Ranula
Submitted by Tony Chang, MD

• Mucus retention cyst that occurs in the sublingual gland
• Ranulas do not communicate with the duct
• Etiologies include
• Prior trauma, usually iatrogenic from prior surgery
• Obstruction of  the sublingual gland or its duct
• Two types of ranulas
• Simple
• Plunging
• Simple ranulas are true cysts
• Occur in floor of the mouth above the level of the mylohyoid with a lining formed by the sublingual gland capsule
• Plunging/deep/diving ranulas
• Occur when the simple ranula ruptures and is walled off by an inflammatory response
• Plunging ranulas are pseudocysts partially contained by the remaining epithelium and inflammatory cells that react to irritative saliva
• Plunging ranulas usually extend below the level of the mylohyoid
• Clinical findings
• Both types present as a painless mass in the sublingual space
• Plunging ranulas extending inferiorly into the submental or submandibular space
• Imaging findings
• Typical CT findings include
• Smooth, well delineated, cystic lesion
• Splaying the genioglossus and mylohyoid with a uniformly thin, non-enhancing wall
• Ranulas can be slightly increased in attenuation especially the higher the protein content within the fluid
• Infected ranulas may have thickened enhancing walls and cannot be distinguished from an abscess
• MRI findings
• Low signal intensity on T1 weighted imaging
• High signal intensity on T2 weighted imaging but varies with protein content
• Treatment
• Simple ranulas usually treated with transoral drainage and excision of ipsilateral sublingual gland
• Plunging ranulas may require more extensive surgical neck dissection

 
Ranula. CT scan shows a large mucous
retention cyst arising from the sublingual gland (ranula)

Som and Curtin, Head  and Neck Imaging