Nonneoplastic lesions that simulate primary tumors of bone.

CONTEXT: The skeletal system may be affected by a variety of nonneoplastic lesions, which may potentially be confused with primary bone tumors on clinical, radiologic, and pathologic grounds. These conditions include fractures, infections, and reactive and degenerative processes, as well as an array of quasineoplastic entities, such as intramedullary cystic lesions like unicameral and aneurysmal bone cysts; fibro-osseous lesions, such as fibrous dysplasia; and exophytic entities, like osteochondromas. OBJECTIVE: To review clinical, radiographic, and histologic features of nonneoplastic lesions of bone, discussing the difficulties in diagnosis and the differential diagnosis with primary neoplasms of bone. DATA SOURCES: The sources include the more relevant medical literature on the different subjects and case-derived material. CONCLUSIONS: Because many nonneoplastic bone lesions may require biopsy or resection, the general surgical pathologist must be familiar with these lesions and be aware that review of hematoxylin-eosin slides is only one of the many steps in the diagnostic process, which also includes review of imaging studies and all available clinical information. Morphologic analysis disconnected from the clinical and radiographic context may lead to misinterpretation.

Atypical diaphyseal femoral fractures--new aspects.

Post menopausal osteoporotic fractures are a major public health concern worldwide with oral bisphosphonates favored for their prevention and treatment. Recent interest has centered on clinically observed, unusually sited femoral diaphyseal fractures, particularly attributed to alendronate. Their imaging presentations on routine radiographs, alternate imaging modalities, and associated pitfalls in nine fractures in six patients are selectively illustrated by seven fractures in four patients that serve to emphasize the following: (1) Bisphosphonates other than alendronate have been used for treating various bone diseases in children and men as well as osteoporotic women. (2) Effects may differ with each bisphosphonate's route of administration and prolongation of activity, despite discontinuation. Prior investigations and theoretical mechanisms of bisphosphonates as a class rather than with a specific alendronate association are reviewed to provide a broader basis for evaluating their recently observed clinical and radiographic complications.

18Fluoro-deoxyglucose positron emission tomography evaluation of benign versus malignant osteochondromas: preliminary observations.

OBJECTIVE: To determine the contribution of 18fluoro-deoxyglucose positron emission tomography (18FDG PET) in distinguishing benign from malignant osteochondromas. MATERIALS AND METHODS: From 2000 to 2004, 10 patients (4 females, 6 males, 12 to 64 years old) with osteochondromas were referred for whole body PET by clinicians for metabolic evaluation before planned surgery for pain or cosmesis. Two PET readers and 1 pathologist, blinded to their diagnoses and imaging studies (except for radiographs), correlated results post surgery. The PET average and maximum standard uptake value (SUV) generated by computer for Regions of Interest and correlated with radiographs, were based on axial 3.37 mm thick, 3 x 3 mm pixel images. Since SUVs vary from site to site depending on scanning devices and techniques, a 2.0 maximum cutoff SUV separated benign and malignant osteochondromas based on our standard protocols and specific equipment (Siemens Ecat Exact Knoxville, Tenn) used with our prior oncological studies. RESULTS: Results showed that no definitive statistical conclusions could be drawn due to the small number of patients involved, but they were, nevertheless, deemed promising. CONCLUSIONS: The 18FDG whole body PET aided the identification of malignant osteochondromas, their local recurrence and metastases by both displaying and quantifying their metabolic activity. Although the current study is limited by a small cohort, which precludes statistical analysis, additional experience with PET analysis of osteochondromas may further support its value as a physiological parameter supplementing anatomically based imaging modalities most often used for their evaluation.

Radiology of shoulder prostheses.

This article is chiefly limited to the routine radiographic evaluation of shoulder arthroplasties and guidelines to their interpretation. Other imaging modalities for the evaluation of joint replacements are discussed elsewhere in this issue. The basic types of shoulder reconstructions and some of the shoulder replacement designs in previous and current use at The New York Orthopedic Hospital at Columbia Presbyterian Medical Center are illustrated, along with the indications and contraindications of the various types of reconstructions. Their complications and pertinent anatomy are included.

Extranodal Rosai-Dorfman disease of bone, subcutaneous tissue and paranasal sinus mucosa with a review of its pathogenesis.

We report an unusual case of extranodal Rosai-Dorfman disease presenting in a 36-year-old man with lesions of bone, subcutaneous tissue of the arm and maxillary sinus mucosa unassociated with lymphadenopathy or systemic symptoms. These lesions appeared metachronously within a 6-month period. The diagnostic light microscopic and immunohistochemical findings and pathogenesis of this interesting disease are discussed.

18FDG-PET applications for cartilage neoplasms.

