Ranula

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).
• 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.
  • 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_