Learning Radiology xray montage

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