Diagnostic ultrasound ( PDFDrive )

CHAPTER 48 The Pediatric Head and Neck 1655
malformations, based on lesion growth patterns. Vascular masses
that proliferate rapidly and can involute are regarded as tumors. 48
Vascular lesions that grow in proportion to the child and do not
involute are considered malformations. With emerging knowledge
about these vascular lesions, the International Society for the
Study of Vascular Anomalies (ISSVA) provided a classiication
on vascular anomalies in 1996, and updated it in 2014. hey
acknowledge the fact that this classiication scheme would be
modiied as new scientiic information became available. 162
Vascular Anomalies 162
VASCULAR TUMORS
Benign
Locally aggressive or borderline
Malignant
VASCULAR MALFORMATIONS
Simple
Combined
Of major named vessels
Associated with other anomalies
Gray-scale and color and duplex Doppler ultrasound can
help determine whether the anomaly is cystic or solid, evaluate
for intralesional calciications or phleboliths, and identify the
presence of high-low vessels. 163 CT scans may be helpful when
a patient cannot be sedated, to conirm intralesional calciication
and evaluate associated bone changes. Because of sot tissue
deinition, multiplanar capabilities, and ability to deine highlow
vessels, MRI is the preferred imaging modality for vascular
malformations. 161,163
Vascular Tumors
Benign vascular tumors include infantile and congenital hemangiomas,
pyogenic granuloma (lobular capillary hemangioma),
tuted angioma, and a few other rare lesions. Kaposiform
hemangioendothelioma is a locally aggressive vascular tumor
seen in infants. Angiosarcoma and epithelioid hemangioendothelioma
are malignant vascular tumors that may be seen in
childhood. 162 he locally aggressive or malignant vascular lesions
are extremely rare and frequently characterized by rapid growth.
hese lesions are best evaluated with MRI.
Infantile hemangiomas are the most common vascular lesions
in infancy and childhood. hese high-low masses are benign
neoplasms composed of proliferating endothelial cells. 161 Infantile
hemangiomas represent 60% of head and neck hemangiomas. 47
Hemangiomas occur three times more oten in girls than boys. 48
Most occur as a painless, compressible, growing mass, and half
have a bluish or red stain in the skin supericial to the lesion. 157
hese lesions typically become apparent within the irst few weeks
of life, undergo a phase of proliferation and peak in size at 1
year of age, then undergo spontaneous, slow involution over the
irst decade. 161 On ultrasound, these lesions are lobulated, well
marginated, heterogeneously echogenic and compressible when
supericial. On color Doppler imaging during the proliferative
phase, there is exuberant vascularity within the lesion, with high
vessel density of greater than ive vessels per square centimeter 164
(Fig. 48.47, Video 48.3). hese lesions are supplied by high-low
vessels with low-resistance arterial waveforms. Prominent draining
veins are present, but there is no arterialization of venous
waveforms. 164 Clinical and sonographic evaluation is generally
suicient for diagnosis, and biopsy is rarely indicated. During
the involutional phase, there is a decrease in size of the lesion
as well as a decrease in the vascularity and the high systolic
low. 164
Hemangiomas are common in premature infants, usually
evident shortly ater birth, but 95% of these lesions manifest
during the irst 6 months. 157,163 Endothelial glucose transporter
1 (GLUT 1) is a diagnostic marker for infantile hemangioma. If
one or multiple hemangiomas are present in a trigeminal dermatome
distribution (frequently V1), the clinician should consider
PHACES syndrome (posterior fossa malformations, hemangiomas,
arterial anomalies, coarctation of aorta and cardiac defects,
eye abnormalities, sternal notching). 165 Infantile hemangiomas
are treated only if symptomatic or if they endanger vital structures.
Treatment options include propranolol, laser therapy, and surgery.
Congenital hemangiomas, less common than infantile hemangiomas,
will be present at full size at birth. hey are GLUT 1
negative, lack a gender predisposition, and commonly occur in
the head or extremity joints. 166 hey may subsequently involute
before 1 year of age (rapidly involuting congenital hemangioma
[RICH]), may be static (noninvoluting congenital hemangioma
[NICH]), or may partially involute (partially involuting congenital
hemangioma [PICH]). On Doppler sonography, congenital
hemangiomas are heterogeneous and highly vascular with fast-low
low-resistance arterial vessels as well as channels with venous
low 166,167 (Fig. 48.48). Calciications may occasionally be seen
in RICH and NICH, diferentiating these lesions from infantile
hemangiomas. 166
Vascular Malformations
Simple vascular malformations may be composed of only one
type of vessel such as capillaries, lymphatics, or veins or, as in
the case of arteriovenous malformations (AVMs) or arteriovenous
istulas (AVFs), may involve more than one type of vessel. 162
Simple capillary malformations frequently appear as cutaneous
lesions, are diagnosed clinically, and are rarely imaged. Capillary
malformations can occur combined with other anomalies, such
as the Sturge-Weber syndrome with facial cutaneous capillary
malformation (port-wine stain) frequently in the distribution
of the ophthalmic segment of the trigeminal nerve. 162
Lymphatic malformations, originating from a sequestered
embryonic lymph sac, are composed of primitive lymphatic spaces
of varying sizes separated by connective tissue stroma. 140 Lymphatic
malformations may be macrocystic with large cysts
(previously called cystic hygromas), microcystic (previously
called lymphangiomas), or mixed cystic. here is no speciic
size criterion separating microcystic from macrocystic lymphatic
malformations, but in general, if the size of the cyst is large
enough for sclerotherapy, it is considered macrocystic. Lesion
cyst size is likely caused by the stromal environment rather than
lesion behavior. 99 Some lymphatic malformations are diagnosed