On cross-sectional imaging, it appears as a lobulated mass with intense uniform enhancement, which usually demonstrates intralesional flow voids on MRI (Fig. 14-2, A). Proliferation may be biphasic. Careful assessment of upper airway status is important because the deep portions of a cervical hemangioma may enlarge sufficiently at this stage to impinge on the airway and cause obstruction. During the final involution phase, which may continue for up to 12 years, the rate of regression is variable. Involution is never complete, although the residual lesion may not be grossly visible; in the neck, it leaves persistent fibrofatty tissue. Infantile hemangiomas are positive for the glucose transporter 1 (GLUT-1) marker at all stages of lesion development.

Figure 14-2 Infantile hemangiomas.
A, Parotid infantile hemangioma. A T2-weighted axial image with fat suppression shows a well-circumscribed lobular soft tissue mass in the left parotid with intrinsic flow voids and deep extension into the ipsilateral parapharyngeal space (arrow). The upper airways remain patent. B and C, Upper airways infantile hemangiomas. A T2-weighted axial image with fat suppression shows a small hyperintense hemangioma in the left vocal cord (black arrow), causing severe airway effacement (B). A sagittal reconstructed computed tomography image shows a small lobulated enhancing subglottic hemangioma (black arrow) (C). D, Multifocal infantile hemangiomas with intracranial lesions. A T2-weighted coronal image with fat suppression shows cervical (white arrow) and Meckel cave (black arrow) hemangiomas. (C, Courtesy Avrum N. Pollock, MD.)

Most infantile hemangiomas do not cause any morbidity or mortality but may create cosmetic inconvenience. Nonetheless, a hemangioma of the neck is considered an alarming lesion if it assumes a beard distribution (involvement of the lower face, anterior neck, and submandibular and parotid regions) because of an increased incidence of subglottic hemangioma, high risk of airway compromise, and known association with PHACES syndrome (Posterior fossa malformations, Hemangiomas, Arterial, Cardiac anomalies, Eye anomalies, Sternal cleft). The arteriopathy of PHACES syndrome commonly comprises a spectrum of congenital and progressive large arterial lesions ipsilateral to the cutaneous hemangioma. It entails careful searching (and monitoring) with imaging for potential vascular anomalies once a diagnosis of cervicofacial segmental hemangioma is established.

Upper airway hemangiomas (see Fig. 14-2, B and C) become symptomatic in the proliferative phase, causing biphasic stridor, respiratory distress, and potentially even life-threatening airway obstruction, which may require emergent intubation. These hemangiomas are often multifocal and occur above and below the vocal cords. Close monitoring with cross-sectional imaging may be indicated because laryngoscopy may not accurately depict the degree of invasion. MRI is preferred in the setting of intubation or tracheostomy.

In rare cases, cervicofacial infantile hemangioma may be associated with central nervous system hemangiomas in intracranial (see Fig. 14-2, D) or intraspinal locations. The reported cases of central nervous system hemangiomas indicate a specific pattern of distribution, with a predilection for the basal cisterns, ventricular system, and extradural spinal involvement.

In the past, infantile hemangiomas have been confused with other vascular neoplasms, particularly kaposiform hemangioendotheliomas (KHEs) and tufted angiomas, especially in the setting of consumptive coagulopathy, referred to as the Kasabach-Merrit phenomenon; it is now generally accepted that infantile hemangiomas are rarely, if ever, responsible for this phenomenon.

Congenital Hemangioma

Congenital hemangiomas are uncommon lesions that are fully developed at birth and do not go through the proliferative stage in postnatal life. These lesions may be diagnosed in utero, as early as at 12 weeks of gestational age. Two types of congenital hemangiomas are described: (1) rapidly involuting congenital hemangioma (RICH) and (2) noninvoluting lesions congenital hemangioma (NICH).

RICH has a predilection for scalp and neck locations. On prenatal imaging, it may appear as a large heterogeneous mass, emanating from the posterior neck (Fig. 14-3, A) with increased vascularity, best demonstrated on obstetric Doppler ultrasonography. Postnatal imaging features of RICH include large irregular flow voids and arterial aneurysms, direct arteriovenous shunts (seen on angiography), and calcifications. Their imaging appearance may occasionally resemble congenital infantile fibrosarcoma.

