Imaging of spindle cell lipoma.

AIM: To review the evaluation, diagnosis, and treatment of spindle cell lipoma (SCL) with emphasis on the location of these tumours and the spectrum of magnetic resonance imaging (MRI) and computed tomography (CT) appearances. MATERIALS AND METHODS: The MRI and CT findings of 27 histopathologically proven SCLs were evaluated retrospectively. Imaging features evaluated included margins, percentage visible fat, MRI signal characteristics, oedema, and contrast enhancement patterns. RESULTS: Patient ages ranged from 18 to 80 years with an average age of 56.5 years. Men were affected twice as frequently as women (M=18, F=9). SCLs ranged in size from 2 to 10 cm, with an average greatest dimension of 5.5 cm. Five lesions (19%) contained no visible fat on CT or MRI, and the leading differential diagnosis of high-grade soft-tissue sarcoma diagnosis was suggested by referring surgeons. Five lesions (19%) had <50% fatty areas, nine lesions (52%) demonstrated >50% but <90% fat at MRI or CT. Only three of 25 lesions (12%) had an appearance of a typical lipoma on unenhanced MRI sequences. All SCLs that were imaged with contrast medium (n = 18) demonstrated some degree of enhancement, with eight (44%) showing marked enhancement, four (22%) showing moderate, and six (33%) minimal enhancement. CONCLUSION: SCLs have considerably variable imaging appearances and may have minimal or no visible fat at MRI or CT. Imaging features may make it difficult to distinguish this benign tumour from a potentially higher-grade malignant tumour.

Determinants of learning to perform spinal anaesthesia: a pilot study.

BACKGROUND AND OBJECTIVE: This study examined attitudes and views held by stakeholders regarding their experience of training in spinal anaesthesia. The aim was to identify key factors related to learning and teaching processes which were perceived to influence the acquisition of competence in spinal anaesthesia. METHODS: The study was carried out at a busy acute tertiary referral teaching hospital over a period of 1 yr. It applied a qualitative research approach in three phases, namely (i) completion of preliminary questionnaires, (ii) completion of focused questionnaires and (iii) focus group discussions. RESULTS: Five factors were perceived to be critical 'determinants of learning': (i) the existence of a formal, structured training programme; (ii) time constraints/theatre efficiency; (iii) trainer-trainee interaction; (iv) patient safety/trainee/trainer stressors; and (v) visualization of the anatomy and procedure. CONCLUSION: The study highlighted the need for a formal and structured training programme in spinal anaesthesia, through which many of the undesirable and discouraging factors (such as stress, adverse trainer-trainee interaction and time constraints) identified in the study could be minimized. Further studies are needed to validate the results in other hospital settings, as well as to define the relative importance of each of the proposed determinants and their interrelationships.

Heterogeneous expression of melanoma antigen (hMAGE) mRNA in mesenchymal neoplasia.

Recommendations have been advanced recently for the use of cancer/testis (CT) immunotherapy against sarcomas. CT antigens are encoded by cancer-germline genes (e.g., hMAGE family) that are expressed in tumors and male germline cells but typically not in normal tissues. At present, little information is available regarding CT expression in mesenchymal neoplasms, and it remains uncertain whether CT immunotherapy will serve as a viable alternative or adjunct to current sarcoma therapies involving resection, followed by adjuvant radiotherapy and/or chemotherapy. In this study, hMAGEA2, hMAGEA3, hMAGEA4, and hMAGEC1 mRNA content in 21 benign mesenchymal tumors (representing seven histotypes) and 28 primary sarcomas (10 histotypes) was inventoried using real-time-PCR and then compared against hMAGE mRNA expression in non-sarcomatous malignancies, three cell lines, and muscle. hMAGEA2, hMAGEA3, and hMAGEC1 transcripts were infrequent in mesenchymal tissues in general, whereas hMAGEA4 mRNA was present in 84% of all mesenchymal tumors, 100% of non-sarcomatous tumors, all three cell lines, and in four of five muscle samples. Although hMAGEA4 mRNA was detected in four of five muscle preparations, there was no indication that the mRNA was translated into protein. The presence of hMAGEA4 mRNA in muscle, plus the inconsistent and infrequent occurrence of hMAGEA2, hMAGEA3, and hMAGEC1 mRNA within and among mesenchymal tumor histotypes, makes these four hMAGE antigens unlikely candidates for sarcoma-specific immunotherapy.

Incidence, location, and diagnostic evaluation of metastatic bone disease.

