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Ranula: Definition, Types & Etiopathogenesis - Frog Under Tongue

  • Definition:
    • Mucocele on floor of mouth, from sublingual gland (common) or minor salivary glands.
    • Appearance: Bluish, translucent, fluctuant swelling.
    • 📌 "Rana" = frog (resembles frog's belly). Oral ranula showing bluish translucent swelling
  • Types:
    • Oral (Simple):
      • Above mylohyoid muscle, confined to mouth floor. Most common.
    • Plunging (Cervical):
      • Extends through mylohyoid into neck (submandibular space).
      • May be neck mass +/- oral swelling. "Tail sign" on imaging (CT/MRI).
  • Etiopathogenesis:
    • Extravasation (Most Common): Trauma → mucus spillage → pseudocyst (no epithelial lining).
    • Retention (Rare): Duct obstruction → ductal dilation → true cyst (epithelial lining).

⭐ Most ranulas originate from the sublingual gland and are pseudocysts due to mucus extravasation following trauma.

Ranula: Clinical Features & Diagnosis - Spotting the Swell

  • Clinical Presentation:
    • Oral Ranula:
      • Soft, fluctuant, dome-shaped, bluish, translucent swelling.
      • Location: Floor of mouth, lateral to midline.
      • 📌 "Frog's belly" appearance (rana = frog).
      • Usually painless; large ones may cause speech/swallowing issues.
    • Plunging/Cervical Ranula:
      • Extends into neck via mylohyoid muscle defect/dehiscence.
      • Presents as soft, painless neck mass; oral component variable.
  • Diagnostic Approach:
    • Clinical Exam: Characteristic appearance & consistency. Transillumination often positive. Bimanual palpation for plunging type.
    • Imaging:
      • USG: Initial assessment for cystic nature & superficial extent.
      • CT/MRI: Define full extent, especially for plunging type, and relation to mylohyoid muscle.
        • "Tail sign" (fluid extension from sublingual space) is a key diagnostic feature of plunging ranula. Plunging ranula with tail sign on MRI
    • Fine Needle Aspiration (FNA):
      • Yields viscous, mucoid, straw-colored (salivary) fluid.
      • Biochemistry: ↑ Amylase, ↓ protein content.
    • Histopathology (post-excision): Confirms pseudocyst (lacks true epithelial lining; wall of granulation/fibrous tissue).

⭐ The "tail sign" on CT or MRI, representing the extension of the ranula from the sublingual space into the submandibular or parapharyngeal space posterior to the mylohyoid muscle, is a key diagnostic feature of plunging ranulas originating from the sublingual gland.

Ranula: Management & Differential Diagnosis - Evicting the Frog

Management

  • Surgical Options:
    • Marsupialization: Creates a pouch; high recurrence.
    • Excision of Ranula: Removal of the cyst.
    • Excision of Sublingual Gland (± Ranula): Gold standard, lowest recurrence, especially for plunging ranulas.
    • Sclerotherapy: OKP-432 (Picibanil), bleomycin.
    • CO2 Laser: Vaporization or excision.

Differential Diagnosis (DDx)

  • Floor of Mouth Swellings:
    • Dermoid cyst / Epidermoid cyst
    • Sublingual abscess
    • Hemangioma / Lymphangioma
    • Lipoma
    • Salivary gland neoplasm (rare in sublingual gland)
    • Cystic hygroma (especially for plunging ranula)
    • Thyroglossal duct cyst (if midline & plunging)
    • Branchial cleft cyst (2nd arch, if lateral cervical)

Exam Favourite: Complete excision of the ipsilateral sublingual gland is the definitive treatment with the lowest recurrence rate for both oral and plunging ranulas.

📌 Mnemonic for DDx: "Real Doctors Hate Lame Students Crying"

  • Ranula
  • Dermoid/Epidermoid cyst
  • Hemangioma/Lymphangioma
  • Lipoma
  • Sublingual abscess/Sialolithiasis
  • Cystic hygroma/Neoplasm

High‑Yield Points - ⚡ Biggest Takeaways

  • A ranula is a mucocele specifically from the sublingual gland, appearing as a bluish swelling in the floor of the mouth.
  • Plunging ranulas dissect through the mylohyoid muscle into the neck.
  • Histologically, it's a pseudocyst (lacks an epithelial lining).
  • Treatment includes marsupialization, excision of the ranula, or excision of the sublingual gland.
  • Often painless; may become symptomatic if large or infected.
  • Consider dermoid cyst and lymphangioma in differential diagnosis_

Practice Questions: Ranula

Test your understanding with these related questions

Plunging ranula refers to a mucocoele that has penetrated which muscle?

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Flashcards: Ranula

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The _____ is progressively pushed upwards and backward threatening the airway, in Ludwig's angina

TAP TO REVEAL ANSWER

The _____ is progressively pushed upwards and backward threatening the airway, in Ludwig's angina

tongue

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