Figure 14-3 Congenital hemangiomas.
A, A fetal magnetic resonance imaging, sagittal half Fourier acquisition single shot turbo spin echo image shows a complex soft tissue mass in the posterior neck (black arrow) with internal hypointensity, indicative of blood products. B, A sagittal magnetic resonance imaging T2-weighted image of a 1-day-old newborn’s neck shows a very large heterogeneous mass with internal flow voids in the posterior neck. Enlargement of ipsilateral carotid artery (white arrow) and cardiomegaly indicate high-output congestive heart failure.

RICH may have a dramatic presentation at birth with high-output congestive heart failure, which may occur in the setting of a large hemangioma (see Fig. 14-3, B). Rapid involution is usually completed by 14 months of age. Usually, RICH is managed conservatively. Presence of complications may prompt surgical removal.

NICH, on the contrary, never involutes and may even grow with the child. It usually has an imaging appearance similar to infantile hemangioma, being more homogeneous with uniform parenchymal enhancement.

Most hemangiomas resolve spontaneously, however, approximately 10% to 20% require treatment, which includes pharmacologic, surgical, or laser intervention. Treatment is indicated when functional or cosmetic complications that are worse than the side effects of intervention arise. Lesion size and location, patient age, and phase of the lesion (proliferative, involuting, and mature) also influence the method and timing of intervention.

Kaposiform Hemangioendothelioma

KHE is a rare, aggressive vascular tumor of infancy of intermediate malignancy and differs from hemangioma by histopathology and clinical appearance. The head and neck are uncommon locations. KHE presents as an ill-defined vascular mass with stranding in the subcutaneous fat, intralesional calcifications, and prominent feeding and draining vessels (e-Fig. 14-4). It tends to cause bony destruction and may be associated with the Kasabach-Merritt phenomenon. It should be noted that thrombocytopenia occurs with the rarer KHE and not with the more commonly seen infantile hemangioma.

e-Figure 14-4 Kaposiform hemangioendothelioma.
Axial T2-weighted image shows large, highly infiltrative mass with intralesional calcifications and prominent vessels invading the posterolateral neck spaces.

Tufted Angioma

Tufted angioma is another very rare vascular tumor of early childhood, typically located on the upper back and neck, and can manifest as profound thrombocytopenia. KHE and tufted angioma may represent parts of the same neoplastic spectrum. The GLUT-1 marker can be used to distinguish them from infantile hemangioma if the histologic diagnosis is uncertain. Immunopositivity for GLUT-1 may also be used to separate infantile hemangiomas from congenital hemangiomas, other vascular tumors, and vascular malformations, all of which are negative for this marker.

Venolymphatic Malformations Spectrum

Cervical venolymphatic malformations, similar to venolymphatic malformations located elsewhere in the body, represent a spectrum of entities consisting of a combination of anomalous lymphatic and venous channels. When the lymphatic vascular component is prevalent, lesions are called lymphatic malformations, whereas those with dominant venous components are called venous malformations.

Lymphatic malformations of the neck may be diagnosed prenatally or may present clinically at birth or shortly thereafter. The most pure lymphatic malformation, which seemingly consists of lymphatic channels only, is represented by a fetal posterior neck cystic hygroma. A focal nuchal translucency, perceived as a hypoechoic subcutaneous region in the posterior neck, may be identified on obstetric ultrasonography at 11 to 14 weeks’ gestational age; it is considered a normal finding if it measures below a defined threshold, and eventually involutes by term.

A pathologic cystic hygroma develops in cases of failure of appropriate connections between the lymphatic jugular sac and jugular vein. Such a lesion becomes apparent as nuchal thickening at 18 to 20 weeks’ gestational age. Approximately 60% of nuchal cystic hygromas result from chromosome abnormalities and are associated with aneuploidy syndromes such as Turner syndrome, trisomy 18, trisomy 21, and multiple other syndromes and conditions, including congenital diaphragmatic hernia (Fryns syndrome). Accumulation of lymph may cause lymphedema and nonimmune hydrops, a condition with a high mortality rate.

