seen in GCTOB at other sites. The radiographic features of GCTOB in the hand and wrist are presented. The role of bone scintigraphy, computed tomography and magnetic resonance imaging is discussed. Evaluation of the postoperative patient is also addressed, including the role of dynamic contrast-enhanced magnetic resonance imaging. A comprehensive review of the potential differential diagnoses that should be considered when GCTOB is suspected in the hand and wrist is also presented.

Intramedullary and extramedullary fat globules on magnetic resonance imaging as a diagnostic sign for osteomyelitis

We retrospectively studied the frequency of persistent foci of fat signal on magnetic resonance (MR) imaging in osteomyelitis to assess its frequency, cause and diagnostic value. The radiographs and MR scans of 100 patients with a final diagnosis of osteomyelitis referred to a specialist orthopaedic oncology service with the presumptive diagnosis of a bone tumour were reviewed. The MR signal and morphological characteristics were recorded with particular attention to the presence of persistent fat signal within the infected area, which was classified as diffuse or focal. Seventeen cases were classified on radiographic grounds as acute, 63 as subacute and 20 as chronic osteomyelitis. In the acute group 12 (70%) showed replacement of the marrow with fluid containing residual fatty signal, diffuse in seven and focal in five cases. Two cases showed predominantly fatty marrow with very early marrow oedema and three cases (18%) showed replacement of marrow fat with fluid and no residual fatty foci. None of the subacute group showed foci of fatty signal and two cases of inactive sclerosing osyeomyelitis in the chronic group showed restoration of normal marrow. Persistent fatty signal within the bone as well as soft tissues on MR imaging is a frequent finding in acute osteomyelitis. Radiological-pathological correlation suggests that the increasing intramedullary pressure leads to septic necrosis with death of the lipocytes and release of free fatty globules. This characteristic, but not pathognomonic, MR finding supports the diagnosis of osteomyelitis and may help to exclude the presence of a tumour.

Surface lesions of the bones of the hand

Surface lesions involving the bones of the hand are uncommon. This pictorial review illustrates the spectrum of conditions including benign primary bone tumours, malignant primary bone tumours and non-neoplastic disorders. The review focuses on the radiographic appearances of these lesions and other techniques such as CT and MR imaging that may suggest a specific diagnosis.

Managing acute cardiac patients in and out of the hospital setting

The National Service Framework (NSF) for Coronary Heart Disease (CHD) (Department of Health, 2003) sets the standard of treating eligible acute myocardial infarction (AMI) patients within 60minutes of a call for help in order to improve survival rates and long-term quality-of-life for heart-attack patients.

Calcific myonecrosis: a report of ten new cases with an emphasis on MR imaging

The aim of this study is to report the typical radiographic and MR imaging features of calcific myonecrosis, which help to distinguish this rare entity from other causes of a calcifying calf mass. Ten patients with a final diagnosis of calcific myonecrosis were referred to a specialist orthopaedic oncology service in a 5-year period with the presumptive diagnosis of malignancy based on recent clinical presentation and imaging findings. Radiographs were available for retrospective review in all ten cases and MR imaging in six. All patients presented with a slow-growing painless calf mass. All gave a history of major trauma to the lower leg many years before, but in only two cases did the referring clinician query whether trauma might be a contributory factor. Radiographs showed well-defined fusiform mineralised masses up to 25 cm in length arising within the calf. The calcification was consistently peripheral and plaque-like. Ossification was not present. MR imaging showed the anterior compartment to be involved in four cases and all compartments in two. T1- and T2-weighted images showed peripheral low signal intensity, more prominent on the T2-weighted images, because of the peripheral mineralization. The contents of the masses were variable on T1-weighted images depending on the differing amounts of blood breakdown products and were heterogeneous on T2-weighted images. The latter may be explained by a combination of the mineralisation and T2 shortening due to blood breakdown products. A gadolinium chelate, administered in two cases, failed to show any appreciable enhancement. Calcific myonecrosis has characteristic clinical, radiographic and MR features that should make the condition easy to recognise. Despite its rarity, it should be included in the differential diagnosis of focal mineralisation of the calf.

Differential diagnosis of tumours and tumour-like lesions of the infrapatellar (Hoffa?s) fat pad: pictorial review with an emphasis on MR imaging

A variety of intrinsic and extrinsic tumours and tumour-like conditions may affect the infrapatellar (Hoffa's) fat pad (IFP). MR imaging is the technique of choice in evaluating these conditions, but correlation with radiographs is important to identify those lesions producing mineralization. This pictorial review illustrates the spectrum of mass-like lesions that can affect the IFP, emphasizing the radiographic and MR findings that suggest a specific diagnosis.

