Plunging ranula

3 year old girl presented with a painless swelling noticed below the right jaw line. It has been slowly increasing in size over the last 9 months. Ultrasound revealed a multiseptated cystic lesion in the floor of mouth. MRI was done for further evaluation.





Axial T2 fat sat
Axial post contrast fat sat T1


  • Fluid collection is seen epicentered in right sublingual space extending posteriorly beyond mylohyoid into the submandibular space and superiorly into right parapharyngeal space along the lateral margin of right tonsil.
  • T2 hyperintense, T1 iso to hyperintense fluid with thin septae and facilitated diffusion. Minimal septal enhancement.
  • No extension into other neck spaces.

Key points

  • Cystic lesions with communication to sublingual space – always ranula has to be the first differential.
  • In the absence of sublingual involvement, differentials to consider would include
    • cystic hygroma
    • branchial cleft cyst
    • epidermoid

Read more

  1. Radiopaedia – ranula.
  2. Macdonald, Andre J., Karen L. Salzman, and H. Ric Harnsberger. “Giant ranula of the neck: differentiation from cystic hygroma.” American journal of neuroradiology 24.4 (2003): 757-761