Ultrasonography demonstrates translucent nuchal thickening, with no identifiable arterial or venous flow by Doppler. MRI reveals focal edema of the posterior fetal neck (e-Fig. 14-5) and, in severe cases, depicts associated lymphedema, pleural effusions, ascites, and anasarca.

e-Figure 14-5 Fetal magnetic resonance imaging of nuchal cystic hygroma.
A sagittal half Fourier acquisition single shot turbo spin echo image of the 19-week-old fetus shows unilocular cystic mass within the posterior fetal neck (arrow) and moderate pleural effusion, compressing the lung.

Lymphatic or venolymphatic malformations of the fetal or neonatal neck represent congenital lesions that may be apparent at birth or may “silently” grow with a child in the first few years before suddenly becoming symptomatic following spontaneous hemorrhage or infection. They usually present as large, transspatial, multicystic masses with intervening septations and fluid–fluid levels (Fig. 14-6, A and B). Ultrasonography demonstrates septated hypoechoic cystic lesions (see Fig. 14-6, C) without internal vascularity, although some vascular flow may be seen within the intralesional septae.

Figure 14-6 Lymphatic malformations.
Fetal magnetic resonance imaging (A, B), fetal ultrasonography (C). Axial half Fourier acquisition single shot turbo spin echo (A) and gradient echo planar imaging (B) scans show a multicystic mass of the lateral neck (thick white arrow) with blood-fluid level (black arrow). The airways remain patent (thin white arrow). Fetal ultrasonography (C) shows hypoechoic multicystic lesion with thick intralesional septations (arrow). Hyperechoic debris indicates blood products.

Lymphatic malformations may have a very complex appearance because of their multi-compartmental nature and internal hemorrhages. Relatively thick intralesional septations or foci of chronic hemorrhage may show enhancement and mimic solid portions of a cystic teratoma. Absence of calcifications and a relatively mild mass effect on surrounding structures despite the large size of the lesion lead to the correct diagnosis. Absence or presence of calcifications is easier to establish on fetal ultrasonography; blood products and calcifications may be occasionally confused on fetal MRI.

Systemic lymphatic malformations include rare conditions known as lymphangiomatosis and Gorham disease (vanishing bone disease). These entities are poorly understood and likely represent a spectrum of congenital disorders of lymphatic development. They manifest by numerous foci of vascular and lymphatic proliferation, involving multiple organs, including bones and lungs (Fig. 14-7 and e-Fig. 14-8), and often cause serious consequences.

Figure 14-7 Lymphangiomatosis.
A coronal magnetic resonance half-Fourier single-shot turbo spin echo image shows large complex cystic masses in the lateral neck, extending into the thorax, and numerous small cysts (arrows) involving the vertebra.

e-Figure 14-8 Gorham disease (vanishing bone disease).
A sagittal magnetic resonance imaging half Fourier acquisition single shot turbo spin echo image through the head (A) and coronal short TI inversion recovery image through the legs (B) show numerous lymphatic malformations (arrows), involving the skull, submandibular neck, and bones and soft tissue of the lower extremities (arrows).

The current approach to treatment of venolymphatic malformations is navigation-assisted interventional sclerotherapy with doxycycline or other sclerosants, which provides excellent results for large macrocystic head and neck lesions. Therapy for microcystic and mixed lesions continues to be a challenge.

Venous Vascular Malformations

Venous malformations represent slow-growing lesions that consist of dysplastic venous channels that may have a minor lymphatic component. They are present at birth but usually manifest clinically later in life.

On imaging, they appear as well-defined, ovoid, heterogeneous lesions with strong enhancement and occasional intralesional phleboliths (Fig. 14-9). A calcified phlebolith may occasionally simulate a flow void on MRI, leading to an erroneous identification of the lesion as a hemangioma. Many lesions may be successfully treated with sclerotherapy, although larger and infiltrative lesions may be more challenging to treat.

Figure 14-9 Venovascular malformation.
A T2-weighted fat-suppressed image shows an ovoid heterogeneous lesion, almost replacing the tongue with numerous hypointense phleboliths.

