2017 Sec 1 Green Book

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

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

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

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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