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.

Survival after induction chemotherapy and surgical resection for high-grade soft tissue sarcoma. Is radiation necessary?

BACKGROUND: Induction chemotherapy can produce dramatic necrosis in sarcomas-raising the question of whether or not radiation is necessary. This study reviews the clinical outcome of a subset of patients with high-grade extremity soft tissue sarcomas (STS) who were treated with induction chemotherapy and surgical resection but without radiation. METHODS: Nonmetastatic, large, high-grade STS of the pelvis and extremities were treated with intra-arterial cisplatin, adriamycin, and, after 1995, ifosfamide. After induction, oncologic resection and histologic evaluation were performed. Good responders with good surgical margins were not treated with radiation. RESULTS: Thirty-three patients, with a median follow-up of 5 years, were included. Limb salvage rate was 94%. Median tumor necrosis was 95%. Four patients developed metastatic disease with three subsequent deaths. Two local recurrences occurred; both patients were salvaged with reresection and adjuvant external beam radiotherapy, although one died of metastatic disease 10 years later. Relapse-free and overall survival is 80% and 88% at 5 and 10 years by Kaplan-Meier analysis. CONCLUSIONS: Intensive induction chemotherapy can be extremely effective for high-grade STS, permitting limb-sparing surgery in lieu of amputation. Radiation may not be necessary if a good response to induction chemotherapy and negative wide margins are achieved. All patients with large, deep, high-grade STS of the extremities should be considered candidates for induction chemotherapy.

Reconstruction of hip stability after proximal and total femur resections.

Dislocation is the most common complication after proximal and total femur endoprosthetic reconstruction. The current study describes a surgical technique of acetabular preservation and reconstruction of the joint capsule and abductor mechanism that recreates joint stability and avoids dislocation. Between 1980 and 1996, 57 patients underwent proximal or total femur resection with endoprosthetic reconstruction. Forty-six patients had primary sarcoma of bone, nine had other bone tumors, and two had metabolic bone disease. The acetabulum was spared and not resurfaced in all patients. Bipolar hemiarthroplasty was performed in 49 patients, and fixed unipolar hemiarthroplasty was performed in eight. Soft tissue reconstruction included Dacron tape capsulorrhaphy over the prosthetic neck, reattachment of the abductor mechanism to the prosthesis, and extracortical bone fixation. The average followup period was 6.5 years (range, 2-18.2 years). Dislocation occurred in only one (1.7%) patient, and aseptic prosthetic loosening occurred in three (5.3%) patients. Four patients with primary bone sarcoma had local recurrence, of whom one required amputation of the limb. The limb salvage rate was 98%. Eighty-one percent of the patients had a good to excellent functional outcome. Acetabular preservation, capsulorrhaphy, and reconstruction of the abductor mechanism recreate hip stability and avoid dislocation after proximal and total femur endoprosthetic reconstruction.

The percutaneous needle biopsy is safe and recommended in the diagnosis of musculoskeletal masses.

BACKGROUND: The purpose of this study was to analyze the role of percutaneous core needle biopsy in the diagnosis of musculoskeletal sarcomas. METHODS: One hundred eighty-five biopsy procedures were performed on 161 musculoskeletal tissue masses suspected of being a sarcoma in 155 patients who underwent subsequent tumor resection. A percutaneous core needle biopsy was performed on all masses either in the clinic or under radiologic guidance. If an adequate diagnosis could not be made on the basis of this biopsy specimen, an open incisional biopsy was performed. RESULTS: One hundred seventy-three core needle biopsy procedures were performed: 90 without radiologic guidance, 55 computed tomography guided, and 28 fluoroscopically guided. Twelve open incisional biopsies were performed. Eighty-three sarcomas, 67 benign mesenchymal tumors, and 11 metastatic epithelial tumors were identified. Analysis of the data reveals that only 7.4% of the masses required open biopsy. In 88.2% of the masses, a single percutaneous biopsy procedure was adequate, and no additional biopsy was necessary. There was a 1.1% rate of complications; none caused a change in the patient's treatment plan. There was a 1.1% rate of major diagnostic errors, none of which ultimately impacted on the patient's outcome. There were no unnecessary amputations. Percutaneous needle biopsy showed a positive predictive value of 100%, a negative predictive value of 82%, a sensitivity of 81.8%, and a specificity of 100%. The accuracy of a single-needle biopsy procedure to identify benign versus malignant lesions, exact grade, and exact pathology was 92.4%, 88.6%, and 72.7%, respectively. CONCLUSIONS: The percutaneous needle biopsy was found to be extremely effective and safe for the diagnosis of musculoskeletal masses. This method allowed 88% of patients with suspected sarcomas to undergo a single-needle biopsy procedure before the initiation of definitive treatment. Patients undergoing percutaneous needle biopsy had lower rates of major diagnostic errors and complications than previously described for open biopsy. Open biopsy offered limited additional information when preceded by a needle biopsy, given that these tumors were difficult to identify even after final resection.

Extraspinal bone and soft-tissue tumors as a cause of sciatica. Clinical diagnosis and recommendations: analysis of 32 cases.

