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Fig 14.

Axial T1-weighted (A), fat-suppressed T2-weighted (B), and contrast enhanced fat-suppressed T1-weighted (C) MR images of a

child with an arteriovenous malformation. The T2-weighted images (B) show dark, serpiginous flow voids infiltrating the subcutaneous fat of

the right cheek. The contrast-enhanced image (C) reveals an additional soft tissue infiltrating component of the lesion. Multiphasic dynamic

contrast–enhanced MRA images (D-F) reveal early arterial enhancement of the lesion with feeders identified from the external carotid artery.

Note the intralesional nidus formed by the tangle of vessels (E, F).

Arteriovenous Malformation

AVM of the neck presents later in childhood or in the adoles-

cent age group as skin discoloration with or without underlying

compressible (pulsatile) mass. The lesion consists of enlarged

feeding arteries draining into veins without an intervening capil-

lary network. On Doppler US and multiphasic dynamic cMRA

imaging studies, the lesions show a high-flow pattern as impor-

tant differentiating feature from other vascular malformations.

Furthermore, multiphasic time-resolved dynamic cMRA imag-

ing studies may identify dilated feeding arteries and draining

veins, early enhancement of the feeding arteries, and an in-

tralesional nidus with shunting to draining veins and therefore

early venous drainage.

7,8,37

Anatomic MR imaging sequences

demonstrate no well-defined mass, but rather enlarged serpigi-

nous flow voids with an additional soft tissue infiltrating compo-

nent (Fig 14). Evaluation of extension of the lesion and poten-

tial adjacent soft tissue and osseous involvement is important to

determine.

35,36

Mixed-type Vascular Malformation

Mixed-type vascular malformations are less common than

solid-type lesion and mainly comprise mixed veno-lymphatic

malformations; however, other mixed-type lesions may be iden-

tified. These lesions demonstrate clinical features and imaging

characteristics of the involved vascular malformations.

Vascular Tumors

Vascular tumors, particularly infantile hemangiomas, are com-

mon in the pediatric population. These are neoplastic lesions

manifesting with a high endothelial cell turnover. The growth

of these lesions is independent of body size. Various vascular

tumors are encountered in the head and neck region, including

infantile hemangioma, carotid body tumors, glomus jugulare tu-

mors, and juvenile nasopharyngeal angiofibromas (Table 2).

As only hemangiomas potentially present as a neck mass in the

pediatric age group, this entity is discussed in greater detail in

this review.

Infantile hemangiomas represent one of the most common

tumors of infancy with most lesions occurring in the head and

neck (60%). The lesion initially presents as a red superficial skin

lesion in the first couple weeks of life that was not visible at the

time of birth. There is a female predilection with a female to

male ratio of 3:1.

Infantile hemangiomas are benign vascular

neoplasms. Several specific stages have been identified in the

natural course of this entity. In the postnatal time period, the

lesion starts to proliferate and enlarge rapidly and consists of

hyperplastic proliferating endothelial cells (proliferative phase).

At approximately 10 months of age, the hemangioma typically

will gradually start to involute and shows progressive perivas-

cular deposition of fibrofatty tissue (involution phase). About

50% of the lesions are completely resolved by the age of 5

years (involuted phase).

36,37

Favorable locations in the cervical

region include subcutaneous lesions, subglottic lesions, and less

common deep-seated lesions and lesions extending over mul-

tiple tissue planes. Additional infantile hemangiomas may be

identified in approximately 20% of the affected children.

35,36

Imaging reveals the exact anatomic location of the lesion, the

extent of the lesion, and the relation to adjacent structures

(Fig 15). On US, the hemangioma manifests as a well-defined

lobulated heterogeneous lesion with high vascular flow on

Doppler interrogation in the proliferative phase and fibrofatty

features in the involuting phase. The most characteristic MR

imaging feature of a proliferating infantile hemangioma is a

well-defined solid mass that shows avid enhancement in the

arterial phase. Additional multiphasic dynamic time-resolved

Dremmen et al: Imaging Lumps and Bumps of the Neck in Children

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