In patients who undergo decompressive surgery for CM-I, intraoperative ultrasonography may be a useful tool to aid the surgeon in deciding whether to opt for bone removal only or bone removal plus duraplasty and tonsillar shrinkage.

The most common cystic malformations of the neck are the result of abnormal embryogenesis involving the thyroglossal duct (TGD), lymphatic primordia and the branchial apparatus. When the basic embryology of these structures is considered, a reasonable differential diagnosis-and in some cases a definitive diagnosis-can be achieved based on the location and the imaging characteristics of the cystic mass.

The association between sudden death and cervicomedullary compression in infants with achondroplasia has been well described. Prospective clinical and imaging evaluations have been recommended to identify those infants with achondroplasia who are at risk of dying suddenly from respiratory arrest secondary to unrecognized cervicomedullary compression. Since 1988, we have prospectively evaluated 11 infants (average age 13 weeks) with achondroplasia who were asymptomatic for cervicomedullary compression on initial clinical evaluation. Craniocervical magnetic resonance imaging (MRI) findings included narrowing of the foramen magnum, effacement of the subarachnoid spaces at the cervicomedullary junction, abnormal intrinsic cord signal intensity and mild to moderate ventriculomegaly. Two patients with severe cord compression underwent immediate decompression. Two patients developed opisthotonic posturing within 3 months of evaluation and underwent foramen magnum decompression, including suboccipital craniectomy and atlantal laminectomy. Surgery in all cases revealed forward extension of the squamous portion of the occipital bone, thickened posterior rim of the foramen magnum and a dense fibrotic epidural band. There were no complications from surgery. Seven patients did not require surgery and were followed closely. All 11 patients remain asymptomatic at follow-up (mean 4.6 years; range 16 months to 7.3 years), and no patient has required a diversionary shunt procedure. The results of this prospective study confirm that early clinical and MRI evaluations are necessary to determine whether infants with achondroplasia have cervicomedullary compression. With early recognition, an immediate decompression can be performed safely to avoid serious complications associated with cervicomedullary compression, including sudden death.

A wide range of masses develop in the nose, nasal cavity, and nasopharynx in children. These lesions may arise from the nasal ala or other structures of the nose, including the mucosa covering any surface of the nasal cavity, the cartilaginous or osseous portion of the nasal septum, the nasal turbinates, and the nasal bones. Lesions may also arise from the nasopharynx or adjacent structures and involve the nose by way of direct extension. The causes of nasal masses in children include congenital and developmental disorders such as congenital nasolacrimal duct mucocele, dermoid cyst, cephalocele, and nasal neuroglial heterotopia; inflammatory and infectious processes such as mucocele, polyp, and pyogenic granuloma; benign neoplasms such as infantile hemangioma and juvenile nasopharyngeal angiofibroma; malignant lesions such as rhabdomyosarcoma and nasopharyngeal carcinoma; and masses related to prior trauma such as septal hematoma. Although direct visualization, without imaging, is frequently sufficient to diagnose pediatric nasal conditions, in many cases imaging has a key role in the treatment of the affected child. Some of these lesions have characteristic computed tomography and/or magnetic resonance imaging findings, some of them are diagnosed on the basis of the location and imaging findings combined, and others demonstrate nonspecific imaging findings. However, imaging is important for better defining the total extent of the lesion and guiding the clinician in determining whether medical and/or surgical intervention is required. In this article, the authors review the imaging findings of the most common causes-and many of the not-so-common causes-of nasal masses encountered in the pediatric population. RSNA, 2017.