Metastatic carcinoma is the most common malignancy of bone. The clinical presentation of patients with skeletal metastasis is variable. When asked to evaluate a patient with a pathologic lesion or unexplained bone pain, the orthopedic surgeon should follow a logical sequence of steps in evaluating the patient with suspected metastasis to optimize care and avoid complications. In the majority of cases, a systematic approach to the patient with skeletal metastasis leads to the correct diagnosis.

A comparison of mechanical strength of the femoral neck following locked intramedullary nailing using oblique versus transverse proximal screws.

OBJECTIVE: The objective of the present study was to determine whether the 130-degree oblique or transverse proximal locking technique significantly enhances or diminishes the strength of the intramedullary nail-to-bone construct in a "stancelike" loading configuration. DESIGN: Six paired fresh frozen femora were randomized to locked intramedullary nailing with either the 130-degree proximal locking technique or the transverse locking technique and tested in axial compressive loading. Torsion, shear, and impact loading were not tested. PATIENTS/PARTICIPANTS: Six paired adult fresh frozen cadavers. INTERVENTION: An unreamed eleven-millimeter by thirty-eight-centimeter intramedullary nail was placed under direct visualization in each femur. Proximal locking was randomly performed on each pair with either two transverse screws or a single oblique screw. Each femur was loaded to failure at a rate of 50.8 millimeters per minute (two inches per minute) by using an Instron tensiometer. Radiographs after nail insertion and after failure were obtained. MAIN OUTCOME MEASURES: Load to fracture and fracture pattern. RESULTS: A significant difference between load to fracture was observed across femora of different donors (p < 0.001). No significant difference was observed in paired femora from the same donor when using either 130-degree or transverse proximal locking (p > 0.05). This result was based on nonanatomical axial loading that approximated loading during stance, without hip abductor loads to help stabilize the femur. CONCLUSION: Neither technique preferentially predisposed the construct to failure for the loading pattern tested. The mode of failure was the same in all cases, with failure beginning at the nail insertion site.

Clinical and radiological aspects of idiopathic diabetic muscle infarction. Rational approach to diagnosis and treatment.

The systemic effects of diabetes mellitus are well recognised. The heart, kidney, central and peripheral nervous systems, and the distal parts of the limbs are often the site of end-organ damage resulting from ischaemia. Infarction of large muscle groups in the limb, not associated with gangrene, is uncommon. There have been few reported cases other than radiological descriptions of diabetic muscle infarcts. While previous reports have illustrated some of the clinical and radiological characteristics of this condition, the paucity of published cases makes it difficult to determine the most appropriate methods of diagnosis and treatment. During a five-year period we treated 14 patients with diabetes mellitus, aged from 32 to 59 years, who were referred to a musculoskeletal oncology service for suspected soft-tissue sarcoma, but were subsequently found to have a diabetic muscle infarct. Closed needle biopsy was performed in 13 without complications. In 12 patients, the symptoms resolved without surgical treatment.

Muscle infarction in patients with diabetes mellitus: MR imaging findings.

PURPOSE: To describe the magnetic resonance (MR) imaging findings in diabetic patients with muscle infarction and to describe commonly associated clinical features. MATERIALS AND METHODS: The MR imaging studies of 21 patients with diabetic muscle infarction were reviewed retrospectively. Of the 21 patients, 12 were women, and nine were men; the mean age was 48 years (range, 30-77 years). RESULTS: Eight patients had bilateral lower-extremity involvement; six had involvement confined to the right lower extremity and seven to the left. The thigh was involved in 17 patients (81%). One or more of the musculi vastus, the most frequently affected muscle group, were affected in 16 patients (76%). Four patients (19%) had isolated calf involvement. MR imaging studies showed diffuse enlargement of involved muscle groups and partial loss of normal fatty intermuscular septa. MR imaging also allowed identification of areas of subfascial fluid in 16 patients (76%) and subcutaneous edema in 19 patients (90%). MR imaging showed involved muscle groups best with T2-weighted, inversion-recovery, and gadolinium-enhanced sequences, where the infarcted muscles appeared diffusely hyperintense compared with adjacent muscles. Comparison of T2-weighted and gadolinium-enhanced MR images of nine patients showed enlarged, enhancing muscles in all patients and small, focal, rim-enhancing fluid collections in six of nine patients (66%). CONCLUSION: Diabetic muscle infarction is suggested in diabetic patients with sudden onset of severe pain in the thigh or calf muscles who have MR imaging findings of diffuse edema and swelling of multiple thigh and calf muscles (often in more than one compartment).

