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Fig 15.
Axial T1-weighted (A), fat-suppressed T2-weighted (B), and contrast-enhanced fat-suppressed T1-weighted (C) MR images of a child
with an infantile hemangioma. The T2-weighted image (B) shows a well-defined hyperintense mass in the left carotid space with transspatial
infiltrative extension. Flow voids are present in the mass. Multiphasic dynamic contrast–enhanced MRA images (D-F) demonstrate avid
enhancement in the arterial phase (D). The arterial feeders and venous drainage of the mass lesion can easily be identified (D, F).
cMRA imaging studies may show prominent arterial feeders
and draining veins of these solid tumors. The lesion shows an
isointense to slight hyperintense T1 signal and hyperintense T2
signal. In the involuting, phase elements of the lesion may be
replaced by fatty tissue.
7,8,35
Acquired Cystic Masses
Ranula
Ranulas are not common in the pediatric age group. The peak
frequency is in the second decade. Incidentally, congenital mu-
coceles and ranulas have been reported.
38
There is a slight fe-
male predilection for oral ranulas and a predilection for males
for cervical ranulas.
39
A ranula is a mucous retention cyst (mu-
cocele) or pseudocyst arising from salivary extravasation from
a sublingual gland or minor salivary gland into the surrounding
soft tissues of the oral cavity or neck. The extravasation is in
the vast majority the consequence of infection, inflammation,
or trauma to the involved gland causing an occluded gland
duct. Ranulas are categorized into simple (oral) ranulas with a
peripheral epithelial layer or plunging/diving (cervical)
ranulas.
40,41
A plunging ranula is the consequence of a ruptured
simple ranula and therefore lacks an epithelial lining (pseudo-
cyst). The lesion manifests as a swelling in, respectively, the
floor of the mouth or the submandibular space. The location of
both simple and plunging ranulas is typically off midline. Sim-
ple ranulas appear in the sublingual space in or superficial to the
mylohyoid sling. US demonstrates a thin-walled ovoid or lobu-
lated cyst with or without debris deep to the mylohyoid muscle.
MR imaging features consist of a T2 hyperintense cystic lesion
in the sublingual space with variable T1 intensity depending
on the amount of protein in the cyst (Fig 16). Plunging (rup-
tured) ranulas tend to extend posteriorly from the sublingual
space into the submandibular space. Less commonly, the lesion
Fig 16.
Axial T2-weighted (A), coronal T2-weighted (B), and sagittal fat-suppressed T2-weighted (B) MR images of a child with a large
plunging ranula. The axial image (A) demonstrates a large thin-walled cystic structure in the floor of the mouth. The coronal image (B) shows
posterior extension of the cystic structure from the sublingual space into the left submandibular space. The maximal volume of the plunging
ranula is localized in the submandibular space. Note the layering debris due to protein-rich material in the cyst on the sagittal image (C).
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