The Natural History of Benign Bone Tumors of the Extremities in Asymptomatic Children: A Longitudinal Radiographic Study

What Is the Prevalence of Clinically Important Findings Among Incidentally Found Osseous Lesions?

BACKGROUND

Patients with incidentally found musculoskeletal lesions are regularly referred to orthopaedic oncology. Most orthopaedic oncologists understand that many incidental findings are nonaggressive and can be managed nonoperatively. However, the prevalence of clinically important lesions (defined as those indicated for biopsy or treatment, and those found to be malignant) remains unknown. Missing clinically important lesions can result in harm to patients, but needless surveillance may exacerbate patient anxiety about their diagnosis and accrue low-value costs to the payor.

QUESTIONS/PURPOSES

(1) What percentage of patients with incidentally discovered osseous lesions referred to orthopaedic oncology had lesions that were clinically important, defined as those receiving biopsy or treatment or those found to be malignant? (2) Using standardized Medicare reimbursements as a surrogate for payor expense, what is the value of reimbursements accruing to the hospital system for the imaging of incidentally found osseous lesions performed during the initial workup period and during the surveillance period, if indicated?

METHODS

This was a retrospective study of patients referred to orthopaedic oncology for incidentally found osseous lesions at two large academic hospital systems. Medical records were queried for the word "incidental," and matches were confirmed by manual review. Patients evaluated at Indiana University Health between January 1, 2014, and December 31, 2020, and those evaluated at University Hospitals between January 1, 2017, and December 31, 2020, were included. All patients were evaluated and treated by the two senior authors of this study and no others were included. Our search identified 625 patients. Sixteen percent (97 of 625) of patients were excluded because their lesions were not incidentally found, and 12% (78 of 625) were excluded because the incidental findings were not bone lesions. Another 4% (24 of 625) were excluded because they had received workup or treatment by an outside orthopaedic oncologist, and 2% (10 of 625) were excluded for missing information. A total of 416 patients were available for preliminary analysis. Among these patients, 33% (136 of 416) were indicated for surveillance. The primary indication for surveillance included lesions with a benign appearance on imaging and low clinical suspicion of malignancy or fracture. A total of 33% (45 of 136) of these patients had less than 12 months of follow-up and were excluded from further analysis. No minimum follow-up criteria were applied to patients not indicated for surveillance because this would artificially inflate our estimated rate of clinically important findings. A total of 371 patients were included in the final study group. Notes from all clinical encounters with orthopaedic and nonorthopaedic providers were screened for our endpoints (biopsy, treatment, or malignancy). Indications for biopsy included lesions with aggressive features, lesions with nonspecific imaging characteristics and a clinical picture concerning for malignancy, and lesion changes seen on imaging during the surveillance period. Indications for treatment included lesions with increased risk of fracture or deformity, certain malignancies, and pathologic fracture. Diagnoses were determined using biopsy results if available or the documented opinion of the consulting orthopaedic oncologist. Imaging reimbursements were obtained from the Medicare Physician Fee Schedule for 2022. Because imaging charges vary across institutions and reimbursements vary across payors, this method was chosen to enhance the comparability of our findings across multiple health systems and studies.

RESULTS

Seven percent (26 of 371) of incidental findings were determined to be clinically important, as previously defined. Five percent (20 of 371) of lesions underwent tissue biopsy, and 2% (eight of 371) received surgical intervention. Fewer than 2% (six of 371) of lesions were malignant. Serial imaging changed the treatment of 1% (two of 136) of the patients, corresponding to a rate of one in 47 person-years. Median reimbursements to work up the incidental findings analyzed was USD 219 (interquartile range USD 0 to 404), with a range of USD 0 to 890. Among patients indicated for surveillance, the median annual reimbursement was USD 78 (IQR USD 0 to 389), with a range of USD 0 to 2706.

CONCLUSION

The prevalence of clinically important findings among patients referred to orthopaedic oncology for incidentally found osseous lesions is modest. The likelihood of surveillance resulting in a change of management was low, but the median reimbursements associated with following these lesions was also low. We conclude that after appropriate risk stratification by orthopaedic oncology, incidental lesions are rarely clinically important, and judicious follow-up with serial imaging can be performed without incurring high costs.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Treatment trends of benign bone lesions in a suburban New York healthcare system

Introduction

The management of benign bone lesions is controversial as it is dependent on a multitude of factors such as age, anatomic location, comorbidities, lesion metabolic activity, surgeon preferences, and goals of care, among others. Thus far, many studies have attempted to report on these lesions; however, most are heterogeneous compilations of benign and malignant lesions with nearly all failing to report patient treatment and none of which have originated from a suburban area of the United States. The goal of this study was to establish a modern database dedicated solely to benign bone tumors to reflect current diagnosis and treatment trends in suburban New York.

Materials and Methods

This was a multicenter retrospective observational study with inclusion criteria limited to benign bone lesions of all ages. Malignant lesions were excluded. Patients were drawn from both primary care provider and surgeon records, with documentation of their associated management.

