An unusual clinical presentation of a plunging ranula-The plunging ranula with extension to the vallecula.

KEY CLINICAL MESSAGE: A plunging ranula may present initially as an extensive vallecular cyst and correct diagnosis may be reached with the use of ultrasound, fluid aspiration for amylase detection, and MRI imaging.

ABSTRACT: The ranula is a pseudocyst of the sublingual salivary gland and can be divided into two known subtypes. The simple ranula and plunging ranula. While the simple type can be found in the floor of the mouth, the plunging ranula usually pervades the mylohoid muscle and presents as a cervical swelling. The presented case should outline the difficulties in diagnostic and treatment of an uncommon expression of a mucocele above the mylohoid muscle without presenting either a cervical or an intraoral swelling, only extending towards the vallecula. We present a previously unreported clinical manifestation of a ranula of an 18-year old male, which extends posteriorly, remaining confined in the supramylohyoid muscle space. The cystic lesion protrudes in the oropharynx, and clinically appears as an extensive vallecular cyst. On magnetic resonance imaging the initial suspected diagnosis of a vallecular cyst was changed to the final diagnosis of a plunging ranula. The marsupialization of the cyst sac was performed. Outpatient follow-up revealed a persisting ostium, indicating a continuous extravasation of the sublingual gland. The present case report describes an unusual clinical presentation of a plunging ranula, remaining above the mylohyoid muscle and protruding into the oropharynx, misdirecting to the first suspected diagnosis of a vallecular cyst. The case highlights the useful contribution of the MRI imaging for differential diagnoses and the need for criteria to indicate further investigations.