Biopsy.

Obtaining tissue for diagnosis of bone and soft-tissue tumors is one of the goals of all biopsies. The biopsy, however, must be well planned so as to avoid creating inadvertent tumor spread, thereby compromising the ability to perform limb-sparing resectional surgery.

Begnign bone tumors of childhood.

The diagnosis of a bone tumor in a child can be a source of great anxiety for the patient, the parents, and the treating physician. Fortunately, most bone tumors in children are benign. Although there are a variety of benign bone tumors that affect skeletally immature patients, most have such characteristic clinical and radiographic presentations that the diagnosis can be made with reasonable accuracy without a biopsy. However, some benign bone tumors can simulate a malignant process and may be best handled by referral to a person trained in orthopaedic oncology for additional evaluation. Treatment alternatives are in part related to the Musculoskeletal Tumor Society stage of the lesion. Recurrences of certain lesions, such as aneurysmal bone cysts and osteoblastomas, can be problematic. By becoming familiar with the presentation of the more common benign bone tumors in children, physicians will be able to alleviate fears, establish a diagnosis, and make treatment recommendations in the most effective manner.

AIDS-associated secondary lymphoma of bone: a case report with review of the literature.

Although musculoskeletal lesions are not reported as commonly as pulmonary or central nervous system abnormalities in human immunodeficiency virus (HIV)-positive individuals, a wide variety of osseous and soft-tissue changes are seen in these patients. We describe the case of a 35-year-old injection drug user with acquired immune deficiency syndrome (AIDS) who presented with diffuse adenopathy, lower extremity pain and swelling, subcutaneous nodules, and constitutional symptoms. Radiographic images showed bilateral lytic lesions of the tibia and accompanying soft-tissue masses. Biopsy of the bone and soft-tissue abnormalities established a diagnosis of Burkitt's-like non-Hodgkin's lymphoma (NHL). By recognizing the heterogeneity of AIDS-associated NHL presentations, and the potential clinical overlap between malignancy, infection, and other rheumatologic abnormalities, physicians may obtain appropriate diagnostic studies and offer treatment recommendations.

Myxoid liposarcoma of the retropatellar fat pad.

Soft-tissue sarcomas are rare lesions, and they are occasionally seen by the orthopedic surgeon. We describe the clinical history of a patient with a myxoid liposarcoma that arose from the retropatellar fat pad of the knee. The differential diagnosis of knee masses and the magnetic resonance image characteristics of myxoid liposarcoma are discussed. There are no previous reports of liposarcomas originating from the retropatellar fat pad. Given the consequences of inappropriate biopsy and surgery of suspected benign lesions, it is fundamentally important to adhere to the principles of musculoskeletal oncology in the evaluation of any soft-tissue mass that could be malignant.

Percutaneous transpedicular biopsy of vertebral body lesions.

STUDY DESIGN: This prospective study evaluates the use of transpedicular biopsy in obtaining diagnostic tissue from vertebral body lesions. OBJECTIVE: To report the authors' experience of all (N = 32) percutaneous transpedicular biopsies performed between 1990-1994. SUMMARY OF BACKGROUND DATA: Previous articles have discussed the value of open biopsy of the vertebral body using a Craig needle. A large series of closed percutaneous transpedicular biopsies have not been reported. METHODS: The authors evaluated 32 patients (26 outpatients, six inpatients) who underwent transpedicular biopsy for T1-L4 lesions of the vertebral bodies. None of the tumors had an extraosseous component. Biopsy specimens were obtained from 25 lesions using C-arm fluoroscopy; seven were guided by computed tomography. All biopsies were performed with a 14- to 17-gauge bone biopsy needle. RESULTS: The needle passed through the pedicle into the site of disease in all patients, as confirmed by C-arm fluoroscopy or computed tomography. There were 22 malignancies; four isolated compression fractures, two at T6, one at T7, one at T8; four cases of infection or inflammation; and one case each of Paget's disease and myelofibrosis. Two patients required a second biopsy because the tissue sample was suspicious for lymphoma but not diagnostic. All 26 outpatients were discharged after a 2-hour observation period. There were no complications. CONCLUSION: Transpedicular biopsy of deep vertebral body lesions using a bone biopsy needle under computed tomography or fluoroscopy guidance can be performed safely and efficaciously as an outpatient procedure.

Neuropathy secondary to pigmented villonodular synovitis of the hip.

