• 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

o       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

o       Occur when the simple ranula ruptures and is walled off by an inflammatory response

o       Plunging ranulas are pseudocysts partially contained by the remaining epithelium and inflammatory cells that react to irritative saliva

o       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

 

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

 

• Treatment

  • Simple ranulas usually treated with transoral drainage and excision of ipsilateral sublingual gland

  • Plunging ranulas may require more extensive surgical neck dissection