The penumbra sign in subacute osteomyelitis

The penumbra sign is a characteristic magnetic resonance (MR) feature of subacute osteomyelitis. It can be identified on unenhanced T1-weighted spin echo images as a discrete peripheral zone of marginally higher signal intensity than the central bony abscess cavity and the surrounding lower signal intensity of the reactive new bone and oedema.

Imaging features of intraosseous ganglia: a report of 45 cases

The aim of this study is to report the spectrum of imaging findings of intraosseous ganglia (IG) with particular emphasis on the radiographic and magnetic resonance (MR) features. Forty-five patients with a final diagnosis of IG were referred to a specialist orthopaedic oncology service with the presumptive diagnosis of either a primary or secondary bone tumour. The diagnosis was established by histology in 25 cases. In the remainder, the imaging features were considered characteristic and the lesion was stable on follow-up radiographic examination. Radiographs were available for retrospective review in all cases and MR imaging in 29. There was a minor male preponderance with a wide adult age range. Three quarters were found in relation to the weight-bearing long bones of the lower limb, particularly round the knee. On radiographs all were juxta-articular and osteolytic; 74% were eccentric in location, 80% had a sclerotic endosteal margin and 60% of cases showed a degree of trabeculation. Periosteal new bone formation and matrix mineralization were not present. Of the 29 cases that underwent MR imaging, 66% were multiloculated. On T1-weighted images the IG contents were isointense or mildly hypointense in 90% cases. Forty-one per cent of the cases showed a slightly hyperintense rim lining that enhanced with a gadolinium chelate. Thirty-eight per cent were associated with soft tissue extension and 17% with a defect of the adjacent articular cortex. Fifty-five per cent showed surrounding marrow oedema on T2-weighted or STIR images and two cases (7%) a fluid-fluid level prior to any surgical intervention. The authors contend that it is semantics to differentiate between an IG and a degenerate subchondral cyst as, while the initial pathogenesis may vary, the histological endpoint is identical, as are the imaging features apart from the degree of associated degenerative joint disease. IGs, particularly when large, may be mistaken for a bone tumour. Correlation of the typical radiographic and MR imaging features will indicate the correct diagnosis and obviate the need for biopsy.

Calcific haemorrhagic bursitis anterior to the knee mimicking a soft tissue sarcoma: report of two cases

We describe the radiological and pathological findings of two cases of calcific haemorrhagic bursitis, one involving the superficial infrapatellar bursa and the other the prepatellar bursa. It was the presence of dystrophic calcification within the lesion that suggested a mineralizing soft tissue sarcoma such as synovial sarcoma. As the radiographic and MR features of the two conditions can be similar but the appropriate management very different, rare calcifying haemorrhagic bursitis needs to be included in the differential diagnosis of masses adjacent to the knee joint showing calcification.

The MR imaging appearances and natural history of seromas following excision of soft tissue tumours

Fluid collections (seromas) may accumulate at the site of surgery following excision of musculoskeletal soft tissue tumours. The aim of this retrospective study was to review the magnetic resonance (MR) imaging features of postoperative seromas identifying changes over time on follow-up scans. A total of 170 MR scans from 80 patients were reviewed showing one or more seromas. All patients had undergone previous surgery for a musculoskeletal soft tissue tumour. The typical MR appearances of a seroma were shown to be a well-defined oval or rounded (54%) soft tissue mass, arising at the site of previous surgery, with a thin, dark pseudocapsule, surrounding soft tissue oedema (80%), homogeneous contents that are hypointense (relative to adjacent muscle) on T1-weighted images (74%) and hyperintense on T2-weighted and STIR images (79%). Approximately one-quarter of cases revealed atypical features including hyperintense contents on T1-weighted (26%) and/or heterogeneous contents on T2-weighted images (21%), reflecting the breakdown of blood products and organization of the fluid collection. A distinctive fine feathery pattern arising from the inner surface of the seroma or from septations was identified in 10% of cases. In those patients who underwent one or more follow-up scans, the volume of the seromas decreased in 66% cases, remained unchanged in 15% and increased in 19%. Seromas are not an uncommon finding (<10% of cases) following surgery for a soft tissue tumour. The majority of cases show the typical MR features of a fluid collection. The pitfalls in differentiating an atypical seroma from a recurrent soft tissue sarcoma are discussed.