Pigmented villonodular synovitis is a benign proliferative process of unknown origin that may cause extensive bone and joint destruction. Patients with this condition typically present with symptoms of mild discomfort and associated stiffness of the involved joint; however, the spectrum of presentations is broad. Although pigmented villonodular synovitis begins in, and usually is confined within, a synovium-lined joint, it may extend beyond the joint capsule and present as a soft tissue mass. Three cases of a previously unrecognized presentation of pigmented villonodular synovitis of the hip joint are presented. The authors believe these to be the first reported cases in the English language literature of pigmented villonodular synovitis of the hip seen with femoral or sciatic neuropathy.

Reconstruction using the saddle prosthesis following excision of primary and metastatic periacetabular tumors.

From 1988 to 1991, 17 patients with malignant periacetabular tumors underwent limb-sparing surgery and reconstruction using the saddle prosthesis. There were 8 patients with primary malignant lesions (Group 1), and 9 patients with metastatic or systemic tumor involving the periacetabular pelvis (Group 2). All resections included excision of the acetabulum. Patients ranged in age from 24 to 76 years (average, 59.8 years). Local control was achieved in all patients. Wide margins were obtained in all patients with primary pelvic tumors. Functional outcomes were rated as follows excellent (10), good (2), fair (1), and poor (4). Three patients, all of whom had pulmonary metastasis before surgery, died within 8 months of surgery. Of the remaining 14 patients, 5 patients died between 6 and 28 months after the index procedure. At the end of the followup period, 9 patients were still alive (6 in Group 1 and 3 in Group 2), with a followup period ranging from 15 to 62 months (average, 33.4 months). The overall results for surviving patients were 7 excellent and 2 good results, with no fair or poor results.

Treatment of large subchondral tumors of the knee with cryosurgery and composite reconstruction.

The radiographic and clinical outcomes of 9 patients with large benign aggressive or low-grade malignant periarticular tumors of the knee who were treated with cryosurgery and composite reconstruction (cementation, bone graft, and internal fixation) in lieu of primary resection were analyzed. The minimum followup was 2 years (range, 24-103 months). There were 6 giant cell tumors and a single case each of chondroblastoma, chondrosarcoma, and fibrosarcoma in the study group. Six lesions involved the distal femur and 3 the proximal tibia. Functional outcomes were graded according to the Enneking Modified System for the Functional Evaluation of Tumor and The Knee Rating Scale of The Hospital for Special Surgery. All lesions extended to within 2 mm of the articular surface. Local tumor control was achieved in 8 patients (89%). The single local recurrence was successfully managed with repeat curettage, cryosurgery, cementation, and internal fixation. All 9 patients had excellent functional outcomes according to both evaluation scales.

Malignant fibrous histiocytoma at the site of hip replacement in association with chronic infection.

A case of malignant fibrous histiocytoma that developed at the site of an infected metallic implant is presented. The total hip endoprosthesis was composed of a cobalt-chromium alloy. There was a relatively short latency period (less than 2 years) between the initial surgery and the development of malignancy in this patient. The authors urge development of a tumor registry to discover if the association between hip replacement and malignancy is coincidental.

Giant cell tumor of the tendon sheath: MR findings in nine cases.

OBJECTIVE: The purpose of this study was to determine the MR findings in patients with giant cell tumors of the tendon sheath. MATERIALS AND METHODS: MR imaging findings in nine surgically proved cases of giant cell tumors of the tendon sheath were evaluated on both T1- and T2-weighted images. Of nine lesions, three involved the foot, two involved the thumb, two involved the knee, one involved the proximal part of the tibia, and one involved the proximal part of the femur. RESULTS: All nine lesions were hypointense on T1-weighted images; the signal intensity of most of the tumors was approximately equal to that of skeletal muscle. On the T2-weighted images, three lesions were hypointense relative to skeletal muscle, two lesions were approximately isointense relative to skeletal muscle, and two lesions were slightly hyperintense relative to skeletal muscle but hypointense relative to fat. The remaining two lesions had a more heterogeneous appearance on T2-weighted images. CONCLUSION: On both T1- and T2-weighted images, giant cell tumor of the tendon sheath has a signal intensity similar to that of its pathologic counterpart, pigmented villonodular synovitis. The decreased signal intensity on both T1- and T2-weighted images is an uncommon appearance of extraarticular soft-tissue masses, in particular when they occur in the hands or feet, and this may suggest the diagnosis of giant cell tumor of the tendon sheath.