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A ranula is a mucous retention cyst that arises from the sublingual gland (or adjacent minor salivary glands) due to ductal obstruction or rupture. It typically develops in the sublingual space of the floor of the mouth.

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Etiopathogenesis

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Obstruction of the sublingual gland duct leads to extravasation of mucus into the surrounding tissues, forming a cyst-like cavity lined by granulation tissue rather than true epithelium (pseudocyst).

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Types:

Simple ranula – Confined to the sublingual space, presenting as a bluish, translucent, fluctuant swelling in the floor of the mouth.
Plunging ranula – Herniates through or around the mylohyoid muscle into the submandibular space, presenting as a submandibular neck swelling.

Clinical Features

Painless, slow-growing, cystic swelling in the floor of the mouth (usually lateral to the midline).
May cause dysphagia, speech disturbance, or airway compromise if large.
Plunging ranula presents as a cervical swelling below the mandible without prominent intraoral component.

Radiology

Modality	Imaging featyres
US	Anechoic or hypoechoic cystic lesion with posterior acoustic enhancement.
CT	• Well-defined, low-attenuation cystic lesion in the sublingual space
• Plunging ranulas extend into the submandibular space through a defect or around the posterior margin of the mylohyoid muscle.
MR	• Homogeneously hyperintense on T2WI and hypointense on T1WI
• Better delineates extension into adjacent spaces.

![Simple ranula. a Axial and b coronal CECT images demonstrate a well-circumscribed fluid attenuation lesion within the left sublingual space (*)

Patel, S., Bhatt, A.A. Imaging of the sublingual and submandibular spaces. Insights Imaging 9, 391–401 (2018). https://doi.org/10.1007/s13244-018-0615-4](attachment:a190d61d-0c0c-4a5f-a07a-fd495d773407:image.png)

Simple ranula. a Axial and b coronal CECT images demonstrate a well-circumscribed fluid attenuation lesion within the left sublingual space (*)

Patel, S., Bhatt, A.A. Imaging of the sublingual and submandibular spaces. Insights Imaging 9, 391–401 (2018). https://doi.org/10.1007/s13244-018-0615-4

![Plunging ranula. Axial CECT images of the floor of the mouth illustrates a well-circumscribed cystic lesion predominantly occupying the left submandibular space causing a mass effect on the left submandibular gland (a, arrow). A more superior image reveals a small portion of the lesion based in the sublingual space, referred to as the “tail sign” (b, arrowheads)

Plunging ranula. Axial CECT images of the floor of the mouth illustrates a well-circumscribed cystic lesion predominantly occupying the left submandibular space causing a mass effect on the left submandibular gland (a, arrow). A more superior image reveals a small portion of the lesion based in the sublingual space, referred to as the “tail sign” (b, arrowheads)

Patel, S., Bhatt, A.A. Imaging of the sublingual and submandibular spaces. Insights Imaging 9, 391–401 (2018). https://doi.org/10.1007/s13244-018-0615-4

Differentials

Dermoid/epidermoid cysts (usually midline)