Bone within a bone

The "bone within a bone" appearance is a well-recognized radiological term with a variety of causes. It is important to recognize this appearance and also to be aware of the differential diagnosis. A number of common conditions infrequently cause this appearance. Other causes are rare and some remain primarily of historical interest, as they are no longer encountered in clinical practice. In this review we illustrate some of the conditions that can give the bone within a bone appearance and discuss the physiological and pathological aetiology of each where known.

MR imaging in the assessment of residual tumour following inadequate primary excision of soft tissue sarcomas

The purpose of this retrospective study was twofold: firstly, to assess the ability of MR imaging in confirming/excluding the presence of residual tumour following inadequate primary excision of soft tissue sarcomas; and secondly, to assess the accuracy of the original radiologists report as compared with a retrospective review of the scan hard copy in confirming/excluding. A total of 111 cases were identified that fulfilled the inclusion criteria of inadequate primary surgery followed by a MR scan and subsequent wide re-excision of the surgical field. The gold standard for the assessment of the MR imaging studies was histological examination of the re-excision specimens. Histological examination revealed residual tumour in 63 (56.7%) cases. In 48 cases the residual tumour was classified macroscopic (maximum diameter >10 mm) and 15 cases microscopic (maximum diameter </=10 mm). The original radiologists reports failed to indicate the presence or absence of tumour in 7 (6.3%) cases. In the remaining 104 cases the diagnostic performance of MR imaging gave a sensitivity of 0.64, specificity of 0.93, positive predictive value of 0.93 and negative predictive value of 0.67. In 12 of the 21 false-negative scans the residual tumour was microscopic. Subjective assessment of the radiologist's reports indicated that the proportion of equivocal reports was much higher in both the false-negative and false-positive groups as compared with the true groups. An unblinded retrospective review of the scan hard copies only differed from the original radiologists report in 8 (7.2%) cases. Contrast-enhanced sequences were not routinely obtained in this series. The results suggest that the poor negative predictive value can be attributed more to limitations of the MR scan and not to failures in observation or interpretation by the radiologists. Despite the low negative predictive value, MR imaging remains useful in planning the re-excision surgery by identifying the site and extent of the original operation and size of major residual tumour.

Pencil-core granuloma of the distal radio-ulnar joint: an unusual presentation as soft-tissue sarcoma after 45 years

A case of pencil-gore granuloma occurring 45 years after he initial injury is described. The clinical and radiological presentation was suggestive of a soft-tissue sarcoma. The diagnosis was confirmed by biopsy, which also revealed foreign body fragments which, on spectometric analysis, had high concentrations of carbon and aluminium.

Neoplastic transformation and tumour-like lesions in Paget's disease of bone: a pictorial review

The development of a sarcoma is the most serious complication of Paget's disease of bone. Although its incidence is <1% of those with the underlying disease, it is important to recognise the imaging features of these tumours as Paget's disease of bone is relatively common in the ageing population in certain parts of the world. The purpose of this pictorial review is to present the imaging features of Paget's sarcoma based on one orthopaedic oncology centres experience in 49 patients; however, not all masses or destructive lesions arising in association with Paget's disease are sarcomas and not all the tumours are malignant. This review also includes other malignancies which may arise in pagetic bone as well as tumour-like manifestations of Paget's disease.

Intraosseous lipoma: report of 35 new cases and a review of the literature

OBJECTIVE

To identify the common imaging features of intraosseous lipomas on radiographs, magnetic resonance imaging (MRI) and computed tomography (CT), and review their histological features.

DESIGN AND PATIENTS

Thirty-five previously unreported cases of intraosseous lipoma were reviewed and a meta-analysis was performed of another 110 cases identified from the English language literature.

RESULTS

The mean age at presentation is 43 years. Sex distribution is nearly equal. Lipomas occur most frequently in the lower limb (71% overall), particularly in the os calcis (32%). Other common sites include the metaphyses of long bones, where lesions are typically eccentric. Lipomas are usually well defined, but marginal sclerosis is commoner in lesions of the os calcis (61%) than at other sites (38%). Calcification is also more frequent in the os calcis (62%), and almost invariably centrally located. Calcification at other sites is less common (30%), and is more variable in appearance. Bone expansion is less common (30%), and usually minimal. Fat necrosis and cyst formation identified on MRI is common (67%), and more frequent in the os calcis.

CONCLUSIONS

Although there is correlation between the histological and radiological features of intraosseous lipomas in general, some discrepancies occur in the radiological appearances of lipomas in different sites. The evidence that these lesions are true benign tumours of fat is controversial. Several aetiological factors have been implicated in their development. The constant location of os calcis lesions at the critical angle suggests an aetiology that may be related to biomechanical lines of stress. In other instances it is possible that involution of pre-existing lesions may lead to the development of lipomas.

