Signs and Symptoms
- Translucent, blue, dome-shaped, fluctuant swelling in the tissues of the floor of the mouth
- May interfere with swallowing (dysphagia) if it becomes large
- Non-painful, unless it becomes infected
- Usually located lateral to the midline
- Can also present as a swelling in the neck (cervical ranula)

Complications
- Infection
- Repeated trauma
- Bursting and reformation
- Dysphagia (in the case of a large ranula)
- Difficulty in detecting due to rapid fluctuation in size

Causes
- Minor trauma to the floor of the mouth
- Mucous extravasation cyst (mucocele) of the floor of the mouth
- Can arise from sublingual salivary gland, submandibular duct, or minor salivary glands
- Cervical ranula occurs when spilled mucin dissects through the mylohyoid muscle
- Rarely, ranulae may extend into the parapharyngeal space

Mechanism
- Fluid within a ranula has a viscous, jellylike consistency

Diagnosis
- Histologic appearance similar to mucoceles from other locations
- Granulation tissue formation containing foamy histiocytes
- Ultrasound and magnetic resonance imaging may be useful for imaging
- Clinical examination may be required to distinguish from a small squamous cell carcinoma obstructing the Wharton duct
- Criteria for diagnosis include age (mostly seen in young children and adolescents), location, size, color, surface, tenderness, fluctuation test, transillumination test, and presence of enlarged cervical lymph nodes or neck prolongation