Pitfalls in the diagnosis of common benign bone tumours in children

Conventional Radiography Assessment of the Pediatric Knee: Pearls and Pitfalls

Knee pain is one of the most common indications for radiography in the evaluation of musculoskeletal disorders in children and adolescents. According to international guidelines, knee radiographs should be obtained when there is the suspicion of an effusion, limited motion, pain to palpation, inability to bear weight, mechanical symptoms (such as "locking"), and persistent knee pain after therapy. When indicated, radiographs can provide crucial information for the clinical decision-making process. Because of the developmental changes occurring in the knee during growth, the assessment of knee radiographs can be challenging in children and adolescents. Radiologists unfamiliar with the appearance of the knee on radiographs during skeletal maturation risk overcalling or overlooking bone lesions. Image acquisition techniques and parameters should be adapted to children. This article describes the most common challenges in distinguishing pathology from the normal appearance of knee radiographs in the pediatric population, offering some pearls and pitfalls that can be useful in clinical practice.

Imaging Aspects of Enchondromas in Pediatric Patients

Enchondromas are benign tumors located primarily in long bones, some of which can be accidentally discovered during imaging exams conducted for other pathologies. These benign cartilaginous tumors are hard to differentiate from low grade chondrosarcomas, which require periodic follow ups. The purpose of this study was to identify the incidence of enchondromas in pediatric patients, to determine medical imaging criteria (Computed Tomography-CT and Magnetic Resonance Imaging-MRI) in order to differentiate enchondromas from other atypical cartilaginous tumors, and to identify a potential correlation between imaging aspects and clinical signs. The aim of this study was to review imaging findings of enchondromas in children.

Edema-like marrow signal intensity (ELMSI) associated with nonossifying fibroma (NOF) on MRI: an uncommon finding in a common bone lesion

OBJECTIVE

To investigate the association between nonossifying fibroma (NOF) and perilesional edema-like marrow signal intensity (ELMSI) on MRI and discuss the clinical and diagnostic implications of this finding.

MATERIALS AND METHODS

A retrospective search for "nonossifying fibroma" and "NOF" on knee MRI reports of patients up to 20 years of age over a 5-year period was performed. A total of 77 patients (34 males, 43 females, ages 11-20) were identified, and each MRI was reviewed to evaluate for ELMSI associated with the NOF. Statistical analysis was performed to determine if there was a correlation with the presence of perilesional ELMSI and age, gender, lesion size, or signal characteristics.

RESULTS

Twelve patients out of 77 (16%) had ELMSI associated with a NOF. Excluding patients who had additional findings of pathologic fracture (n = 2), a known potential complication of NOFs, and edema related to an adjacent osteoid osteoma (n = 1), a total of 9 patients (12%) had otherwise unexplained perilesional ELMSI. There was no statistically significant difference between patients with vs. without perilesional ELMSI with respect to age (p = 0.08), gender (p = 0.28), lesion size (p = 0.52), or appearance on fluid-sensitive sequences (p = 0.81).

CONCLUSION

ELMSI can be seen about NOFs encountered around the knee joint on MRI, which may represent active healing and/or involutional change of this "do not touch" lesion in cases where no other explanation is identified.

"Do-not-touch" lesions of bone revisited

Incidental bone lesions are encountered frequently in day-to-day practice. Many of these lesions are indeterminate requiring referral to specialist centres for further characterisation with or without biopsy; however, as biopsy has its own drawbacks, not all lesions can be subjected to biopsy. The primary role of a radiologist in these situations is to characterise these lesions based on their imaging appearances into aggressive lesions requiring biopsy and non-aggressive lesions that do not require a biopsy. The term "do-not-touch lesion" is used to describe a lesion with typical radiographic appearances that can be characterised based on radiographic appearances alone without needing a biopsy. With recent advances in imaging, many incidental lesions can be characterised into do-not-touch lesions based on their imaging appearances alone using a single imaging technique or using a combination of imaging techniques and, less frequently, with the additional help of serological investigations, without the need for biopsy. Hence, the definition of do-not-touch lesions of bone needs a revisit. In this article, we attempt to redefine do-not-touch lesions of bone and propose an imaging-based classification for characterisation of these lesions.

Challenges in management of benign bone tumours complicated by pathological fracture in paediatric population

BACKGROUND

Optimum treatment of pathological fractures following benign bone tumours in paediatric population is controversial. The usual difficulties encountered while dealing such cases is to establish a correct pre-operative diagnosis and to choose between conservative vs operative management. The aim of the work is to highlight the difficult aspects of diagnosis and management of pathological fractures following benign bone tumours in paediatric population.

