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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 backpressure
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 visualize with ultrasound.

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
homotoxicological 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 reform and recur.

Packing the cyst cavity with gauze for 7 - 10 days
improves the success rate.  In one report, 11 of 12
patients had resolution of their
ranula with
marsupialisation and subsequent packing of the cavity.

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.

A tissue biopsy is recommended first to confirm the
diagnosis of
ranula.  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.
into the ranula at the start of the procedure to improve
the preservation of vital surrounding structures.  Care into
surrounding tissue.


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 oral 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.  Because 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.


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