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Biomedical subjects

A M Davies

Publications and source records attributed to A M Davies.

At least 19 recordsLinked to original sources
PubMed2004

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.

Adult↗
PubMed2004

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.

Bone Neoplasms↗
PubMed2004

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.

Acute Disease↗
PubMed2004

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.

Adult↗
PubMed2004

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.

Aged↗
PubMed2004

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.

Adolescent↗
PubMed2004

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.

Anemia, Sickle Cell↗
PubMed2003

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.

Adolescent↗
PubMed2003

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.

Adolescent↗
PubMed2003

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.

Adult↗
PubMed2002

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.

Bone Neoplasms↗
PubMed2002

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.

Adult↗
PubMed2002

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.

Adult↗
PubMed2002

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).

Female↗
PubMed2002

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.

Bone Neoplasms↗
PubMed2002

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.

Adolescent↗