A Ca2+-induced mitochondrial permeability transition causes complete release of rat liver endonuclease G activity from its exclusive location within the mitochondrial intermembrane space. Identification of a novel endo-exonuclease activity residing within the mitochondrial matrix

Endonuclease G, a protein historically thought to be involved in mitochondrial DNA (mtDNA) replication, repair, recombination and degradation, has recently been reported to be involved in nuclear DNA degradation during the apoptotic process. As a result, its involvement in mtDNA homeostasis has been called into question and has necessitated detailed analyses of its precise location within the mitochondrion. Data is presented localizing rat liver endonuclease G activity exclusively to the mitochondrial intermembrane space with no activity associated with either the interior face of the inner mitochondrial membrane or with the mitochondrial matrix. Additionally, it is shown that endonuclease G can be selectively released from the mitochondrion via induction of a Ca2+-induced mitochondrial permeability transition and that, upon its release, a further nuclease activity loosely associated with the interior face of the inner mitochondrial membrane and distinct in its properties from that of endonuclease G can be detected.

MR imaging features of giant pre-sacral schwannomas: a report of four cases

Benign giant sacral schwannoma is an uncommon cause of destruction of the sacrum. This report details four cases of a variant of this condition called giant presacral schwannoma (GPSS). On MR imaging the features are of a large, well-defined presacral soft tissue mass, arising just to one side of the midline with minor involvement of the bone. The typical MR features of a benign peripheral nerve sheath tumour are not seen. The tumours appear heterogeneous due to long-standing degeneration. Biopsy is advocated as the appearances of GPSS can be similar to a malignant peripheral nerve sheath tumour (malignant schwannoma).

Primary synovial chondromatosis and synovial chondrosarcoma: a pictorial review

This article illustrates the imaging characteristics of primary synovial chondromatosis (PSC) using 20 cases referred to a tertiary orthopaedic oncology centre. Three quarters of patients presented with a large intra-articular soft tissue mass and a suspected clinical and radiological diagnosis of malignancy made in the referring centres. Radiographs demonstrated fine cartilaginous mineralisation in the soft tissue masses in 85% cases and bone erosions were shown on MR imaging in 80%. Malignant transformation to chondrosarcoma was proven in 2 cases with longstanding disease. There were no specific MR features to distinguish these cases with malignant change from PSC alone. Primary synovial chondromatosis should be considered in the diagnosis of the monarticular presentation of an intra-articular soft tissue mass, particularly in the presence of superficial bone erosions and signal voids due to the mineralisation.

Metachronous haemorrhagic epithelioid and spindle cell haemangioma of bone

We present the case of a 7-year-old boy with a haemorrhagic and spindle cell haemangiomas of the ring finger. The lesions appeared in a metachronous fashion initially in the distal phalanx and 16 months later in the proximal phalanx. Radiography revealed expansile lytic lesions of the phalanges. Haemorrhagic epithelioid and spindle cell haemangioma is a benign condition which, due to its unusual morphology, can be confused with more aggressive or malignant endothelial neoplasms. This condition with its possible multifocal presentation should be considered when diagnosing vascular lesions of bone in order that appropriate treatment can be implemented.

Subperiosteal schwannomas of the femur

We report a case of two adjacent femoral subperiosteal schwannomas in a 38-year-old man. To our knowledge, this is the first report of a schwannoma arising as a surface lesion of bone. Radiographs showed focal cortical scalloping and MR imaging two small hyperintense nodules on T2-weighted and STIR images which enhanced with a gadolinium chelate.

Potassium channel KV alpha1 subunit expression and function in human detrusor muscle

PURPOSE

We determined whether voltage gated K+ (KV) channels are expressed and functional in human detrusor smooth muscle

MATERIALS AND METHODS

Information on KV channels was obtained using electrophysiological patch clamp, immunofluorescence, Western blot and isometric tension recording techniques

RESULTS

Patch clamp recordings from detrusor cells revealed a Ca2+ independent K+ current that was activated by depolarization in a voltage range near the resting potential of detrusor smooth muscle. The current was inhibited by 3,4-diaminopyridine, a blocker of KV channels. Antibodies targeted to KValpha1 subunits revealed KV1.3 and KV1.6 expression in whole bladder tissue samples and specifically in detrusor smooth muscle cells. New specific blockers of KValpha1 channel currents (correolide and recombinant agitoxin-2) had a myogenic effect, characterized by increased amplitude of spontaneous contractions without an effect on the frequency of contractions or on resting baseline tension.