Teratoma

Even though teratoma is one of the most common tumors of the fetal neck, neck teratomas account for only 5% to 10% of all fetal and neonatal teratomas. Most cervical teratomas are benign, yet it is the most common mass in the fetal neck that has potential to cause fetal demise from airway obstruction. On rare occasions, large vascular teratomas may result in nonimmune fetal hydrops and subsequent fetal death. Teratomas usually originate in the anterolateral neck and may involve the face and cranial base, sometimes extending to the thorax. Interval lesion enlargement in late gestation often causes hyperextension of the neck, which is characteristic of cervical teratoma. The lesion may be intimately associated with the thyroid gland and, in addition to tracheal compression, may cause esophageal compression.

Teratomas are composed of all three germ layers with tissue differentiation that infrequently results in the presence of identifiable organs within these lesions. For instance, an oropharyngeal teratoma (epignathus) often contains identifiable fetal parts; this lesion is usually more aggressive and may grow more rapidly during gestation.

Teratomas are subdivided into mature, immature, and malignant types, each of which differs by histology and hence imaging appearance. Benign mature lesions are mostly cystic, whereas immature lesions tend to be more solid. Malignant teratoma types are uncommonly found in the neck and are less aggressive compared with other locations. Most teratomas demonstrate a combination of cystic and solid components (Fig. 14-10, A to C). Intratumoral foci of hemorrhage and necrosis are suggestive of malignancy. Intralesional fat and calcifications are nearly pathognomonic findings for teratoma but may not always be discernible on fetal MRI and are better seen on ultrasonography. Cervical teratoma and congenital hemangioma share many MRI and ultrasonography features, including interval growth in utero, and establishing the correct diagnosis may be quite challenging. Both imaging modalities are often necessary for optimal assessment.

Figure 14-10 Fetal cervical teratomas.
A, A fetal magnetic resonance imaging (MRI), sagittal half Fourier acquisition single shot turbo spin echo (HASTE) image shows predominantly cystic teratoma (large arrow) with small solid component in the anterolateral neck. Upper airways are distended, but motion of soft palate (small arrow) is preserved. B, A fetal MRI coronal HASTE image shows a complex cervical teratoma with mixture of cystic (white arrow) and solid (black arrow) components. C, A fetal MRI shows mainly solid lesion with small cystic components, extending from the skull base to the upper chest, which appears to encroach the airway. The lesion proved to be a malignant, immature teratoma.

Postnatal imaging of teratomas may include CT, which is helpful for demonstration of osseous involvement. MRI, with or without contrast, is superb for precise depiction of lesion morphology and extension (Fig. 14-11, A). Magnetic resonance angiography may provide crucial information about the vascular supply for surgical planning (see Fig. 14-11, B). Surgical treatment of teratomas may be curative, although the mortality rate remains high. Persistent disfiguration of facial structure, voice issues, and hypothyroidism are among the common complications.

Figure 14-11 Neonatal cervical teratoma.
A, A coronal T2-weighted image with fat suppression shows a very large complex teratoma of the lateral neck with cystic and solid components, internal flow voids, causing severe compression of airways. Endotracheal tube is evident (arrow). B, Neck magnetic resonance angiography shows a large arterial feeder (arrow), originating from the carotid artery, and providing blood supply to the tumor.

Cervical Cystic Lesions

A variety of unilocular cystic neck lesions may be diagnosed on prenatal imaging or may present in neonates. These lesions are uncommon; they originate from different embryonic structures, and their precise diagnosis may be challenging, especially in fetuses. Perinatal cystic neck lesions include dermoid and epidermoid cysts, laryngoceles, foregut duplication cysts, and thymic cysts.

Dermoid and Epidermoid Cysts

Dermoid cysts are congenital benign lesions that contain ectodermal elements, including hair follicles and sweat and sebaceous glands. Cervical dermoids are most commonly seen at floor of the mouth, in the submandibular or sublingual spaces, or at the suprasternal notch. They often demonstrate fatty content with imaging.

Epidermoid cysts are rare congenital unilocular lesions, which may closely resemble a thyroglossal duct cyst; however, a characteristic pattern of restricted diffusion typical for epidermoids helps distinguish these entities. Epidermoid cysts appear earlier, compared with dermoid cysts, with most lesions being evident during infancy (Fig. 14-12, A and B) or diagnosed prenatally (see Fig. 14-12, C). Dermoids and epidermoids have different histologies, but it is not always possible to differentiate them on imaging. It is more important to define the lesion position in relation to the oral floor muscles, as it may guide a surgical approach.

