Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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March 22, 2010
Diving (Plunging) Ranula
- Ranulas are retention cysts resulting from trauma or inflammation of sublingual gland or minor salivary gland in sublingual space (SLS). When large, simple ranula ruptures along posterior margin of mylohyoid muscle into submandibular space (SMS) creating a pseudocyst lacking epithelial lining termed diving ranula.
- Size: < 6 cm; may be giant
- Morphology: Comet-shaped mass with "tail" in collapsed SLS and "head" in posterior SMS.
- CT: low density unilocular or multilobular mass emanating from SLS extending into adjacent SMS +/- inferior parapharyngeal space. Subtle wall enhancement. If infected, distended with thick, enhancing wall. CECT best for defining extent of ranula.
- MRI: T2 hyperintense, T1 C+ shows wall enhancement (thick f infected).
- Presentation: painless swelling SMS, 50% known preceding trauma. Median age 30 years.
- Tx: removal of sublingual gland via cervical approach. Surgical rupture common but does not increase risk for recurrence. Some success with hydrodissection or sclerotherapy with intracystic OK-432 injection.