Cranial computed tomography in the detection of dural, orbital, and skull involvement in metastatic neuroblastoma

Comparison of Absolute Dose Achievable Between Helical Tomotherapy and RapidArc in Total Dura Mater Irradiation for Child Cancer

Background and Purpose: In this study, the absolute dose achievable between helical tomotherapy (HT) plans and RapidArc (RA) plans for total dura mater irradiation (TDMI) was compared. Materials and methods: A planning study was conducted on nine children's case datasets with dura mater metastasis of neuroblastoma. The target included the entire calvarium and skull base and formed a closed volume with a certain thickness around the brain. HT and RA plans with four coplanar full arcs (RA4) with half-field technique were generated for the comparison of absolute dose achievable. In total, 30.6 Gy was prescribed as D_95% (ie, dose to 95% of PTV volume). Results: In the dosimetric comparison between the two modalities, HT provided more homogenous dose distribution than RA4 (mean HI_5−95%: 1.046 vs 1.088, P < .001). The V_107% and D_2Gy of PTV in HT versus RA4 were 3.06% versus 30.47% and 32.59 Gy versus 33.45 Gy, respectively. HT reduced the D_mean and V_5Gy of the brain, brainstem, and hippocampus by 25%–48% and 27%–56% compared with RA4, respectively. Conclusion: Both techniques could provide sufficient coverage for targets, but HT offered more homogenous dose to PTV and lower dose to the central region of the brain involving the brainstem and hippocampus. RA4 could be completed in a shorter time with lower MUs, but with relatively higher dose to the brain or hippocampus. In terms of dosimetry, HT may improve long-term cognitive decline in these young pediatric patients with TDMI.

Imaging Spectrum of Calvarial Abnormalities

Calvarial abnormalities are usually discovered incidentally on radiologic studies or less commonly manifest with symptoms. This narrative review describes the imaging spectrum of the abnormal calvaria. The extent, multiplicity, and other imaging features of calvarial abnormalities can be combined with the clinical information to establish a final diagnosis or at least narrow the differential considerations. Prior trauma (congenital depression, leptomeningeal cysts, posttraumatic osteolysis), surgical intervention (flap osteonecrosis and burr holes), infection, and inflammatory processes (sarcoidosis) can result in focal bone loss, which may also be seen with idiopathic disorders without (bilateral parietal thinning and Gorham disease) or with (Parry-Romberg syndrome) atrophy of the overlying soft tissues. Anatomic variants (arachnoid granulations, venous lakes, parietal foramina) and certain congenital lesions (epidermoid and dermoid cysts, atretic encephalocele, sinus pericranii, and aplasia cutis congenita) manifest as solitary lytic lesions. Other congenital entities (lacunar skull and dysplasia) display a diffuse pattern of skull involvement. Several benign and malignant primary bone tumors involve the calvaria and manifest as lytic, sclerotic, mixed lytic and sclerotic, or thinning lesions, whereas multifocal disease is mainly due to hematologic or secondary malignancies. Metabolic disorders such as rickets, hyperparathyroidism, renal osteodystrophy, acromegaly, and Paget disease involve the calvaria in a more diffuse pattern. Online supplemental material is available for this article. ^©RSNA, 2021.

A systematic approach in the diagnosis of paediatric skull lesions: what radiologists need to know

Paediatric skull lesions are commonly identified on imaging. They can be challenging to image, given their location and size, and often require several imaging modalities to narrow down the differential diagnosis. Accurate diagnosis of these lesions is paramount because the clinical therapy can vary tremendously. In this review, we provide a simple and systematic approach to clinical-radiological features of primary skull lesions. We highlight the imaging characteristics and differentiate pathologies based on imaging appearances. We also accentuate the role of cross-sectional imaging in lesion identification and management implications.

Melanotic neuroectodermal tumour of infancy: A case report and differential diagnosis

Melanotic neuroectodermal tumour of infancy is an uncommon pigmented neoplasm of neural crest origin. It was first described in 1918 by Krompecher, known as congenital melanocarcinoma at that time. Although it is generally agreed upon that it is a benign entity, it is locally aggressive and has a significant recurrent risk, reported to be between 10-15%. There have also been prior reports of malignant behaviour in these tumours, although extremely rare. The majority of cases of this tumour (about 70%) arise from the maxilla and its occurrence in the cranial vault represents approximately 15.6% of cases. We describe a rare case of melanotic neuroectodermal tumour of infancy, with simultaneous involvement of the cranial vault and petrous temporal bone, in a four-month-old child, complicated by post-surgical pseudo-meningocele. This case illustrates the diagnostic dilemma in differentiating reactive osseous sclerosis from direct tumour infiltration, both of which can occur in the context of melanotic neuroectodermal tumour of infancy. The discussion places emphasis on differential diagnoses and useful radiological features to assist in clinching the diagnosis of melanotic neuroectodermal tumour of infancy.

Imaging of metastatic CNS neuroblastoma

OBJECTIVE

Although neuroblastoma is a common childhood malignancy, which frequently metastasizes, involvement of the CNS is rarely reported in the literature. However, over the past several years, we have encountered an increasing number of cases of metastatic neuroblastoma to the CNS. This metastatic potential and changing metastatic pattern may, in part, be due to advances in medical treatment, leading to prolonged survival. This article will review the common and uncommon manifestations of metastatic neuroblastoma with an emphasis on the skull, dura, brain, ventricles, and leptomeninges.

CONCLUSION

Neuroblastoma has diverse manifestations including masquerading as primary neurologic disease. This disease must be considered in a child with any unexplained neurologic disorder. Realizing that neuroblastoma may represent the cause of neurologic disease in a child will lead to earlier diagnosis.

Presentation and diagnosis of unilateral maxillary swelling in children

Facial asymmetry secondary to pathologic processes involving the maxillary sinus and its surrounding structures presents a challenge for the clinician. An organized approach to evaluate these patients is essential in order to differentiate inflammatory sinus pathology from disease processes primarily involving the surrounding maxilla, parotid gland, orbital contents, and dental structures. In addition to a thorough history and physical examination, appropriate imaging studies must be obtained to localize the pathologic processes and develop a meaningful differential diagnosis. Once this is accomplished, specific treatment modalities can be developed. Representative cases will be presented to illustrate this organized approach to unilateral maxillary swelling, including soft tissue and osseous masses, fibro-osseous lesions, osseous cysts and inflammatory lesions.