Exodontia.Info
Ranula

A ranula (Latin word rana, meaning frog) describes a blue, translucent swelling in the floor of the mouth,
reminiscent of the underbelly of a frog.  It is an uncommon type of mucus-filled cyst (
mucocœle) arising
from the
sublingual or submandibular salivary glands in the floor of the mouth.
Ranulas / Ranulæ & Their Treatment
Photos of ranulæ  present in the floor of the mouth, either occupying
both sides (opposite) or just one side (below).
The structure is essentially the same as other mucocœles, though there is usually an epithelial lining (i.e. lined by
‘skin’).

Ranulæ are usually either one-side or the other in the floor  of the mouth and 2 - 3 cm in diameter.  Occasionally,
they extend across the whole of the floor of the mouth.

A
ranula is most commonly observed as a bluish cyst located below the tongue.  It may fill the mouth and raise the
tongue.  Typically, these are painless masses that do not change in size in response to chewing, eating or
swallowing but may interfere with these functions (speech or chewing / eating).  Occasionally, pain may be involved.

Ranulæ are rare.  In one study of 1303 salivary gland cysts, only 42 were
ranulæ.  The reported male-to-female
ratio of occurrence is 1:1.3.  
Ranulæ tends to occur most frequently in the second and third decades of life, with an
age range of 3 - 61 years.


Ranula Formation

Ranulæ are formed from 1 of 2 processes:

1.        Partial obstruction of a
sublingual duct can lead to formation of an epithelial-lined retention cyst.  This is
unusual, occurring in less than 10% of all ranulæ.

2.        Trauma can lead to formation of
ranulæ.  With trauma, if a duct is obstructed, secretory back-pressure
builds leading to
salivary duct rupture with mucus being forced into the surrounding tissues.  Alternately, trauma
causes direct damage to the duct or
acini, leading to mucus extravasation - a pseudocyst then forms.  The more
appropriate term for this may be
Mucus Escape Reaction (MER).


Ranula Investigations

MRI is the most sensitive imaging study to evaluate the sublingual gland and its pathologic states.

Sublingual glands and their pathologic states are difficult to visualise with ultra-sound.

Obtaining a specimen for pathology is essential, not only for histologic confirmation but also because the presence
of
squamous cell carcinoma arising in the cyst wall of a ranula and papillary cystadenocarcinoma of the
sublingual gland
presenting as a ranula have been reported.


Medical Treatment

A recent though small study evaluated the effectiveness of orally administered Nickel Gluconate-Mercurius Heel-
Potentised Swine Organ Preparations D10/D30/D200
, a homo-toxicological agent.

This medication acts to stimulate
pseudocyst re-absorption and glandular repair and aids in improving the
physiologic functioning of the gland.  In this study,
Nickel
Gluconate-Mercurius Heel-Potentised Swine Organ Preparations D10/D30/D200
was administered regularly from
6 weeks to 6 months.  Eight out of 9
ranulæ
responded to medical therapy.


Surgical Treatment

Marsupialisation:  Simple marsupialisation is the oldest and most widely reported treatment for ranulæ.  It involves
'unroofing' the
cyst and tacking the edges of the cyst to adjacent tissue.

Failure rates range from 61 - 89% with
cysts recurring anywhere from 6 weeks to 12 months later.

Inferior compression on the cyst from the tongue leads to premature closure of the opened cyst leading to the high
recurrence rates.  When conventional
marsupialisation is undertaken, the wound margins tend to be in contact with
each other because of the narrow space and the movement of the tongue and the floor of the mouth.  As a result,
the
ranula tends to re-form and recur.

Packing the
cyst cavity with gauze for 7 - 10 days improves the success rate.

Placement of suture / stitch or Seton:  A silk suture or Seton can be placed through the surface of the cyst under
local anæsthesia.  This is left in place while an epithelial tract forms, to allow for mucus drainage between the
surface and the underlying
salivary glandular tissue.

Morbidity is minimal to non-existent and success has been good in limited studies.

Sclerosing Agents:  Bleomycin and OK-432 have been used with success in treatment of ranulæ.

