Non-odontogenic tumors of the facial bones in children and adolescents: role of multiparametric imaging

Multimodal imaging for the differential diagnosis and efficacy evaluation of intraocular retinoblastoma in children with selective ophthalmic artery infusion

Background

Retinoblastoma (RB) is the most common malignant tumor in children under the age of 3 years and is associated with a high disability and mortality rate. The aim of this study was, first, to evaluate the clinical efficacy of multimodal imaging in differentially diagnosing RB in children and in predicting the efficacy of selective ophthalmic artery infusion (SOAI) and, second, to identify the factors associated with this efficacy.

Methods

This study retrospectively collected the data from 256 children with unilateral RB and intraocular involvement, including multimodal imaging magnetic resonance imaging (MRI), computed tomography (CT), and clinical characteristics. Among the cases, 33 with both CT and MRI data available were used to evaluate the diagnostic accuracy in distinguishing RB, with histopathological results serving as the gold standard. Additionally, a retrospective analysis was conducted on the MRI and clinical characteristics of 256 cases of unilateral RB with intraocular involvement before SOAI treatment. The predictive ability of imaging features and clinical characteristics for the treatment efficacy of children was analyzed, and the differences in globe salvage rates and visual preservation based on different tumor stages were evaluated.

Results

The diagnostic accuracy of CT imaging for RB was 96.96% while that of MRI was 84.84%, with both showing high consistency with the histopathological results. CT images demonstrated a posterior intraocular mass with a high-density appearance, with spots, patches, or clustered calcifications visible within the tumor. The CT values were mostly above 100 Hounsfield units (HU), and enhanced scanning showed varying degrees of enhancement in noncalcified masses. MRI showed low or moderate signal intensity on T1-weighted images and moderate-to-high signal intensity on T2-weighted images, with significant enhancement after contrast administration. Tumors with more calcifications showed long T1 and short T2 signals. Patients with better prognosis had a higher delta signal increase (ΔSI), a greater distance from the optic disc, smaller tumor diameter, absence of implantation nodules or smaller implantation range, endogenous growth pattern, smaller extent of retinal detachment, absence of clinical high-risk factors, no vitreous hemorrhage, no globe shrinkage, and smaller calcification volume. The distance between the tumor and optic disc, clinical high-risk factors, and tumor growth pattern were found to be independent factors associated with prognosis. The rate of successful globe salvage and visual acuity decreased with increasing tumor stage.

Conclusions

CT and MRI are highly valuable for the comprehensive assessment of tumors in pediatric RB. MRI alone can complete a comprehensive assessment of patients with RB and thus allow for the reduction radiation dose in children. Calcification of the tumor is crucial for diagnosis, and imaging findings can serve to inform patient prognosis and treatment planning. The distance between the tumor and optic disc, clinical high-risk factors, and tumor growth pattern are closely related to the prognosis of children.

Nonsyndromic Craniofacial Disorders

We describe the investigation and management of select pediatric craniofacial disorders their recent advances. Positional plagiocephaly: The incidence of positional plagiocephaly has increased since the institution of the "safe to sleep" campaign to reduce sudden infant death syndrome. Positional plagiocephaly may be associated with underlying developmental delay. Nonsyndromic craniosynostosis: Treatment of nonsyndromic craniosynostosis depends on the age of the patient and the suture involved. Pediatric skull lesions: Management of skull lesions depends on histologic diagnosis. Some benign skull lesions are managed conservatively, whereas erosive and malignant lesions may require surgical excision, radiotherapy, chemotherapy, or multimodality treatment.

EWS/FLI1 Characterization, Activation, Repression, Target Genes and Therapeutic Opportunities in Ewing Sarcoma

Despite their clonal origins, tumors eventually develop into complex communities made up of phenotypically different cell subpopulations, according to mounting evidence. Tumor cell-intrinsic programming and signals from geographically and temporally changing microenvironments both contribute to this variability. Furthermore, the mutational load is typically lacking in childhood malignancies of adult cancers, and they still exhibit high cellular heterogeneity levels largely mediated by epigenetic mechanisms. Ewing sarcomas represent highly aggressive malignancies affecting both bone and soft tissue, primarily afflicting adolescents. Unfortunately, the outlook for patients facing relapsed or metastatic disease is grim. These tumors are primarily fueled by a distinctive fusion event involving an FET protein and an ETS family transcription factor, with the most prevalent fusion being EWS/FLI1. Despite originating from a common driver mutation, Ewing sarcoma cells display significant variations in transcriptional activity, both within and among tumors. Recent research has pinpointed distinct fusion protein activities as a principal source of this heterogeneity, resulting in markedly diverse cellular phenotypes. In this review, we aim to characterize the role of the EWS/FLI fusion protein in Ewing sarcoma by exploring its general mechanism of activation and elucidating its implications for tumor heterogeneity. Additionally, we delve into potential therapeutic opportunities to target this aberrant fusion protein in the context of Ewing sarcoma treatment.