Figure 14-12 Cervical epidermoids.
A, Submandibular unilocular cystic structure with hyperechoic content on ultrasonography and fluid level (arrow). B, Restricted diffusion pattern on magnetic resonance imaging (MRI) diffusion-weighted image. C, Fetal sagittal MRI shows unilocular submandibular epidermoid (black arrow). Airways are patent; hypopharynx is distended (white arrow).

Laryngocele

Most laryngoceles are acquired lesions, seen in middle-aged persons who are involved in activities that cause increased supraglottic pressure. Congenital laryngoceles are rare and likely reflect congenital enlargement of the laryngeal saccule. The three types of laryngoceles are internal, external, and combined laryngoceles. The internal laryngocele is found entirely within the larynx, whereas the external or mixed types protrude through the thyrohyoid membrane and may extend into the lateral neck.

Clinically, laryngoceles may manifest as fluctuating soft tissue masses causing airway obstruction in young infants, or the masses may be diagnosed prenatally (e-Fig. 14-13). Evaluation of a laryngocele with high-resolution cross-sectional imaging depicts the anatomic boundaries of the lesion and the contents of the cyst, which may be filled with air, fluid, or proteinaceous material.

e-Figure 14-13 Fetal laryngocele.
A coronal half Fourier acquisition single shot turbo spin echo image shows a small cystic lesion (arrow) originating from fetal larynx.

Foregut Duplication Cyst

Foregut duplication cysts in the neck may be incidental findings, may present in the neonate with frank respiratory distress secondary to obstruction, or may be diagnosed prenatally as unilocular cystic masses in the anterior compartment of the fetal neck and mediastinum (e-Fig. 14-14). The cyst may or may not communicate with the esophagus; however, thorough search for this communication should be performed. Identification of abnormal canalization of the gastrointestinal tract confirms the diagnosis of foregut duplication cyst.

e-Figure 14-14 Fetal esophageal duplication cyst.
A fetal coronal half Fourier acquisition single shot turbo spin echo image shows a large unilocular cystic structure in the fetal anterolateral neck (large white arrow), which continues into superior mediastinum. Fetal airways appear patent (small white arrow).

Preoperative imaging is recommended to differentiate these lesions from other congenital head and neck masses. Surgical excision with complete removal of the mucosal lining is curative.

Thymic Cyst

Thymic cysts may rarely present within the neck, communicating with pharyngeal structures through the thyrohyoid membrane. Thymic cysts may be found in the midline or anterior to the sternocleidomastoid muscle (e-Fig. 14-15), where they may resemble a branchial arch anomaly.

e-Figure 14-15 Coronal T2-weighted fat-suppressed image shows elongated cystic lesion within the lateral neck (large arrow) extending to the thymus (small arrow).

Cervical Soft Tissue Masses

Ectopic Thymus

Ectopic thymus is usually discovered incidentally on neck imaging performed for unrelated indications. It may be seen anywhere along the course of the primordial thymopharyngeal duct, from the mandibular angle to the thoracic inlet. It is located most often along the carotid sheath but may extend to the midline (Fig. 14-16, A) or may be bilateral. It may be recognized by its imaging characteristics, identical to orthotopic thymus (see Fig. 14-16, B). Ectopic thymus usually resolves with involution of the intrathoracic orthotopic thymus.

Figure 14-16 Ectopic thymus.
A, An axial magnetic resonance imaging T2-weighted image shows unusual retropharyngeal location of ectopic thymus (arrow). B, Ectopic thymus (white arrow) in the right lateral neck of a 1-week-old infant has signal characteristics similar to the visualized orthotopic thymus (black arrow). The lesion elicits no significant mass effect. The airways are patent.

Fetal or Neonatal Goiter

Goiter is a rare cause of fetal neck mass. It may occur in the setting of maternal thyroid disorders such as Graves disease or Hashimoto thyroiditis, or as a manifestation of primary fetal hypothyroidism or hyperthyroidism. Fetal thyroid function may be assessed by ultrasound-guided umbilical cord blood sampling (cordocentesis). The fetal thyroid may be markedly enlarged, causing neck hyperextension, airway obstruction, or compression of the esophagus.