CONCLUSIONS

KValpha1 subunits are expressed and functionally important in human detrusor muscle.

MR imaging of brown tumour with fluid-fluid levels: a report of three cases

Fluid-fluid levels on CT and MR imaging are a typical feature of aneurysmal bone cysts but have also been reported in many other osseous lesions containing haemorrhage. We report fluid-fluid levels in four brown tumour in three patients with primary hyperparathyroidism in which the initial radiological diagnosis was thought to be a bone tumour. To the authors' knowledge, this is the first time that association has been reported in the international literature.

Imaging the complications of osteochondromas

Most osteochondromas are asymptomatic and incidental with typical radiographic characteristics. When symptomatic, complications due to space-occupying effects, mechanical deformity, or malignant transformation are usually the underlying causes. This article addresses the imaging strategy for their identification and evaluation.

Risk factors for survival and local control in chondrosarcoma of bone

We studied 153 patients with non-metastatic chondrosarcoma of bone to determine the risk factors for survival and local tumour control. The minimum follow-up was for five years; 52 patients had axial and 101 appendicular tumours. Surgical treatment was by amputation in 27 and limb-preserving surgery in 126. The cumulative rate of survival of all patients, at 10 and 15 years, was 70% and 63%, respectively; 40 patients developed a local recurrence between 3 and 87 months after surgery and 49 developed metastases. Local recurrence was associated with poor survival in patients with concomitant metastases but not in those without. On multivariate analysis independent risk factors for rates of survival include extracompartmental spread, development of local recurrence and high histological grade. Independent risk factors for local recurrence include inadequate surgical margins and tumour size greater than 10 cm. Location within the body, the type of surgery and the duration of symptoms are of no prognostic significance. Surgical excision with an oncologically wide margin provides the best prospect both for cure and local control in these patients.

Populations of NGF-dependent neurones differ in their requirement for BAX to undergo apoptosis in the absence of NGF/TrkA signalling in vivo

Reports that apoptosis within populations of neurotrophin-dependent neurones is virtually eliminated in BAX-deficient mice and that BAX-deficient neurones survive indefinitely in culture without neurotrophins have led to the view that BAX is required for the death of neurotrophin-deprived neurones. To further examine this assertion in vivo, we have studied two populations of NGF-dependent neurones during the period of naturally occurring neuronal death in mice that lack BAX, NGF or the NGF receptor TrkA, alone and in combination. In the superior cervical ganglion (SCG), naturally occurring neuronal death and the massive loss of neurones that took place in the absence of NGF or TrkA were completely prevented by elimination of BAX. However, in the trigeminal ganglion, naturally occurring neuronal death was only partly abrogated by the elimination of BAX, and although the massive neuronal death that took place in this ganglion in the absence of NGF or TrkA was initially delayed in embryos lacking BAX, this subsequently occurred unabated. Accordingly, BAX-deficient neurones survived in defined without NGF whereas BAX-deficient trigeminal neurones died in the absence of NGF. These results indicate that whereas BAX is required for the death of SCG neurones during normal development and when these neurones are deprived of NGF/TrkA signalling in vivo, the death of trigeminal ganglion neurones occurs independently of BAX when they are deprived of NGF/TrkA signalling. We conclude that BAX is not universally required for neuronal death induced by neurotrophin deprivation, but that there are major differences for the requirement for BAX among different populations of NGF-dependent neurones.

TNFalpha contributes to the death of NGF-dependent neurons during development

Many sympathetic and sensory neurons depend on a supply of nerve growth factor (NGF) from their targets during development, and neurons that fail to obtain sufficient NGF die by apoptosis. Here we show that tumor necrosis factor alpha (TNFalpha) is involved in bringing about the death of NGF-deprived neurons. Function-blocking antibodies against either TNFalpha or TNF receptor 1 (TNFR1) rescued many sympathetic and sensory neurons following NGF deprivation in vitro. Fewer sympathetic and sensory neurons died during the phase of naturally occurring neuronal death in TNF-deficient embryos, and neurons from these embryos survived in culture better than wild-type neurons. These neurons coexpress TNFalpha and TNFR1 during this stage of development, suggesting that TNFalpha acts by an autocrine loop.