Mandibular Metastasis in Neuroblastoma in a 3 Year-Old Child: A Case Report

Neuroblastomas commonly metastasize to the cranium and orbit, although other facial bones were less implicated. In this report we present a 3 years old child with metastatic neuroblastoma to the mandible that presented with swollen right jaw. The first assessment of the head with computed tomography revealed soft tissue mass with permeative lytic changes of the osseous structures centered on the right mandible, as well as osteo-meningitis metastases. These masses were proven to be metastatic lesions from intra-abdominal neuroblastoma of the right adrenal gland. Over the previous several years, only 29 cases of neuroblastoma metastasis to the mandible have been reported in the literature.

Benign Pediatric Jawbone Lesions: A 10-Year Clinical and Radiological Pilot Study

This study aimed at presenting a retrospective longitudinal analysis of the pediatric jaw lesions treated at the Oral and Maxillofacial Surgery Clinic in Cluj-Napoca, Romania, over a timeframe of ten years (2012 to 2022). The clinical and radiological characteristics of the jawbone lesions, the treatment outcome, and the recurrence incidence were described. All consecutive patients aged below 18 years, with histologically diagnosed odontogenic tumors (OTs), nonodontogenic tumors (non-OTs), or odontogenic cysts (OCs) were included. Age, dentition type, clinical symptoms, preoperative and postoperative radiological tests, histological diagnosis, treatment, and follow-up information one year following the diagnoses were all examined. Eighty-two cases were included. The ratio of men to women was 1.15:1, with the mandible predominating by 64.4%. Inflammatory radicular cysts predominated in 31.7% of cases. A total of 42.68% of the patients were asymptomatic. Enucleation was the most frequent surgical technique (45.1%), followed by cystectomies (28%) and marsupialization (14.6%). The overall recurrence rate was 7.3%; the most recurrent histopathological lesion was the odontogenic keratocyst. This study sheds new light on the clinical and radiological characteristics, treatment outcomes, and recurrence rate of juvenile jawbone lesions in children and adolescents. The diagnosis and treatment of jawbone lesions in children and adolescents can be enhanced with the use of epidemiological, clinical, and imagistic information.

Diagnostic Challenge in Rapidly Growing Langerhans Cell Histiocytosis with Aneurysmal Bone Cyst in the Maxilla: A Case Report

Langerhans cell histiocytosis (LCH) is a rare neoplastic disorder characterized by the clonal proliferation of CD1a +/CD 207 + dendritic cells, whose features are similar to those of epidermal Langerhans cells. LCH is more common in children than in adults. Localized osteolytic lesions in the craniofacial bones are the most common manifestations of LCH. However, LCH can also present as a multifocal and multisystem disease with poor prognosis. Locally aggressive LCH needs to be differentiated from various diseases such as osteomyelitis, malignant bone tumors, and soft tissue sarcomas. However, it is difficult to diagnose, since the imaging findings are nonspecific. We report a case of a highly aggressive LCH in the maxilla accompanied by a fluid-fluid level.

Benign Bone-Forming Tumors

Benign bone-forming tumors comprise osteomas, osteoid osteomas, and osteoblastomas. Osteomas affect a wide age range and are usually discovered incidentally. They occur predominantly in the craniofacial skeleton and are classically composed of compact bone. Osteoid osteomas and osteoblastomas are painful lesions occurring in young patients. They are morphologically similar and characterized by FOS gene rearrangement and c-FOS expression at a protein level. Osteoid osteomas are usually smaller than 2 cm in maximum dimension with limited growth potential; osteoblastomas are larger than 2 cm and may be locally aggressive. Histologically both are composed of anastomosing trabeculae of woven bone.

