The Neck
Diagnosis | Findings | Comments |
Thyroglossal duct syst | US/CT/MRI: midline cystic mass embedded in infrahyoid strap muscles. Hypodense/intense and anechoic unless infected. If calcified or has solid elements, needs work-up for malignancy. | Most present < 10 y. US confirms normal thyroid gland. CT/MRI if cyst suprahyoid or infected. |
Ectopic thyroid | CT/MRI: Well-circumscribed midline or paramedian tongue mass with density/intensity similar to normal thyroid tissue. Can be multifocal. | May expand rapidly during puberty. Assess normal thyroid tissue as lingual thyroid is only functioning tissue in 75% of cases. |
Dermoid/epidermoid | CECT: cystic, well-demarcated mass containing fluid (epidermoid) or fat/fluid (dermoid). MRI: Use fat-saturated techniques to diagnose dermoid. | Unusual before 5 y of age. Usually involve floor of mouth but if large, can protrude inferiorly. |
Lymph node | US: typical node appearances. | (see Table 4.49 ) |
Cervical thymus | US/MRI: midline or on the left. | (see Table 4.49 ) |
Extension of plunging ranula | US/CT: cystic. MRI: Thin-walled cyst with intermediate signal on T1 and high signal on T2. Bulk of the lesion is in submandibular space with characteristic connection to the floor of the mouth. |
Venolymphatic malformations | MRI: T2 for extent and fluid levels, postcontrast T1 with fat saturation for enhancing septations and venous elements. CT: shows phleboliths. | Usually identified at or soon after birth. US helpful initially to direct further imaging. 1. Lymphatic malformation—transspatial cystic mass uni- or multilocular. 2. Venous malformation—enhancing mass with calcifications. 3. Lymphaticovenous—cystic and enhancing trans-spatial lesion. |
Branchial cleft cyst | US: demonstrates location, usually hypoechoic. CT/MRI: demonstrate infection with enhancing wall/increased attenuation and signal. | Cystic mass posterolateral to submandibular gland, lateral to carotid space, anterior or anteromedial to SCM muscle. |
Abscess Fig. 4.162, p. 394 | US/CT/MRI: fluid-filled mass with irregular, thick enhancing wall and low-density/-intensity center. If involving thyroid, think of fourth branchial pouch anomaly. | Present with symptoms and signs of infection. |
Thymic cyst | US/CT/MRI: Nonenhancing, low attenuation, hypo-/anechoic left lateral neck cyst closely associated with carotid sheath. Solid components rare, represent aberrant thymic/parathyroid tissue. | Can occur anywhere along thymopharyngeal duct but left lateral infrahyoid neck at level of thyroid gland is most common. |
Laryngocoele | Radiograph: shows air-filled lateral structure. Best imaged with CT or MRI, which show unilocular air or fluid-filled cyst. Lies within the submandibular space. | Occur as a result of increased intraglottic pressure. Increase in size with Valsalva. |
(Para) Thyroid cyst | Usually colloid cyst. | (see Table 4.53 ) |
Varix of jugular vein | US: expanded jugular vein with Doppler flow. | Best seen during straining, coughing, or crying. |
Diagnosis | Findings | Comments |
Fibromatosis colli | US: Focal mass in or diffuse enlargement of the middle/lower third of affected SCM muscle. Variable echogenicity. CT: enlarged muscle without discrete mass. MRI: Usually iso-/hypointense to normal muscle on T1. T2 variable but usually hypointense at area of maximal enlargement probably due to fibrosis. | Infant with torticollis tilting head to same side and rotating head toward opposite side. |
Lymph nodes/lymphoma | US: Oval nodes increased in size and number. Central hypoechogenicity in suppuration. CECT: best to differentiate cellulitis/phlegmon/abscess and assess extent of disease in suspected malignancy. MRI: T1 low/intermediate signal; T2 high signal. | Findings nonspecific and depend on clinical scenario; often rely on tissue diagnosis. |
Teratoma Fig. 4.130, p. 378 | CT/MRI: Large and infiltrative with multiple cystic and solid elements. Contain fat and calcification. Both modalities show extent and components. | Usually < 1 y; may cause significant airway and feeding compromise. |
Neuroblastoma | CT/MRI: Well-defined mass lying posterior to the vascular sheath and occasionally extending into the cervical spinal canal. MRI is best for delineating extent of tumor and spinal and intracranial extent. | Less than 5% occur in the neck. Need chest and abdomen CT as part of initial work-up to rule out abdominal primary. |
Hemangioma | US: well-defined mass with prominent vessels. MRI: Best for extent. T1 isointense to muscle with intense enhancement postcontrast; T2 hyperintense with multiple flow voids. | Characteristic presentation; therefore, imaging indicated if suspect deep extension, pretreatment, or to assess treatment response. |
Rhabdomyosarcoma | CT: heterogeneous lesion with or without osseous destruction. MRI: isointense to muscle on T1, hyperintense on T2 and show enhancement postcontrast. | May be a primary lesion or related to metastatic adenopathy that is present in 50% of patients. Forty percent occur in head and neck. |
Fibrosarcoma/sarcoma | CT/MRI: Heterogeneously enhancing soft-tissue mass. Usually less intense and homogeneous enhancement than hemangioma. May show osseous destruction. | Often with regional lymph node involvement. Need chest CT for metastatic surveillance. |
Hematoma | US: Imaging findings depend on age of bleed. Acute bleed hyper-echoic, less echogenic in 96 h, and eventually anechoic. Usually well defined but may become irregular if blood escapes into adjacent structures. Differentiate from tumor by absence of flow. | Usually due to trauma, anticoagulation, or coagulopathy. |
Neurofibroma/plexiform neurofibroma | MRI: T2 hyperintense with hypointense center (target sign). Heterogeneous CE. | MRI best for tumor extent, especially when close to spine. Assess for other manifestations of NF. |
Brachial plexus schwannoma | MRI: Well-circumscribed, fusiform, T2 hyperintense enhancing mass between anterior and middle scalene muscles. T1 isointense. CT: Isodense to muscle, calcification uncommon, moderate enhancement. Smooth, corticated widening of bony neural foramen. | Painless, slow-growing mass in neck. May be indistinguishable from neurofibroma. |
Cervical thymus | CT/MRI: At cervicothoracic junction, midline or to the left. Mimics appearance of normal thymus on all imaging modalities, and MRI may show connection with the mediastinal thymus. | Incomplete thymic descent, usually asymptomatic but may cause dysphagia. |