STUDY DESIGN: Between 1982 and 1997, the authors treated 32 patients with sciatica who subsequently were found to have a tumor along the extraspinal course of the sciatic nerve. SUMMARY OF BACKGROUND DATA: Extraspinal compression of the sciatic nerve by a tumor is a rare cause of sciatica. Signs and symptoms overlap those of the more common causes of sciatica (i.e., herniated disc and spinal stenosis). OBJECTIVE: To characterize the unique clinical presentation of these patients and to formulate guidelines that may lead to early diagnosis. METHODS: All pertinent clinical data and studies were reviewed retrospectively, and standard demographic data were collected for analysis. RESULTS: These patients typically sought treatment for an insidious onset of sciatic pain that was constant, progressive, and unresponsive to change in position or bed rest. The mean time to final diagnosis was 11.9 months (median, 6 months). Seventeen patients were able to locate their pain to a specific point along the extraspinal course of the sciatic pain, and a mass was noted in 13 patients. Eighteen of these tumors were in the pelvis, 10 in the thigh, and 4 in the popliteal fossa and calf. CONCLUSIONS: A high index of clinical suspicion is the key to early diagnosis of bone or soft-tissue tumors as a cause of sciatica; special attention should be given to pain pattern, physical examination of the entire course of the sciatic nerve, and selection of proper imaging studies. Routine anteroposterior plain radiography of the pelvis as part of the initial imaging screening process is recommended.

Cryosurgery in the treatment of giant cell tumor. A long-term followup study.

Between 1983 and 1993, 102 patients with giant cell tumor of bone were treated at three institutions. Sixteen patients (15.9%) presented with already having had local recurrence. All patients were treated with thorough curettage of the tumor, burr drilling of the tumor inner walls, and cryotherapy by direct pour technique using liquid nitrogen. The average followup was 6.5 years (range, 4-15 years). The rate of local recurrence in the 86 patients treated primarily with cryosurgery was 2.3% (two patients), and the overall recurrence rate was 7.9% (eight patients). Six of these patients were cured by cryosurgery and two underwent resection. Overall, 100 of 102 patients were cured with cryosurgery. Complications associated with cryosurgery included six (5.9%) pathologic fractures, three (2.9%) cases of partial skin necrosis, and two (1.9%) significant degenerative changes. Overall function was good to excellent in 94 patients (92.2%), moderate in seven patients (6.9%), and poor in one patient (0.9%). Cryosurgery has the advantages of joint preservation, excellent functional outcome, and low recurrence rate when compared with other joint preservation procedures. For these reasons, it is recommended as an adjuvant to curettage for most giant cell tumors of bone.

Delayed reduction of traumatic knee dislocation. A case report and literature review.

Knee dislocation after high energy trauma poses a major challenge to patients and treating physicians. The case presented documents the history and treatment of an unreduced posterior knee dislocation discovered 24 weeks after injury. Delayed surgical reduction was achieved, and satisfactory results were obtained with 22 months of followup of the patient. A detailed review of the literature found no comparable examples of longstanding traumatic dislocations of the knee but shed light on the probable cause for this unusual case. Close clinical followup, even after appropriate initial treatment of knee dislocations, is needed to eliminate similar occurrences.

Fit of the uncemented femoral component and the use of cement influence the strain transfer the femoral cortex.

To determine whether the strain patterns produced in the femoral cortex after uncemented femoral arthroplasty are influenced by the fit of the component and whether these patterns are different from those of cemented components, cortical surface strains of cadaveric femurs subjected to loads simulating single-limb stance were measured before and after the insertion of uncemented, collared, straight-stemmed femoral components. The effects of press fit, loose fit, and precise fit of the components were evaluated and were contrasted to the strain patterns occurring after insertion of cemented femoral components. Strains varied markedly, depending on the fit of the stem of the uncemented femoral component within the isthmus. Nearly normal patterns of femoral strain were produced when the femoral stem was fit precisely at the isthmus, and the proximal femoral strains were similar to those of the intact state. In contrast, press fit and loose fit at the isthmus altered the strain patterns. The proximal medial axial strains were significantly reduced with press fit, to a mean of 39% of normal (p < 0.05), and increased with loose fit, to a mean of 141% of normal (p < 0.05). The prostheses fixed with cement showed a mean reduction in proximal medial axial strains to 33% of normal, which was comparable with press fit uncemented components even though the collar was well seated. Thus, our findings indicated that, in the immediate postoperative period, femoral strain patterns can be influenced by the fit of an uncemented component within the isthmus and by the use of cement.

High assembly strains and femoral fractures produced during insertion of uncemented femoral components. A cadaver study.

The assembly strains produced in cadaver femurs during uncemented femoral arthroplasty were measured using strain gages and photoelastic coatings. Resecting the femoral neck, reaming the canal with power drills, and rasping with an optimal size rasp, as determined by preoperative radiographic templating, produced small assembly strains, up to 300 microstrain. Insertion of an optimal-size prosthesis after preparing the femoral canal with instruments the same size as the prosthesis produced moderate assembly strains, up to 1,000 microstrain. Half a millimeter press-fit of optimal prostheses produced larger assembly strains, up to 2,000 microstrain. Half a millimeter press-fit of a prosthesis that was also one size (1.0 mm) larger than that determined to be optimum produced even larger assembly strains (2,000-6,000 microstrain) and longitudinal linear fractures in the femoral cortex. Insertion of prostheses that were smaller than the rasps produced minimal strains in the femoral cortex. The magnitude of peak strains produced by press-fitting the femoral components and the small amounts of disparity between the size of the recess and the prosthesis necessary to produce these strains show the narrow range of tolerances available to the surgeon. Cementless femoral arthroplasty requires great care in preparing the femoral canal to the appropriate size as determined from preoperative templating, using accurate and precisely toleranced instrumentation and prosthetic components in order to avoid femoral fractures, yet obtain a stable fit.