Pediatric skeletal diffusion-weighted magnetic resonance imaging, part 2: current and emerging applications

Diffusion-weighted imaging (DWI) complements the more established T1, fluid-sensitive and gadolinium-enhanced magnetic resonance pulse sequences used to assess several pediatric skeletal pathologies. There is optimism that the technique might not just be complementary but could serve as an alternative to gadolinium and radiopharmaceuticals for several indications. As a non-contrast, free-breathing and noninvasive technique, DWI is especially valuable in children and is readily incorporated into existing MRI protocols. The indications for skeletal DWI in children include distinguishing between benign and malignant skeletal processes, initial assessment and treatment response assessment for osseous sarcomas, and assessment of inflammatory arthropathies and femoral head ischemia, among others. A notable challenge of diffusion MRI is the dynamic nature of the growing pediatric skeleton. It is important to consider the child's age when placing DWI findings in context with potential marrow pathology. This review article summarizes the current and evolving applications of DWI for assessing the pediatric skeleton, rounding off the discussion with evolving directions for further research in this realm.

A Pattern-based Imaging Approach to Pediatric Jaw Lesions

Jaw lesions in the pediatric population, although infrequently encountered in clinical practice, can cause functional impairment and cosmetic disfiguring. It is further complicated by the difficulty in diagnosis due to complex anatomy and facial developmental process during infancy and childhood. Intraosseous pediatric jaw lesions may vary from odontogenic to nonodontogenic types with nonspecific clinical features in most cases. They deserve careful attention by a systematic approach to provide a relevant diagnosis or differential diagnosis for timely management. Imaging plays a major role in diagnosis with orthopantomograph being the foremost investigation, followed by cross-sectional imaging, essentially computed tomography as a problem-solving tool. This article highlights the imaging spectrum of various jaw lesions in the pediatric population with a pattern-based approach for radiological diagnosis.

Mandibular metastases in neuroblastoma: Outcomes and dental sequelae

BACKGROUND

Although metastatic involvement of bony sites including cranial bones is common in neuroblastoma (NB), mandibular metastases (MM) are uncommon, and specific outcomes have not been reported upon in the modern therapeutic era.

METHODS

In this retrospective study, medical records on patients with MM from NB were reviewed. Statistical analysis was performed using the Kaplan-Meier method.

RESULTS

Of 29 patients, nine (31%) had MM at diagnosis, whereas in 20 (69%) MM were first detected at NB relapse at a median time of 26 (6-89) months from diagnosis. Median maximal diameter of lesions was 3 (range 0.8-4.9) cm. MM were unilateral in 83% of patients, with ascending ramus (55%) and mandibular body (38%) being the two most common sites. All patients received systemic chemotherapy, and 26 (93%) patients received radiotherapy to MM. At a median follow-up of 37.3 (24.2-219.5) months, eight of nine patients with MM at diagnosis did not experience mandibular progressive disease. Eighteen of 20 patients with MM at relapse received therapeutic radiotherapy; objective responses were noted in 78%. Seventy-two percent (5/18) had not experienced relapse within the radiation field at a median of 12 (2-276) months postradiotherapy. Dental findings at follow-up after completion of NB therapy included hypodontia, hypocalcification of enamel, and trismus. Median 3-year overall survival in patients with relapsed MM was 51 ± 12% months from relapse.

CONCLUSION

MM when detected at diagnosis is associated with a prognosis similar to that for other skeletal metastases of NB. Radiotherapy is effective for control of MM detected both at diagnosis and relapse. Significant dental abnormalities posttherapy warrant regular dental evaluations and appropriate intervention.

Bone-related disorders of the jaw: A clinico-radiological diagnostic algorithm

Bone-related disorders of the jaw (BRDJ) include a spectrum of non-neoplastic and neoplastic lesions of the maxillofacial region that have been recently classified into fibro-osseous lesions, giant cell lesions and osseous tumours. The histopathological features of BRDJ can be similar and overlie each other. Imaging is important in order to reach a specific diagnosis. However, the appearance of BRDJ on imaging is non-specific in some cases. Computed tomography (CT) and magnetic resonance imaging (MRI) are used for accurate localisation, characterisation of the tumour matrix, delineation of the lesion extension and establishment of the relation of BRDJ to the surrounding structures. Imaging is usually done to detect the relationship with the adjacent surrounding vital structures and to diagnose aggressive forms, malignant transformation and associated syndromes. The correlation of the demographic findings, the location and the clinical presentations with the imaging features are important for the diagnosis of BRDJ. The proposed clinico-radiological diagnostic algorithm with CT and MRI helps a specific diagnosis to be reached in some cases.