Results

A total of 689 patients met inclusion criteria. The overall operative rate for this cohort was 71.6%. In agreement with current literature, aneurysmal bone cysts, giant cell tumors, and osteochondromas underwent surgery more frequently than enchondromas; older patients underwent surgery less frequently; benign bone lesions were more commonly found in younger males, and the distal femur and proximal tibia were the most common locations for lesions (P < .05 for all findings).

Conclusion

This study demonstrates the management of a globally representative variety of benign bone lesions in a diverse suburban population of New York and should facilitate future research on how lesion type, location, management, and other factors relate to patient outcomes.

Inability to Ambulate in a Pediatric Patient Secondary to an Aneurysmal Bone Cyst With Associated Pathological Fracture

Bone pain in pediatric patients is exceedingly common, with etiologies ranging from benign lesions such as fibrous dysplasia and enchondromas to potentially devastating, life-threatening malignancies such as Ewing's sarcoma or osteosarcoma. Given the low yield of physical examination and routine laboratory workup, pediatric patients with bone pain or an inability to ambulate warrant further workup. The initial workup should consist of imaging with radiography. A large majority of patients will have a resolution of symptoms without intervention and will have normal imaging. When radiographic imaging has suspicious findings, expert consultation is warranted because differentiating between benign and malignant processes on imaging can be challenging. Here we present a case of a six-year-old male with progressive worsening leg pain who was found to have a rare aneurysmal bone cyst with an associated pathologic fracture requiring open reduction and internal fixation.

Spontaneous Resolution of an Osteochondroma

A 13-year-old girl presented with an apparent classic osteochondroma. Because she was skeletally immature, the decision was made to observe the lesion. She returned to the clinic at age 17 for unrelated reasons and was noted to no longer have the palpable mass. Magnetic resonance imaging confirmed resolution of the osteochondroma. The age range of this case fits with reported cases of childhood osteochondromas. The mechanism of resolution has been theorized to be incorporation of the lesion back into the bone during remodeling, fractures, or pseudoaneurysms. An initial period of observation is thus recommended with new patients.

Orthopaedic Manifestations of Neurofibromatosis Type I

Neurofibromatosis type 1 (NF1) is a congenital disease which is caused by mutations in the NF1 gene on chromosome 17, resulting in an altered function of the neurofibromin protein. Owing to the ubiquitous expression of this protein, this syndrome is associated with pathology in many organ systems of the body, especially the central and peripheral nervous, musculoskeletal, and integumentary systems. This review outlines the common sequelae related to a diagnosis of NF1 and the common treatment approach to each.

Prevalence of benign bone lesions of the lower extremity in the pediatric spinal disorders: a whole-body imaging study

There is a paucity of knowledge about benign bone lesions. The advances in imaging methods can screen bone lesions incidentally, and missing information can be provided. The aim of the study is to collect information about the prevalence and natural history of benign bone lesions with the use of whole-body biplanar slot-scanning imaging (EOS). EOS images acquired between 2015 and 2020 were retrospectively analyzed. Anatomical locations of lesions, number of lesions with polyostotic involvement and radiographic features of each were recorded. Fibrous lesions were further categorized according to the transition stages. The natural course was noted as remained in the same stage, progressed and disappeared during follow-up. A total of 1944 EOS images of 1378 (936 women and 442 men) patients were analyzed. The mean age was 12.3 (5-18) years. Bone lesions of the lower extremities were found in 278 scans (14.3%) of 196 (139 women and 57 men) patients (14.2%). Monostotic lesions were observed in 172 patients, and 24 had polyostotic lesions. The prevalence of lesions was 10.5%, 1.8%, 1.7%, 1.7% and 1.4‰ for fibrous cortical defect (FCD), nonossifying fibroma (NOF), osteochondroma, bone island and simple bone cyst, respectively. Among 145 FCDs, 55.2% of the lesions were stage A, 27.6% were stage B, 9.6% were stage C and 7.5% were stage D. EOS images acquired predominantly for spinal pathologies revealed a prevalence of 14% of benign bone tumors in the lower extremities. With the developments in imaging methods, the probability of encountering incidental lesion increases, and information about bone pathologies can be gathered.

Minor Shoulder Injury Reveals Spontaneous Regression of Proximal Humerus Osteochondroma

Osteochondromas are the most common benign bone tumor; nonetheless, the natural history is poorly understood as a result of the low threshold for resection and the fact that many of these lesions are asymptomatic and therefore never diagnosed. We present a case of a 17-year-old patient whose routine shoulder X-ray evaluation, due to a minor shoulder injury, revealed spontaneous regression of a previously documented left proximal humerus osteochondroma at six years follow-up. The likelihood of spontaneous regression should be better understood by orthopedic surgeons and taken into account in the decision process of whether to remove osteochondromas surgically or wait.