Tennessee Women"s Care, Nashville TN
Synonyms: Retention cyst, mucocele, oral pseudocyst.
Definition: A congenital ranula is a cystic malformation seen in the oral cavity. A ranula usually results from the obstruction of the sublingual or minor salivary glands. Clinically a fluid-filled structure fills the mouth and is seen to elevate the tongue. These pseudocysts are normally located in the sub-lingual space between the mylohyoid muscle and the lingual mucosa.
Case report: Only three cases of antenatal detection of congenital ranula have been reported so far in the literature [Shipp, et al1 (1995); Fernandez, et al 2 (1998) and Onderoglu, et al3 (2003). The case reported below is the fourth case of prenatal detection of a ranula. Case of the week #123 - LÃvia Rios,MD
Prevalence: The incidence of a congenital ranula is estimated to be 0.74%2.
Etio-pathogenesis: A ranula is a fluid collection that occurs either due to:
1. Disruption of minor salivary ducts leading to extravasation of mucous structures into adjacent structure and resulting in a mucous extravasation cyst. These are more common in children and young adults and rarely occur in neonates. The ranula is not lined by an epithelium in this case.
2. A blocked duct causing proximal expansion and resulting in a mucous retention cyst, seen in neonates and the fluid collection is lined by salivary duct epithelium.
Types: Ranulas can be classified according to their site of location. They can be
* A simple ranula — located in the floor of the mouth,
* A cervical ranula — located in the paracervical region,
* And a plunging ranula — located near the upper airway and extending into the floor of the mouth. [plunging ranulas exhibit a so called -tail sign' on MRI].4
Sonographic findings: The antenatal scans would show:
* A hypoechoic cystic mass in the floor of the mouth, with no solid components.
* If very large, the mass may displace the tongue upwards.
* No vascularity can be seen within this cystic structure.
Implications for targeted examinations: Once an oral tumor is identified, it is necessary to rule out other associated anomalies. If no other abnormalities are noted, then adequate monitoring of the growth of the intra-oral mass must be done. If the mass becomes too large, it may interfere with the swallowing mechanism in the fetus, resulting in polyhydramnios. If it is a cystic mass, decompression may be carried out via percutaneous cyst aspiration.
Differential diagnosis: Oral tumors arising in a newborn are very rare. The following tumors must be considered:
1. Epulis8 — this is a rare, benign granular cell tumor which is solid. It arises from the alveolar ridge. Color and power Doppler usually demonstrates marked blood flow in the tumor. It is a self limiting lesion and responds to conservative excision.
2. Foregut duplication cyst10 - this rare enteric duplication cyst may occur in the floor of the mouth. It is cystic in nature and may closely mimic a ranula.
3. Epignathus11,12 — this is an oropharyngeal teratoma mostly arising from the palate. It appears as solid-cystic tumor with mixed areas of hypo and hyperechogenicity, may have calcifications and is found in association with polyhydramnios. It can cause significant morbidity and mortality.
4. Median palatal mucosal cyst [Epstein's pearl]13 - this is benign and self resolving.
5. Gingival cyst of the newborn [dental lamina cyst]13 — this is benign and self resolving.
6. Vascular hamartomas4,5 — these may be hemangiomas or lymphangiomas [cystic hygromas] and are usually located on the tongue. These tumors may appear as solid- cystic masses on ultrasound and require surgical excision.
7. Other tumors of the tongue include:4,5
* Thyroglossal duct cyst
* Lingual thyroid
* Dermoid cyst
* Granular cell myoblastoma and
* Heterotopic gastric mucosal cyst.
Complications: A ranula or any oral tumor if large enough can cause obstruction of the airway or feeding problems.
Prognosis: Excellent prognosis. Even if the tumor is large, an airway can be established via the EXIT procedure; and the tumor can be excised at a later stage.
Recurrence risk: If properly excised, a ranula does not recur.
Management: Ex-utero intrapartum treatment [EXIT procedure]15 can be used to obtain a fetal airway in cases of large obstructing masses that may potentially obstruct the airway and cause respiratory distress. This procedure involves establishing an airway before the feto-maternal circulation is interrupted.
The definitive treatment of a ranula is surgical,16 and according to a recent study by Haberal, et al either marsupialization or excision of the ranula may be performed with equally successful results. The commonest complication of surgery that they found was rupture of the ranula during the operation, which if occurred, appeared to cause no increased risk of recurrence.
References:
1. Shipp TD, Bromley B, Benacerraf B. The ultrasonographic appearance and outcome for fetuses with masses distorting the fetal face. J Ultrasound Med. 1995 Sep; 14(9):673-8.
2. Fernandez Moya JM, Cifuentes Sulzberger S, Diaz Recasens J, et al. Antenatal diagnosis and management of a ranula. Ultrasound Obstet Gynecol. 1998 Feb; 11(2):147-8.
3. Onderoglu L, Saygan-Karamursel B, Deren O, et al. Prenatal diagnosis of ranula at 21 weeks of gestation. Ultrasound Obstet Gynecol. 2003 Oct; 22(4):399-401.
4. Rousseau T, Couvreur S, et al. Prenatal diagnosis of enteric duplication cyst of the tongue. Prenat Diagn. 2004 Feb; 24(2):98-100.
5. Akyol MU, Orhan D. Lingual tumors in infants: a case report and review of the literature. Int J Pediatr Otorhinolaryngol. 2004 Jan; 68(1):111-5.
6. Jorgenson RJ, Shapiro SD, Salinas CF, Levin LS. Intraoral findings and anomalies in neonates. Pediatrics. 1982 May; 69(5):577-82.
7. Polak P, Santavy J, Micanik B, et al. An unusual tumor of the oral cavity in a fetus and prenatal ultrasonography--case report. Ceska Gynekol. 2002 May; 67(3):163-7.
8. Nakata M, Anno K, Matsumori LT, et al. Prenatal diagnosis of congenital epulis: a case report. Ultrasound Obstet Gynecol. 2002 Dec; 20(6):627-9.
9. Saheeb BD. Recurrent congenital bilateral ranula: a case report.
SADJ. 2001 Aug; 56(8):366-8.
10. Kong K, Walker P, Cassey J, O"Callaghan S. Foregut duplication cyst arising in the floor of mouth. Int J Pediatr Otorhinolaryngol. 2004 Jun; 68(6):827-30.
11. Morof D, Levine D, Grable I, et al. Oropharyngeal Teratoma: Prenatal Diagnosis and Assessment Using Sonography, MRI, and CT with Management by Ex Utero Intrapartum Treatment Procedure. AJR Am J Roentgenol. 2004 Aug; 183(2):493-6.
12. Gaucherand P, Rudigoz RC, Chappuis JP. Epignathus: clinical and sonographic observations of two cases.
Ultrasound Obstet Gynecol. 1994 May 1;4(3):241-4
13. Ikemura K, Kakinoki Y, Nishio K, Suenaga Y. Cysts of the oral mucosa in newborns: a clinical observation. J UOEH. 1983 Jun 1; 5(2):163-8.
14. Lalwani AK, Engel TL. Teratoma of the tongue: a case report and review of the literature. Int J Pediatr Otorhinolaryngol. 1992 Nov; 24(3):261-8.
15. Stevens GH, Schoot BC, Smets MJ, et al. The ex utero intrapartum treatment (EXIT) procedure in fetal neck masses: a case report and review of the literature. Eur J Obstet Gynecol Reprod Biol. 2002 Jan 10; 100(2):246-50.
16. Haberal I, Gocmen H, Samim E. Surgical management of pediatric ranula. Int J Pediatr Otorhinolaryngol. 2004 Feb; 68(2):161-3.