Pediatric Panoramic Radiography: Techniques, Artifacts, and Interpretation

Panoramic radiography, particularly in the pediatric population, is rarely addressed in the radiology literature. The authors provide an in-depth discussion of how these images are acquired, what artifacts can be visualized, and how to mitigate these artifacts. Dental anatomy, as well as relevant osseous and soft-tissue anatomy visible on a panoramic image, are reviewed. The appearance of the normal pediatric panoramic radiograph, with an emphasis on the dental follicle, is discussed, as well as how to differentiate this normal structure from underlying pathologic conditions. The most commonly encountered pathologic conditions of carious disease and trauma are emphasized. A systematic approach to diagnosing mass lesions and their appropriate work-up, including multimodality imaging examples of relevant pathologic conditions, is also provided. Finally, congenital anomalies, including some of the more commonly encountered dysplasias, are reviewed. The authors provide a concise review of the relevant information needed to confidently interpret a pediatric panoramic radiograph. The online slide presentation from the RSNA Annual Meeting is available for this article. ^©RSNA, 2021.

Radiological diagnostic dilemma in a child with small aggressive facial mass, time to increase the differentials: an inflammatory myofibroblastic tumour

A 5-year-old girl with left facial swelling in the medial maxillary region close to the nasal ala was brought by her parents to our head and neck clinic. They have visited other doctors for similar presentation in the last 6 months, which started as redness and swelling, with occasional epiphora. The redness resolved after medical treatment, with slight regression of swelling, although it did not disappear. CT and MRI showed a locally aggressive, small enhancing soft tissue mass involving the left anteromedial maxillary wall, the nasal bone and the orbital floor. The mass involved the bony course of the nasolacrimal duct, which was the aetiology of the epiphora. The head and neck team performed an incisional biopsy through a sublabial approach. Concurrently, a nasolacrimal duct stent was inserted by an ophthalmologist. Histopathology was consistent with inflammatory myofibroblastic tumour with positive stains for CD68, CD163 and anaplastic lymphoma kinase-1. The tumour was excised and presently the patient is on periodic follow-up with head and neck and ophthalmology clinics.

Incidental Findings in TMJ Imaging

For years, the conventional imaging modalities are generally used in dental practice routine. They provide precious information about dentomaxillofacial region; they also have some limitations such as superimpositions, magnifications, distortions, and low-image quality. Because of these limitations, some pathologies, calcifications, and anatomical variations may be missed. Any findings on a radiographic image which are not related to the research areas of interest could be a description of “incidental findings.” Calcifications are one of these incidental findings. They are asymptomatic and also common in TMJ images. Although most of the calcifications require no treatment, correct identification will reduce further diagnostic assessments. Incidental findings on TMJ images were rare, while examining images for temporomandibular disorders and associated issues, it is important not only to examine the TMJ structures but also to look at the nearby anatomical features to check for evidence of incidental findings pathologies that may have mimicked signs and symptoms of TMJ disorders.

Masses of developmental and genetic origin affecting the paediatric craniofacial skeleton

Although rare, masses and mass-like lesions of developmental and genetic origin may affect the paediatric craniofacial skeleton. They represent a major challenge in clinical practice because they can lead to functional impairment, facial deformation and disfigurement. The most common lesions include fibrous dysplasia, dermoid cysts, vascular malformations and plexiform neurofibromas. Less common lesions include torus mandibularis and torus palatinus, cherubism, nevoid basal cell carcinoma syndrome, meningoencephalocele and nasal sinus tract. This article provides a comprehensive approach for the evaluation of children with masses or mass-like lesions of developmental and genetic origin affecting the craniofacial skeleton. Typical findings are illustrated and the respective roles of computed tomography (CT), cone beam CT (CBCT), magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) sequences and ultrasonography (US) are discussed for the pre-therapeutic assessment, complex treatment planning and post-treatment surveillance. Key imaging findings and characteristic clinical manifestations are reviewed. Pitfalls of image interpretation are addressed and how to avoid them. TEACHING POINTS: • Masses of developmental and genetic origin may severely impair the craniofacial skeleton. • Although rare, these lesions have characteristic imaging features. • CT, MRI and ultrasonography play a key role in their work-up. • Recognition of pivotal imaging pearls and diagnostic pitfalls avoids interpretation errors.

CT and MR imaging characteristics of histological subtypes of head and neck ossifying fibroma

OBJECTIVES

The current study aimed to assess CT and MRI characteristics of histological subtypes of head and neck ossifying fibroma (OF).

