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.

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.

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.

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.

Surgical management of pelvic and extremity osteosarcoma.

Between 60-80% of all patients with osteosarcomas of the pelvis and the extremities can now be safely treated with limb-sparing surgery. Results (as defined by rates of local recurrence, overall survival, and function) are equal to or better than those associated with amputation. Successful use of limb-sparing procedures, however, depends on a well-developed surgical plan. An understanding of the biologic behavior and growth patterns of these lesions is fundamental. Staging of the primary tumor must involve a full complement of imaging modalities, including plain radiography, bone scintigraphy, computerized axial tomography (CAT), magnetic resonance imaging (MRI), and angiography. The biopsy must be well placed to reduce the possibility of tissue contamination, which is a common reason for amputation. Restaging is necessary before surgery for patients who have undergone neoadjuvant therapy; there is recent evidence that preoperative therapy may make limb-sparing surgery possible in more than 50% of patients who otherwise would have required amputation. Relative contraindications to limb-sparing surgery include major involvement of the neurovascular bundle, pathologic fracture, inappropriate biopsy site, infection, immature skeletal age, and extensive muscle involvement. Each of these factors is relative, and patient selection decisions must be made on an individual basis. Limb-sparing surgery consists of the following three phases: tumor resection, skeletal reconstruction, and soft tissue and muscle transfers. The range of reconstruction techniques has been broadened by developments in bioengineering. Among the more commonly used techniques are custom endoprostheses and allograft replacements. Future progress in induction regimens and reconstructive techniques will undoubtedly enable limb-sparing surgery to be a satisfactory alternative to amputation in even more patients.

Liposarcoma of the extremities: MR and CT findings in the histologic subtypes.

The findings on images of liposarcomas of the extremities in 48 patients (26 men and 22 women aged 20-85 years) were reviewed to correlate the histologic subtypes with radiologic appearance. Computed tomographic scans were obtained in 36 patients; magnetic resonance (MR) images, in 27 patients. The study group had 19 myxoid, 12 well-differentiated, nine round cell, and eight pleomorphic liposarcomas. Well-differentiated liposarcomas were predominantly composed of fat, typically with thick septa, which were hyperintense on T2-weighted spin-echo MR images. The heterogeneity of tumor helped differentiate tumor subtypes. Eleven of 19 myxoid tumors were mildly heterogeneous. Round cell and pleomorphic subtypes, which tend to be aggressive, were generally heterogeneous. Well-differentiated liposarcomas may be confidently differentiated from other subtypes of liposarcoma. Except for the well-differentiated subtypes, liposarcomas often contain no fat. Moderate to marked heterogeneity is common in high-grade liposarcomas; myxoid liposarcomas tend to be homogeneous and may mimic cysts.