Death of adolescents: parental grief and coping strategies

The death of an adolescent is a particularly complex issue. The process of grieving and coping can be complicated by the tension that may have existed in the parent/child relationship because of the conflict in terms of personal ideology at this stage in the adolescent's development. As a result, parents of adolescent children who die have the potential to experience abnormal grief reactions. Parental coping strategies vary according to the mode of death and outlook adopted by the parents, although some studies suggest parents bereaved of adolescent children do not exhibit marked difference in grieving or coping in comparison to other groups of parents. Healthcare professionals must recognize the specific and special needs of this parent group, and provide appropriate support to minimize the risk of harmful sequelae that may occur as a result of inappropriate and insensitive care.

Neoantigen formation and clastogenic action of HCFC-123 and perchloroethylene in human MCL-5 cells

In this study, the metabolic activation of 2,2-dichloro-1,1,1-trifluoroethane (hydrochlorofluorocarbons-123, HCFC-123), halothane or 1,1-dichloro-1-fluoroethane (HCFC-141b) was compared to that of perchloroethylene, using lymphoblastoma derived cell lines expressing human CYP1A1, CYP1A2, CYP2E1, CYP2A6 and CYP3A4 (MCL-5 cells). A dose dependent increase in micronucleus formation was detected over a nominal concentration range of 0.05-2 mM for HCFC-123 and halothane, but this was not seen with HCFC-141b. No dose response for HCFC-123 was seen in a control cHo1 cell line not expressing this cytochrome P450's. Cell lines expressing individual human cytochrome P-450 (CYP) forms were also used to define the enzymes responsible for the clastogenic events and to investigate the formation of immunoreactive protein by microsomal fractions. It was shown that CYP2E1 or CYP2B6 catalysed the clastogenic response, but CYP2D6, CYP3A4, CYP1A2 or CYP1A1 all appeared to be inactive. The formation of neoantigenic trifluoroacetylated protein adducts by microsomal mixtures incubated with HCFC-123 and NADPH was catalysed primarily by CYP2E1 and to a lesser extent by CYP2C19, whereas, only trace levels of immunoreactive protein were seen with microsomes expressing CYP2B6 or CYP2C8. With perchloroethylene as a substrate, the extent of activation was low in comparison with HCFC-123, as judged by the absence of micronuclei formation in the MCL-5 cell line and the weak immunoreactivity of proteins following Western blotting. CYP1A2, CYP2B6 and CYP2C8 appeared to be responsible for perchloroethylene immunoreactivity and in contrast to the findings with the HCFC's, no activation of perchloroethylene by CYP2E1 could be detected. These results show that even though both saturated and unsaturated halocarbons can result in neoantigen formation, there is a marked difference in the specificity of the CYP enzymes involved in their metabolic activation.

Multiple effects of artemin on sympathetic neurone generation, survival and growth

To define the role of artemin in sympathetic neurone development, we have studied the effect of artemin on the generation, survival and growth of sympathetic neurones in low-density dissociated cultures of mouse cervical and thoracic paravertebral sympathetic ganglia at stages throughout embryonic and postnatal development. Artemin promoted the proliferation of sympathetic neuroblasts and increased the generation of new neurones in cultures established from E12 to E14 ganglia. Artemin also exerted a transient survival-promoting action on newly generated neurones during these early stages of development. Between E16 and P8, artemin exerted no effect on survival, but by P12, as sympathetic neurones begin to acquire neurotrophic factor independent survival, artemin once again enhanced survival, and by P20 it promoted survival as effectively as nerve growth factor (NGF). During this late period of development, artemin also enhanced the growth of neurites from cultured neurones more effectively than NGF. Confirming the physiological relevance of the mitogenic action of artemin on cultured neuroblasts, there was a marked reduction in the rate of neuroblast proliferation in the sympathetic ganglia of mice lacking the GFRα3 subunit of the artemin receptor. These results indicate that artemin exerts several distinct effects on the generation, survival and growth of sympathetic neurones at different stages of development.

Role of PI 3-kinase, Akt and Bcl-2-related proteins in sustaining the survival of neurotrophic factor-independent adult sympathetic neurons

By adulthood, sympathetic neurons have lost dependence on NGF and NT-3 and are able to survive in culture without added neurotrophic factors. To understand the molecular mechanisms that sustain adult neurons, we established low density, glial cell-free cultures of 12-wk rat superior cervical ganglion neurons and manipulated the function and/or expression of key proteins implicated in regulating cell survival. Pharmacological inhibition of PI 3-kinase with LY294002 or Wortmannin killed these neurons, as did dominant-negative Class IA PI 3-kinase, overexpression of Rukl (a natural inhibitor of Class IA PI 3-kinase), and dominant-negative Akt/PKB (a downstream effector of PI 3-kinase). Phospho-Akt was detectable in adult sympathetic neurons grown without neurotrophic factors and this was lost upon PI 3-kinase inhibition. The neurons died by a caspase-dependent mechanism after inhibition of PI 3-kinase, and were also killed by antisense Bcl-xL and antisense Bcl-2 or by overexpression of Bcl-xS, Bad, and Bax. These results demonstrate that PI 3-kinase/Akt signaling and the expression of antiapoptotic members of the Bcl-2 family are required to sustain the survival of adult sympathetic neurons.