METHODS

12 patients with histopathologically-proven head and neck OF were included in this study. Lesions were pathologically classified into three histological subtypes: eight cement-OFs (COFs), three juvenile psammomatoid OFs (JPOFs), and one juvenile trabecular OF (JTOF). All patients underwent CT examination, while seven also underwent MRI. Imaging characteristics were retrospectively assessed.

RESULTS

On CT images, the lesion margins were well-defined in nine patients (75%) (seven COFs and two JPOFs), partially ill-defined in two (17%) (one COF and one JTOF), and ill-defined in one (8%) (one JPOF). The continuity of the eroded overlying bone cortex was maintained in nine patients (75%) (seven COFs and two JPOFs) but disrupted in three (25%) (one COF, one JPOF, one JTOF). With respect to lesion density, homogeneous ground-glass opacity was observed in five patients (42%) (five COFs), target-like appearance in three (25%) (two COFs, one JPOF), and mixture of hyper- and hypodense areas were observed in four (33%) (one COF, two JPOFs, one JTOF). MR signal intensity was homogeneous in two patients (29%) (two COFs) and heterogeneous in five (71%) (two COFs, two JPOFs, one JTOF).

CONCLUSIONS

COFs tended to exhibit well-defined margins and preserved continuity of the overlying bone cortex. COFs were usually homogeneous, whereas JPOFs and JTOF were always heterogeneous. Target-like appearance was one of the characteristics of OFs, but it was observed in both COF and JPOF.

Craniofacial Manifestations of Systemic Disorders: CT and MR Imaging Findings and Imaging Approach

Many systemic diseases or conditions can affect the maxillofacial bones; however, they are often overlooked or incidentally found at routine brain or head and neck imaging performed for other reasons. Early identification of some conditions may significantly affect patient care and alter outcomes. Early recognition of nonneoplastic hematologic disorders, such as thalassemia and sickle cell disease, may help initiate earlier treatment and prevent serious complications. The management of neoplastic diseases such as lymphoma, leukemia, or Langerhans cell histiocytosis may be different if diagnosed early, and metastases to the maxillofacial bones may be the first manifestation of an otherwise occult neoplasm. Endocrinologic and metabolic disorders also may manifest with maxillofacial conditions. Earlier recognition of osteoporosis may alter treatment and prevent complications such as insufficiency fractures, and identification of acromegaly may lead to surgical treatment if there is an underlying growth hormone-producing adenoma. Bone dysplasias sometimes are associated with skull base foraminal narrowing and subsequent involvement of the cranial nerves. Inflammatory processes such as rheumatoid arthritis and sarcoidosis may affect the maxillofacial bones, skull base, and temporomandibular joints. Radiologists should be familiar with the maxillofacial computed tomographic and magnetic resonance imaging findings of common systemic disorders because these may be the first manifestations of an otherwise unrevealed systemic process with potential for serious complications. Online supplemental material is available for this article. ^©RSNA, 2018.

[Postoperative and posttherapeutic changes after primary bone tumors : What's important for radiologists?]

Posttreatment imaging of primary bone tumours represents a diagnostic challenge for radiologists. Depending on the primary bone tumour common radiological procedures, such as radiography, computed tomography (CT), and magnetic resonance imaging (MRI), are employed. Radiography and CT are particularly useful in benign bone tumours and in matrix-forming bone tumours. MRI comes into consideration with malignant tumour recurrence and tumoral soft tissue infiltration. Bone scintigraphy is of superior importance if a primarily multifocal manifestation of bone tumour or metastasizing tumour disease is suspected. Molecular imaging (FDG-PET and hybrid imaging, using CT) are gaining increasing importance in light of monitoring neoadjuvant chemotherapy and detecting recurrent tumour appearance. The current literature shows sensitivity and specificity values for recurrent detection of up to 92% and 93%. Diagnostic accuracy is as high as 95%, thus, exceeding accuracy values for CT (67%) and MRI (86%) by far. Likewise, this is also applicable for the assessment of the neoadjuvant chemotherapy. Moreover, PET-based modalities are able to establish prognostic statements using SUV-threshold values at baseline (especially for Ewing sarcomas). Advanced imaging techniques have made a great diagnostic step forward and have proven to be relevant and reproducible with respect to both relapse detection and treatment assessment. Furthermore, it is not clear whether a higher detection rate of early tumour recurrence will inevitably lead to better outcome and survival.