Ranulas and Plunging Ranulas Workup

Updated: Dec 07, 2017
  • Author: Brent Golden, DDS, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Workup

Imaging Studies

CT scanning

Ranulas on CT scanning (as seen in the image below) are described as cystic masses in the submandibular or parapharyngeal space that extend into or abut the sublingual space. On CT scanning, they are noted to be sharply demarcated lesions of low attenuation that conform to their local fascial boundaries. They are generally unilocular in nature. With the exception of a sublingual epidermoid, the appearance of a simple ranula on CT scanning is distinctive. [5]

CT scan of ranula. CT scan of ranula.

Plunging ranulas are occasionally noted on CT scanning to have a small tail extending into the sublingual space. This finding is almost pathognomonic for plunging ranulas. If this is absent, the presence of a homogeneous cyst in the submandibular or parapharyngeal space that abuts the sublingual space is highly indicative of a plunging ranula.

MRI

MRI is the most sensitive imaging study to evaluate the sublingual gland and its pathologic states. On T1-weighted MRI scans, the gland appears as an area of intermediate signal intensity, lower than adjacent fat but higher than muscle. T2-weighted images help discriminate cysts from surrounding normal structures. [6]

Ultrasonography

High-resolution ultrasound is a noninvasive test with no known biologic cost that has been demonstrated to be quite successful in evaluating cystic lesions of the submandibular region in young people, with particular utility in the plunging ranula. In addition to confirming the cystic nature of the lesion, the mylohyoid muscle integrity also can be elucidated. [7]

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Diagnostic Procedures

Needle aspiration findings are as follows:

  • Analysis of fluid from ranulas demonstrates mucus with prominent histiocytes.

  • The biochemistry of this fluid shows high amylase and protein content.

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Histologic Findings

Most ranulas demonstrate a cyst devoid of epithelial lining, with the wall composed of vascular fibroconnective tissue resembling granulation tissue. Histiocytes predominate the pseudocyst wall. Mucin and foamy macrophages are often observed. Occasionally, partial epithelial linings are observed.

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