Role of STAT3 and PI 3-kinase/Akt in mediating the survival actions of cytokines on sensory neurons

The binding of cytokines to the gp130 receptor activates the STAT3, MEK/MAPK, and PI3K/Akt signalling pathways. To assess the relative importance of these pathways in promoting the survival of cytokine-dependent neurons, we conditionally inactivated STAT3 in mice and inhibited MEK, PI3K, and Akt in cultured neurons using pharmacological reagents and by expressing specific inhibitory proteins. Inactivation of STAT3 enhanced the death of the cytokine-dependent sensory neurons of the nodose ganglion in vivo and substantially reduced the response of these neurons to CNTF and LIF in vitro. LY294002, an inhibitor of PI3K, but not PD98059, an inhibitor of MEK, markedly reduced the response of these neurons to CNTF, as did dominant-negative PI3K, dominant-negative Akt, and overexpression of Ruk (a natural PI3K inhibitor). These results demonstrate that STAT3 and PI3K/Akt signalling play major roles in mediating the survival response of neurons to cytokines.

Imaging recurrent parosteal osteosarcoma

The aim of this study was to document the imaging features of recurrent parosteal osteosarcoma. The clinical and imaging records of 33 patients with a parosteal osteosarcoma referred to an orthopaedic oncology service over a 17-year period were retrospectively reviewed. The mode of identification of locally recurrent tumour was noted, together with the management and clinical outcome. Five patients developed a local recurrence of their parosteal osteosarcoma ranging from 6 months to 10 years after initial surgery. In 4 patients the recurrence was first suspected clinically due to the development of a mass. In the fifth patient recurrence was first detected on routine follow-up radiography. In 4 patients the recurrence could be identified on radiography as a mineralized mass. All the recurrences were readily identified on MR imaging, despite artefacts from prostheses. The recurrences were also evident in the 3 cases in which bone scintigraphy was performed. Local recurrence of parosteal osteosarcoma is adequately detected with a combination of clinical examination and conventional radiography. MR imaging is required to stage local recurrence or where radiography has failed to confirm clinically suspected recurrence. The routine use of MR imaging to follow-up patients is of doubtful value because of the frequently long time between initial surgery and relapse.

Coupling Met to specific pathways results in distinct developmental outcomes

Receptor tyrosine kinases (RTKs) mediate distinct biological responses by stimulating similar intracellular signaling pathways. Whether the specificity of the response is determined by qualitative or quantitative differences in signaling output is not known. We addressed this question in vivo by replacing the multifunctional docking sites of Met, the receptor for hepatocyte growth factor, with specific binding motifs for phosphatidylinositol-3 kinase, Src tyrosine kinase, or Grb2 (Met(2P), Met(2S), and Met(2G), respectively). All three mutants retained normal signaling through the multiadaptor Gab1, but differentially recruited specific effectors. While Met(2G) mice developed normally, Met(2P) and Met(2S) mice were loss-of-function mutants displaying different phenotypes and rescue of distinct tissues. These data indicate that RTK-mediated activation of specific signaling pathways is required to fulfill cell-specific functions in vivo.

Metal-containing lymph nodes following prosthetic replacement of osseous malignancy: potential role of MR imaging in characterisation

The identification of regional lymphadenopathy in patients with bone malignancy treated by excision and insertion of a prosthesis usually indicates metastatic disease. We present two cases in which the lymphadenopathy was due to an uncommon but well-recognized foreign body reaction. This is secondary to the lymphatic uptake of metal debris shed by the prosthesis. In one case the metal within the excised lymph node could be demonstrated on in vitro MR imaging and in retrospect on the original in vivo scans. This condition should be considered when undertaking an MR examination in patients with bone malignancy treated by prosthetic replacement in whom there is a clinical suspicion of metastatic spread to the regional lymph nodes.