Fetal goiter may be diagnosed on ultrasonography as a bilobed echogenic mass in the anterior neck, with increased vascularity; fetal MRI demonstrates a midline symmetric cervical mass with high signal on T1-weighted imaging (Fig. 14-17). Treatment of fetal goiter includes intra-amniotic thyroxin injection, the main goal being reduction in the size of the goiter and prevention of tracheal obstruction. It may be associated with congenital deafness in the setting of Pendred syndrome (e-Fig. 14-18).

Figure 14-17 Fetal goiter.
A, A fetal magnetic resonance imaging sagittal true fast imaging with steady precession image shows a homogeneous cervical mass (bottom arrow), causing mild distension of hypopharynx. Free motion of soft palate (top arrow) remains preserved. B, A coronal T1-weighted image shows the bilobed uniformly T1-hyperintense lesion (stars), indicative of the iodine content of thyroid gland.

e-Figure 14-18 Pendred syndrome.
A, An axial T1-weighted image through the neck shows large symmetric enlargement of thyroid lobes and isthmus (asterisks), which causes almost complete encasement of the trachea. B, An axial half Fourier acquisition single shot turbo spin echo image through the skull base in the same patient shows bilateral enlargement of vestibular aqueducts (black arrows). The findings of thyroid goiter and congenital deafness are indicative of Pendred syndrome.

Infantile Fibromatoses

Infantile fibromatosis represents a spectrum of rare congenital disorder that involves skeletal and smooth muscles in very young children. It may manifest as a solitary form or as a multicentric form with visceral involvement. Aggressive infantile fibromatosis occurs in the first 2 years of life and may present as a nodular soft tissue mass in the head and neck, with an imaging appearance mimicking infantile fibrosarcoma or hemangioma. A desmoid type of fibromatosis may present as a nodular tumor, which often grows along the nerve sheath or vascular bundle and has a tendency to frequent hemorrhage or necrosis in the central portion, producing a target appearance on imaging (Fig. 14-19). The prognosis is good for solitary neck lesion. These lesions usually stop growing or spontaneously regress.

Figure 14-19 Infantile fibromatosis.
Coronal T2-weighted (A) and sagittal postcontrast (B) magnetic resonance imaging scans show multiple scattered nodular masses (arrows) of the neonatal neck with typical “target” appearance of desmoids type of infantile fibromatosis.

Fibromatosis colli is a benign condition that involves the sternocleidomastoid muscle only. It usually affects neonates and manifests as a hard unilateral soft tissue mass associated with ipsilateral torticollis caused by the muscular contraction and rotation of the chin to the opposite side. Imaging, with ultrasonography or MRI, may be performed if the clinical presentation is unusual. Both modalities reveal diffuse or focal enlargement of sternocleidomastoid muscle (Fig. 14-20) and no discrete mass or lymphadenopathy. Congenital torticollis usually spontaneously resolves in a few months. A child with cervical lymphadenitis and retropharyngeal abscess may present with a postinflammatory torticollis known as Grisel syndrome; this condition is caused by increased ligamentous laxity.

Figure 14-20 Fibromatosis colli.
A, Ultrasonography of a 5-week-old male infant shows fusiform enlargement of the right sternocleidomastoid muscle (cursors). B, A coronal T2-weighted image in another patient shows diffuse thickening and hyperintensity of right sternocleidomastoid muscle (white arrow), associated with ipsilateral torticollis. The left sternocleidomastoid muscle (black arrow) demonstrates normal thickness and signal intensity. (A, Courtesy Brian D. Coley, MD.)

Neonatal Malignancy

Neuroblastoma

Neuroblastoma is a common malignant tumor of childhood. Less than 5% occur within the neck as a primary site, arising in the sympathetic ganglia. Cervical location of neuroblastoma is more common in young infants. This tumor has known association with Horner syndrome.

The imaging of cervical neuroblastoma may be performed with CT or MRI (Fig. 14-21). Both modalities may depict tumor extension, presence of mineralization, and bony or spinal canal invasion. Restricted diffusion pattern on diffusion-weighted MRI confirms the hypercellular, malignant nature of the tumor. Intratumoral dystrophic calcifications are not uncommon and are observed in 50% of cervical neuroblastomas.