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2000-10-27-05 Answer to the case of the week #37 © Sleurs www.TheFetus.net

Answer to case #37

October 27 - November 10, 2000

Submitted by by Elke Sleurs, MD and Luc de Catte, MD 

Academic Hospital, Dept. of Obstetrics and Gynecology, Free University of Brussels, Brussels, Belgium

This fetus was scanned  in the late second trimester.  A 800kb video clip and The following images were obtained.

 

 

Findings:

The following structural defects were observed:

  • anterior mass,
  • emanating from the fetal mouth,  
  • partly cystic, partly solid
  • no calcifications

Case report:

This 32-year-old primigravida patient was referred at the ultrasound department at 19.5 weeks of gestation for a second opinion concerning a fetal facial mass. Scanning revealed a large, mixed tumor emanating from the pharynx and mouth. The fetal position did not allow for other congenital anomalies to be observed. The diagnosis of epignathus was made.  

An amniocentesis revealed an abnormal fetal karyotype. The chromosomal abnormality was also present in the tumor (mosaic Turner 45,X/46,X R(X) with a ring X-chromosome in 30% of the cells examined). Parental karyotypes were normal. The alpha-fetoprotein level in amniotic fluid was elevated (246.00 micrograms/ ml). 

Pathological examination confirmed an oropharyngeal teratoma originating from the sphenoid bone (epignathus) also protruding in the left nasal cavity. In addition there was an atrial and a ventricular septal defect, a hypoplastic left ventricle, stenosis of the aortic valve, mild cystic dysplasia of the left kidney and single umbilical artery.

Microscopic examination revealed a largely immature teratoma consisting of mainly neural tissue, cartilage and cysts lined with different types of epithelium.

Comment:

Epignathus (from the greek
epi = above and gnaqos = jaw) represents a rare congenital teratoma arising from the palate or pharynx in the region of the sphenoid (Rathke’s pouch)1,2. It may involve the sphenoid bone, pharynx, tongue and jaw. Although it may vary greatly in size and texture, epignathus generally extends through the mouth and creates an anterior facial mass. There is no known genetic or recurrence risk or predisposing factors. 

Most are diagnosed by ultrasound scanning in the late second and third trimesters, although early diagnosis at 151 and 17 weeks of gestation3 have been reported. A large mixed solid-cystic and sometimes calcified tumor projecting from the oral cavity suggests the diagnosis. Because the tumor can interfere with swallowing, polyhydramnios can be present3. Occasionally, a large and vascular epignathus may lead to high-output cardiac failure and subsequently to a non-immune hydrops fetalis.

Epignathus is mostly an isolated anomaly. Less than 10% of newborns with epignathus will have associated congenital malformations including cleft palate, hypertelorism, congenital heart anomalies, umbilical hernia and facial hemangiomas as well as Aicardi syndrome (agenesis of the corpus callosum, infantile spasms, and ocular anomalies)4 and Pierre Robin sequence5. Facial defects have been attributed to the mechanical effects of the teratoma on developing structures. Occasionally chromosomal malformations have been reported. (Yapar et al. (1995) (trisomy 13) and Abendstein et al. (1999) (inverted duplication of chromosome 1, conventional karyotyping was normal)6,7

The maternal serum alpha-fetoprotein level may be elevated. The amniotic fluid may contain acetylcholinesterase. 

The differential diagnosis of epignathus includes 

  • congenital epulis (congenital granular cell tumors of the gingiva or congenital myoblastoma), 
  • dermoids (hairy polyp), 
  • leiomyoma, 
  • hemangioma, 
  • thyroglossal duct cyst, 
  • cervical meningomyelocele, 
  • neuroectodermal tumor or 
  • brachial cleft cyst.

Most pharyngeal teratomas are histologically benign; they are classified as either mature or immature.

Management depends both on size and location. 

The maternal risks are mainly those related with polyhydramnios and represent 

  • respiratory compromise, 
  • preterm labor, 
  • premature rupture of the membranes and 
  • placental abruption. 

The neonatal prognosis depends on the size of the tumor and the degree of involvement of other structures. Severe respiratory compromise secondary to airway obstruction at the time of birth is the major neonatal risk. If tracheal occlusion is anticipated delivery should be by cesarean section as intubation or tracheostomy can be performed before clamping the umbilical cord8. Even with optimal management, survival rates are not higher than 30-40%. If diagnosis is made before 24 weeks gestation termination of pregnancy should be offered.

References:
1 Gull I et al: Antenatal sonographic diagnosis of epignathus at 15 weeks gestation. Ultrasound Obstet Gynecol 1999;13(4):271-3
2 Oliveira-Filho et al: Epignathus: report of a case with successful outcome. J Pediatr Surg 1998;33(3):520-1
3 Bruhwiler H et al: Ultrasound diagnosis of epignathus in the 17th week of pregnancy. Case report and review of the literature. Ultrashall Med 1995;16(5):238-40
4 Isaacs H, jr: Potter’s pathology of the fetus and the infant. Chapter 28: Tumors.
5 Vandenhaute B et al: Epignathus teratoma: report of three cases with a review of the literature. Cleft Palate Craniofac J 2000;37(1):83-91
6 Yapar EG et al: Sonographic diagnosis of epignathus (oral teratoma), prosencephaly, meromelia and oligohydramnios in a fetus with trisomy 13. Clin Dysmorphol 1995;4(3):266-71 
7 Abendstein B et al: Epignathus: prenatal diagnosis by sonography and magnetic resonance imaging. Ultrashall Med 1999;20(5):207-11
8 Levine AB et al: Contemporary management of a potentially lethal fetal anomaly: a successful perinatal approach to epignathus. Obstet Gynecol 1990:76(5):962-6

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