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