OBJECTIVE: To assess the value of [18F]fluoro-2-deoxy-D-glucose positron emission tomography (18FDG-PET) in defining aggressive cartilage neoplasms, particularly those with problematic or borderline histologic, imaging and clinical characteristics. DESIGN AND PATIENTS: From 2000 to 2003, 29 cartilage lesions were studied with whole-body 18FDG-PET scans (Siemens Ecat Exact, Knoxville, Tenn.). Analyses of data in 20 females and nine males, 11-85 years old, were based on maximum standard uptake values (SUVs) in regions of interest (ROIs) on axial 3.37 mm thick, 3x3 pixel images. A statistically significant maximum SUV cutoff of 2.0 was used to distinguish benign from malignant cartilage neoplasms and correlated with the postoperative histopathologic findings. RESULTS: In 26 operated cases the overall sensitivity of whole-body 18FDG-PET in separating benign and malignant lesions was 90.9% (10/11), specificity 100% (18/18) and accuracy 96.6%. CONCLUSIONS: Whole-body 18FDG-PET is a valuable adjunct in identifying primary, recurrent and metastatic cartilage malignancies. It supplements classic histology and morphologic imaging with functional data which may facilitate management in individual cases.

MRI of seemingly isolated greater trochanteric fractures.

OBJECTIVE: The objective of this article is to show that greater trochanteric fractures commonly perceived on routine radiographs as isolated are often neither isolated nor minor and that MR images can serve as a basis for more informed treatment by revealing the actual extent of such fractures in acute posttraumatic settings. CONCLUSION: A pitfall in diagnosing seemingly isolated greater trochanteric fractures on routinely used imaging techniques lies in the fact that the injuries usually involve a large anatomic area. In our experience, MRI more accurately defines the true geographic extent of greater trochanteric fractures sustained through acute trauma than do radiography and bone scintigraphy and thus could provide a more reliable basis for anticipating complications and for planning appropriate treatment.

Classification of intertrochanteric fractures with computed tomography: a study of intraobserver and interobserver variability and prognostic value.

The purpose of this prospective study was to determine the level of interobserver and intraobserver agreement among orthopedic surgeons and radiologists when computed tomography (CT) scans are used with plain radiographs to evaluate intertrochanteric fractures. In addition, the prognostic value of current classifications systems concerning quality of life was evaluated. Sixty-one patients who presented with intertrochanteric fractures received open reduction and internal fixation with compression hip screw. Three orthopedic surgeons and 2 radiologists independently classified the fractures according to 2 systems: Evans-Jensen and AO (Arbeitsgemeinschaft für Osteo-synthesefragen). Fractures were initially graded with plain radiographs and then again in conjunction with CT. Results were analyzed using the (kappa) kappa coefficient. The 36-item Short-Form Health Survey was administered at baseline, 3 months, and 1 year, and results were correlated with fracture grade. Mean kappa coefficients when comparing radiography alone with radiography and CT scan were 0.63 for the AO system and 0.59 for the Evans-Jensen system. Both represent "fair" agreements. Mean overall interobserver kappa coefficients were 0.67 for radiologists and 0.57 for orthopedic surgeons. Radiologists also had higher intraobserver kappa coefficients. No significant relationships were found between follow-up Short Form Health Survey results and intraoperative grading of fractures. When these classification schemes are compared, interobserver agreement does not appear to change dramatically when information from CT scans is added. This may suggest that (1) more data have been provided by CT with greater possibilities for misinterpretation and (2) these classification schemes may not be comprehensive in describing fracture pattern and displacement. Finally, both systems failed to provide any prognostic value.

18FDG PET scanning of benign and malignant musculoskeletal lesions.

OBJECTIVE: To describe the technique, applications and advantages of (18)FDG PET scanning in detection, analysis and management of musculoskeletal lesions. DESIGN AND PATIENTS: Forty-five patients (19 males,26 females) aged 9 to 81 years had radiographs, routine radionuclide scans, CT and/or MRI of clinically suspected active benign or malignant musculoskeletal lesions. (18)FDG scans with a Siemens ECAT EXACT 921 dedicated PET unit (Knoxville, Tenn.) and FWH=6 mm images acquired as a 5-6 bed examination (6 min emission and 4 min transmission) used OSEM iterative reconstruction with segmented transmission attenuation correction and a Gaussian filter (cutoff 6.7 mm). Region of interest (ROI) 3x3 pixel image analysis based on transverse whole body images (slice thickness 3.37 mm) generated Maximum Standard Uptake Values (Max SUV) with a cutoff of 2.0 used to distinguish benign and malignant lesions. RESULTS: Thirty-nine studies were available for SUV ROI analysis. Overall sensitivity for differentiating malignant from benign osseous and non-osseous lesions was 91.7% (22/24), overall specificity was 100% (11/11) with an accuracy of 91.7%. All aggressive lesions had a Max SUV >2.0. Data separating benign from malignant lesions and aggressive from benign lesions were statistically significant ( P<0.001) in both categories. There was no statistically significant difference in distinguishing aggressive from malignant lesions ( P, ns). CONCLUSION: (18)FDG PET contributes unique information regarding metabolism of musculoskeletal lesions. By supplying a physiologic basis for more informed treatment and management, it influences prognosis and survival. Moreover, since residual, recurrent or metastatic tumors can be simultaneously documented on a single whole body scan, PET may theoretically prove to be cost-effective.