Diagnostic ultrasound ( PDFDrive )

1636 PART V Pediatric Sonography
A
B
FIG. 48.15 Human Immunodeiciency Virus (HIV) Parotitis. (A) Transverse images of mildly enlarged right and left parotid glands containing
small, hypoechoic areas. (B) Coronal postgadolinium T1-weighted magnetic resonance image demonstrates multiple lymphoepithelial cysts within
enhancing parotid tissue bilaterally.
Masses
Vascular Masses. he common childhood salivary gland
vascular masses include vascular neoplasms such as hemangiomas,
and vascular malformations such as venous or lymphatic malformations.
Hemangiomas represent 60% of all salivary gland
neoplasms. 46,47 About 80% arise in the parotid, and 18% are
present in submandibular tissue. 20 On ultrasound, the lesions
are iniltrative or well circumscribed, usually hypoechoic relative
to the glandular tissue, and may involve all or part of the gland
(Fig. 48.16). In the proliferative phase, on color Doppler sonography
there is a high vessel density, with both increased arteries
and increased veins. Arterial spectral Doppler demonstrates high
low velocity and low resistive index (RI) with spectral broadening.
43,47 Because most infantile hemangiomas spontaneously
regress, medical management with propranolol, laser therapy,
or surgical excision is used only when symptoms warrant. 48,49
Lymphatic malformations may involve the parotid gland or
may iniltrate the submandibular space. On ultrasound, a
lymphatic malformation within the parotid gland shows cystic
spaces of varying sizes, with or without solid elements, septations,
and internal layering debris 11 (Fig. 48.17). Venous malformations
can be small, involving only a portion of the salivary gland, or
may be difuse, involving multiple spaces of the neck. hese
lesions contain multiple cystic areas, ectatic venous channels,
and oten phleboliths, which aid in sonographic diagnosis.
Neoplasms. Tumors of the salivary glands account for only
1% of all pediatric tumors. 50 About 8% of primary tumors of the
head and neck in children originate within the salivary glands 15 ;
90% to 95% occur in the parotid and the rest in the submandibular
and sublingual glands. 11 Most masses of the salivary gland are
benign and have a vascular etiology, with only 13% reported to
be solid salivary gland tumors. 20,50,51 Pediatric epithelial salivary
masses tend to occur in children older than 10 years, with 23%
to 50% of them reported to be malignant. 18,20,50 Most malignant
tumors in children are of lower grade compared with adults,
although children younger than 10 years tend to have higher
grade tumors. 20
In children, sonography is the irst step, especially for palpable
lesions because the majority of space-occupying lesions in the
salivary glands are well delineated. 23 here are no speciic sonographic
indings diferentiating malignant from benign salivary