mucus extravasation cysts or mucoceles are an extremely common lesion of the minor salivary glands .
we report upon an unusual case of a submandibular gland mucocele presenting as a lateral neck swelling .
the term plunging or cervical ranula refers to mucoceles that extend below the mylohyoid muscle , beyond the sublingual space and invariably are associated with the sublingual salivary gland .
differentiation from submandibular gland mucoceles is potentially difficult , though plunging ranula is usually characterised by a so called  tail sign on imaging . in our case
a 54 year old woman presented with a large asymptomatic swelling of the right lateral neck .
the swelling had been present for three months but had attained large dimension and was still felt to be increasing in size .
she denied any history of trauma , surgery , infection , dysphagia , voice change or weight loss .
palpation of the neck mass revealed a soft , fluctuant , non - tender swelling approximately 6 cm in diameter arising superficially within the right submandibular region .
a magnetic resonance imaging ( mri ) scan revealed a large cystic structure in the right lateral neck involving the submandibular space ( fig 1 ) .
the sample proved inadequate for cytological assessment , however was found to have a raised amylase and protein content suggesting salivary origin .
mri scan showing cystic lesion within lateral neck under general anaesthesia the cystic mass was meticulously excised intact via a low submandibular incision .
it was found to be in continuity with the ipsilateral submandibular gland ( fig 2 ) .
histolopathology of the specimen confirmed a fibrous - walled retention cyst associated with a submandibular gland showing chronic obstructive changes .
the patient made an uneventful post - operative recovery with no evidence of recurrence at six months .
the presentation of a submandibular gland mucocele is uncommon with only a few reported cases in the literature ( 1 - 3 ) .
it has been postulated that this rarity might be due to the anatomical location of the gland and the protective nature of the mandible1 .
furthermore the physiology of the gland is such that unlike the sublingual gland , which exhibits continuous secretion , the submandibular gland secretes saliva only following stimulation ( 4 ) . nevertheless , despite the true aetiology being unknown
it is thought likely that trauma , obstruction and congenital anomalies are most likely causes ( 5 ) .
the differential diagnosis of a submandibular gland mucocele should include the numerous inflammatory , infective , developmental and neoplastic processes affecting the lateral neck .
in particular , a solitary cystic mass should be thoroughly investigated to exclude the possibility of cystic degeneration of a lymph node secondary to metastatic squamous cell carcinoma .
fine needle aspiration biopsy for cytological and biochemical assessment can confirm the nature of the cyst and is usually found to have a high amylase and protein content ( 6 ) .
the management of a submandibular gland mucocele is potentially controversial and includes a number of treatment modalities that have been advocated in the management of the cervical or plunging ranula .
injection of scelorosing agents have been used to induce inflammation and fibrosis from within the lumen of the cyst thus sealing further extravasation .
aspiration is a simple technique but yields a high recurrence rate and as such its use has been largely restricted to the conservative management in the paediatric population .
marsupialisation has gained popularity not least because of its relative simplicity , but also because it involves only limited dissection and therefore a reduced risk of damage to adjacent structures .
recurrence however is unpredictable leading some authors to advocate a modified technique incorporating packing the cyst cavity ( 2 ) .
contemporary opinion suggests that because mucoceles are pseudocysts there is no imperative to remove the cyst lining .
appropriate management should focus on identification and elimination of the salivary gland responsible for the source of mucus secretion ( 1 ) .
removal of the stimulus for secretion should cause involution of the cystic cavity , which seals itself , naturally ( 7 ) .
we would advocate that in cases of a submandibular gland mucocele the lesion should be excised via a cervical approach in conjunction with the submandibular gland .
if any doubt exists as to the close involvement of the sublingual gland then it would be advisable to remove this gland as well .
 mucus extravasation cysts or mucoceles are an extremely rare occurrence in the major salivary glands 
 . we report upon an unusual case of a submandibular gland mucocele presenting as a neck lump . 
 it should therefore be considered in the differential diagnosis of swellings in the lateral neck . 
 diagnosis and management are complicated by their similarity to the plunging or cervical ranula and differentiation may be potentially difficult . 
 detailed imaging often reveals the plunging ranula as being characterised by a so called  tail sign . in our case 
 this sign was absent and subsequent excision confirmed origin from the submandibular gland . 
 we discuss potential treatment modalities and propose a rationale for definitive management . 
INTRODUCTION
CASE REPORT
DISCUSSION