In
one study, 31/32 patients (97%) achieved a disappearance or marked reduction in ranula size with injection of
OK-432.  Nearly half of all patients experienced local pain or fever which resolved over several days.  Intra-cystic
injection therapy
with OK-432 is relatively safe and can be used as a substitute for surgery in the treatment of
ranulæ.  Intra-cystic sclerosing injection with OK-432 has been proposed as a ranula primary treatment.

CO2 Laser: The CO2 laser has been used with a limited number of patients with good success to remove the cyst
and scar the gland enough to decrease risk for recurrence.

Post-operative follow-up at 6 months showed no recurrence, no
lingual nerve dysæsthesia, no ductal disruption and
only minimal scar formation.

Radiation Therapy: In the rare patient who cannot tolerate surgery, radiation therapy is a viable alternative.  Low
doses are effective.  
Xerostomia (dry mouth) can be avoided with low-dose therapy and shielding of the opposite
side
parotid gland.  The risk of radiation-induced malignancy is real but small.

Sublingual Gland Excision: The 'gold-standard' treatment for ranulæ is the excision of the ranula & the sublingual
gland
.  This removes the source of the mucus and thus significantly decreases the risk for recurrence.

A
ranula larger than 1 cm should be treated by removal of the offending sublingual gland; other authors have
proposed that this treatment be used regardless of the size of the lesion.

Marsupialisation, excision of the ranula alone and excision of the sublingual gland combined with the ranula
resulted in recurrence rates of 66.67%, 57.69% and 1.20% respectively.
Some authors advocate the injection of methylene blue into the ranula at the start of the procedure to improve the
preservation of vital surrounding structures.  Care must be taken as the dye can leak into (non-
ranula) surrounding
tissue and be misleading to the surgeon.


Complications

Ranula surgical treatment involves the following risks:

  • recurrence of the ranula (especially when the sublingual gland was not removed).
  • damage to the lingual nerve resulting in paræsthesia (numbness) of the nerve (up to 25% in some studies).  
    The tongue numbness generally resolves over the course of six months.
  • injury to the Wharton duct with the possibility of obstructive sialadenitis and ductal laceration leading to salivary
    leakage.
  • severe hæmorrhage from the lingual and sublingual vasculature
  • post-operative hæmatoma
  • partial dehiscence of the wound
  • post-operative infection


Baurmash recommended that ranulæ be treated initially by marsupialisation with packing and, if recurrence
occurs, the offending
sublingual gland should then be excised.

The essential treatment of a
ranula was meticulous dissection of the thin wall of the cyst in continuity with the
sublingual gland
of origin.  They used a technique of fibrin glue injection into the cystic space of the ranula after it
had been evacuated by aspiration.  The
fibrin glue within the cystic cavity prevents collapse of the wall of the cyst
during surgery and facilitates and simplifies the surgical procedure by clearly outlining the involved area and by
sharply delineating its thin wall.


Outcome and Prognosis

The overall risk for recurrence when the sublingual gland is not excised has been reported to be in excess of 50%.  
This rate drops to as low as 2% if the gland is excised.  As the risk to adjacent structures is higher for gland-
excising procedures, a trial of less-invasive procedures is advocated by some.

Smaller
cysts (< 1.5 cm) are usually more superficial in nature and may respond more readily to marsupialisation.  
Larger
cysts are more closely associated with the gland and usually require gland excision in association with cyst
removal.



Useful Articles:

Eur J Plast Surg 2002 - OK-432 injection therapy for plunging ranula

Lasers in Medical Science 2004.  Surgical Treatment of ranula with carbon dioxide radiation

J Oral Maxillofac Surg 2005 - Complications Associated with Surgical Management of Ranulas

Am J Neuroradiol 2006.  OK-432 Sclerotherapy of Plunging Ranula in 21 Patients - It Can Be A Substitute for
Surgery?

J Oral Maxillofac Surg 2007.  Clinical Controversies in Oral & Maxillofacial Surgery.  Part 1.  Management of the
Ranula

J Oral Maxillofac Surg 2008.  Conservative Treatment of Oral Ranula by Excision With Minimal Excision of the
Sublingual Gland

The Laryngoscope 2009.  Transoral Approach for Plunging Ranula — 10-Year Experience

New England J Medicine 2012.  Images in Clinical Medicine.  Ranula


Useful Websites:

Emedicine (ENT)

Emedicine (Dermatology)
Last Updated 17th October 2013