METHODS

All paediatric patients (<18 years) with pathological fractures following benign bone tumours were included. Pathological fractures due to infection, metabolic bone diseases and malignant bone tumours were excluded. Initial pre-operative diagnosis was based on clinico-radiological characteristics of the tumour and FNAC/needle biopsy, while final diagnosis was confirmed with post-operative histology. Primary outcome measure was determination of any disparity between pre-operative diagnosis and final post-operative histological diagnosis and the need of a separate open biopsy procedure for establishing the exact nature of lesion. Secondary outcome measures were determination of complications following surgery, functional grade and any recurrence at latest follow-up at 3 years.

RESULTS

Out of 13 patients enrolled for the study, twelve patients met the inclusion criteria. Female to male quotient was 3:1, with average age of 12.17 years. We were able to make correct pre-operative diagnosis in 10 patients (83.3%) with systematic clinico-radiological analysis and carefully performed FNAC/needle biopsy. Disparity between pre-operative and final post-operative diagnosis was seen in two patients. In one of these two patients, initial pre-operative diagnosis was fibrous dysplasia, which turned out to be ossifying fibroma on final post-operative biopsy. While the other patient required an open biopsy to establish the nature of underlying pathology, as the pre-op histological evaluation revealed equivocal nature of bone lesion. Secondary outcome measures showed superficial infection in one, coxa vara in one, limb length discrepancy in 2 and fibular graft donor site morbidity in two. None of the patient had developed recurrence. All patients had complete healing of the fracture and lesion.

CONCLUSION

A thorough clinico-radiological analysis and carefully performed FNAC/needle biopsy can establish a correct pre-operative diagnosis in majority of patients with benign bone tumours complicated by pathological fracture. This approach will avoid preventable delay in the definitive treatment of such patients, and also preclude the need of a separate operation prior to definitive management. In sight of the findings of our study along with existing literature we propose for definitive treatment in straight-forward cases and pre-treatment biopsy in cases with inconclusive FNAC/needle biopsy results and lesions with suspicion of malignancy. Proper diagnostic evaluation and differentiation of benign pathological fractures from malignant counterparts followed by extended curettage or excision of lesion and biological reconstruction with or without osteosynthesis represents a feasible approach for managing such fractures.

Imaging of Non-ossifying Fibromas: A Case Series

Non-ossifying fibromas (NOFs) are common lesions most frequently found in the growing bones of children and adolescents. Although NOFs are benign, their presence as incidental findings often triggers further investigation as they are sometimes mistaken for more sinister bone lesions such as aneurysmal bone cysts. NOFs can also pose an increased risk of pathological fractures. However, there are currently no guidelines on the follow-up of NOFs. We present a case series of five patients from Addenbrooke’s Hospital with NOFs illustrating their morphological features on plain radiographs and highlighting specific characteristics to support clinicians in diagnosing and managing NOFs.

Ten Commandments for the Diagnosis of Bone Tumors

The diagnosis of tumors and tumorlike lesions of bone is a routine part of both general and specialist radiologic practices. The spectrum of disorders ranges from the small incidental lesion to the potentially life-limiting malignancies whether primary or secondary. In this review, authored by experts from several European orthopaedic oncology centers, we present a collection of pieces of advice in the form of 10 commandments. Adherence in daily practice to this guidance should help minimize adverse patient experiences and outcomes.

A probable primary malignant bone tumor in a pre-Columbian human humerus from Cerro Brujo, Bocas del Toro, Panamá

We present a rare case of primary bone cancer principally affecting the right humerus of a skeleton from the pre-Columbian site of Cerro Brujo (1265-1380 CE) in Bocas del Toro, on the Caribbean coast of Panamá, excavated in the early 1970s. The humerus contains a dense, calcified sclerotic mass with associated lytic lesions localized around the midshaft of the diaphysis. Evidence of systemic inflammation and anemia, likely caused by the cancer, are visible in the form of severe porotic hyperostosis of the cranial vault and bilateral periosteal reactions in the tibiae. Differential diagnosis and future probes of the tumor are discussed. A tooth from the individual yielded a radiocarbon date 150 years later than those of the domestic occupation at the site. Given that it was the only formal burial recovered from the site, and as the individual had such a visible, painful, and rare pathology, this likely constitutes a ritual burial.