MR imaging of pseudosarcoma in Paget's disease of bone: a report of two cases

Pseudosarcoma is a rare manifestation of Paget's disease of bone. We report the MR imaging of two cases highlighting the difficulties in diagnosis. One of the cases is the first time this condition has been described outside the long bones of the lower limb.

Reciprocal developmental changes in the roles of Bcl-w and Bcl-x(L) in regulating sensory neuron survival

We have compared the roles of two anti-apoptotic members of the Bcl2 family, Bcl-w and Bcl-x(L), in regulating the survival of sensory neurons during development. We used microinjection to introduce expression plasmids containing Bcl-w and Bcl-x(L) cDNAs in the sense and antisense orientations into the nuclei of BDNF-dependent nodose neurons and NGF-dependent trigeminal neurons at stages during and after the period of naturally occurring neuronal death. Whilst overexpression of either protein promoted neuronal survival in the absence of neurotrophins and microinjection of antisense constructs reduced neuronal survival in the presence of neurotrophins, the magnitude of these effects changed with age. Whereas Bcl-w overexpression became more effective in promoting neuronal survival with age, Bcl-x(L) overexpression became less effective, and whereas antisense Bcl-w became much more effective in killing neurotrophin-supplemented neurons with age, antisense Bcl-x(L) became much less effective in killing these neurons. There was a marked increased in Bcl-w mRNA and Bcl-w immunoreactive neurons and a decrease in Bcl-x(L) mRNA and Bcl-x(L) immunoreactive neurons in the trigeminal and nodose ganglia over this period of development. Our results demonstrate that both Bcl-w and Bcl-x(L)play an important anti-apoptotic role in regulating the survival of NGF- and BDNF-dependent neurons, and that reciprocal changes occur in the relative importance of these proteins with age. Whereas Bcl-x(L) plays a more important role during the period of naturally occurring neuronal death, Bcl-w plays a more important role at later stages.

Imaging in skeletal paediatric oncology

The prognosis for the child presenting with a bone sarcoma has improved dramatically with the introduction of adjuvent chemotherapy. As a result the majority of patients can now expect to undergo limb salvage surgery. The role of imaging in the management of the child presenting with a suspected sarcoma is presented. This commences with tumour detection, through diagnosis and surgical staging, re-staging with assessment of response to chemotherapy and follow-up surveillance for the development of local recurrence and/or metastases. The importance of the multidisciplinary approach to the management of bone sarcomas is emphasised.

Chicken synucleins: cloning and expression in the developing embryo

Synucleins comprise a family of small intracellular proteins that have recently attracted considerable attention because of their involvement in human diseases. Mutations of alpha-synuclein has been found in several families with hereditary early-onset Parkinson's disease and accumulation of this protein in characteristic cytoplasmic inclusions is a pathohistological hallmark of several neurodegenerative diseases that have been recently classified as 'alpha;-synucleinopathies' (reviewed in Brain Res. Bull. 50 (1999) 465; J. Neurosci. Res. 58 (1999) 120; Philos. Trans. R. Soc. Lond. Biol. Sci. 354 (1999) 1101; Brain Pathol. 9 (1999) 733). Aggregates of beta-synuclein and persyn (gamma-synuclein) also have been found in dystrophic neurites associated with Parkinson's and other neurodegenerative diseases (Proc. Natl. Acad. Sci. USA 96 (1999) 13450; and our unpublished observations). Moreover, persyn has been implicated in malignization of breast tumours (Cancer Res. 57 (1997) 759; Cancer Res. 59 (1999) 742; Hum. Mol. Genet. 7 (1998) 1417). All synucleins have distinct, although overlapping, patterns of expression in the embryonic, postnatal and adult mammalian nervous systems, suggesting important, although still not clear, biological functions in neuronal developing. Chicken embryo is a unique object for developmental studies that allows in vivo manipulations not always possible for mammalian embryos. Studies of synucleins expression in this model system could shed light on their functions in the developing nervous system. We cloned three chicken synucleins from the embryonic neural cDNA libraries and studied their expression in normal chicken embryonic tissues by Northern and in situ hybridization with specific probes. Our results demonstrate that primary structures and expression patterns of synucleins are similar in birds and mammals, suggesting that conserved function of synucleins is important for embryonic development of vertebrates.

Synovial sarcoma arising in association with a popliteal cyst

Synovial sarcoma is a relatively common soft tissue sarcoma particularly in the adolescent and young adult. We report an unusual case of a synovial sarcoma arising within a popliteal cyst in a 13-year-old female presenting with bilateral popliteal cysts. MR imaging demonstrated the cyst with evidence of subacute haemorrhage and a discrete nodule of tumour.