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25-Year-Old Woman with Oral Fullness
This case features a 25-year-old woman presenting with oral fullness, ultimately diagnosed with bilateral simple ranulas.
Imaging overview:
Coronal STIR imaging demonstrates well-defined bilateral sublingual space cystic lesions located superior to the mylohyoid sling, lateral to the midline root of the tongue. Axial T2 fat-saturated imaging confirms the lesions are fluid signal intensity and confined to the bilateral sublingual spaces. Axial T1 fat-saturated post-contrast imaging shows thin rim enhancement around the cysts without internal enhancement, consistent with simple ranulas.
Clinical insight:
Ranulas are mucous retention cysts arising from the sublingual glands. A simple ranula is confined above the mylohyoid muscle within the sublingual space. When a ranula extends inferiorly through or around the mylohyoid muscle into the submandibular or other deep neck spaces, it is classified as a diving or plunging ranula. Bilateral ranulas, as in this case, are uncommon. On MRI, ranulas follow fluid signal intensity on all sequences, and contrast-enhanced studies may demonstrate a thin rim of peripheral enhancement. Awareness of the mylohyoid muscle as the anatomic boundary distinguishing simple from diving ranulas is essential for accurate classification and surgical planning.
Case courtesy of Madison Gardner, MS, and Rick Wiggins, MD, University of Utah Health.