Case of the Week # 503

Case of the Week # 503

Javier Cortejoso
 on 04/19/2023
 on Wednesday, April 19th, 2023
The images demonstrate the following findings:
• Image 1, Videos 1-2: sagittal section and 3D rendering model demonstrate a normal fetal profile. In the axial view, a well-defined solid tumor is visible in the posterior part of the oral cavity behind the tongue.
• Image 2, Videos 3-5 (follow up ultrasound after 2 weeks): the sagittal view of the fetal head shows a complex mass filling the oropharynx and oral cavity causing antero-inferior displacement of the tongue and a persistently open mouth. The mass is predominantly isoechoic to hyperechoic with some internal anechoic areas and small calcifications. Surface 3D rendering of the fetal face shows a well-defined tumor emerging from the mouth.

A fetal oral mass is an uncommon sonographic finding that may be detected either at the time of a detailed fetal anatomic survey or incidentally during a third-trimester fetal assessment. The nasopharynx is the embryonic connection between the neural axis, alimentary, and respiratory tracts, and thus is subject to a variety of congenital malformations. Prognosis is highly dependent on the underlying etiology with regard to the likelihood of breathing or feeding difficulties, the risk of malignant transformation, and recurrence in the neonatal period. Therefore, accurate diagnosis is essential for appropriate parental counselling regarding the neonatal prognosis and postnatal management. Delivery by ex utero intrapartum treatment (EXIT) may be required, with a pediatric head and neck surgeon present at the time of delivery. Recently, Cruz-Martinez et al have described the use of fetal endoscopic tracheal intubation prior to delivery in a case of congenital cervical teratoma.

Imaging the fetal face is one of the most widely recognized uses of three-dimensional ultrasonography. Historically, 3D sonographic evaluation of fetal oral masses have been limited to the surface-rendering mode, but various 3D imaging techniques can be useful in the evaluation of fetal oral tumours. Furthermore, magnetic resonance imaging is useful in identifying lesions with intracranial extension, which have a particularly poor prognosis.

Teratomas are tumors composed of all three germ cell layers that develop along the midline of the body from the coccyx to the pineal gland. They represent 25–35% of all neonatal tumors. Teratomas of the head and neck represent approximately 6–10% of all teratomas and are most often found in the cervical region, followed by the nasopharynx and oropharynx. Oropharyngeal teratomas arise from the soft or hard palate in the region of the Rathke’s pouch or from the nasopharynx at the base of the sphenoid bone, sinuses, tonsil, tongue, or mandible.

Epignathus is an oropharyngeal teratoma located in the oral cavity that arises from the base of the skull. It has an incidence of 1 in 35,000 to 1 in 200,000 live births and occurs more frequently in females than males, with a ratio of 3:1. It has been rarely associated with sporadic chromosomal changes, though this is not typical. The hypothesis is that the epignathus is derived from unregulated growth of pluripotent cells in Rathke’s pouch. Most of these tumors are benign, though malignant transformation has been rarely described. The sonographic findings of epignathus include a heterogeneous mass with or without calcifications originating in the oropharynx and potentially extending out of the mouth. Most of these teratomas are unidirectional, but cases with intracranial extension causing destruction of brain tissue have been described. Doppler flow study may demonstrate high-volume and high-velocity flow inside the mass. In some cases, the presence of an epignathus is associated with other malformations including cleft palate, abnormal mandibular structure, bifid tongue or nose and duplication of the pituitary gland. It may be accompanied by elevated maternal serum alfa-fetoprotein, as the tumour is AFP-secreting. Associated findings include polyhydramnios, due to the inability of the fetus to swallow amniotic fluid, high-output cardiac failure and fetal demise due to circulatory obstruction. There are reports of the diagnosis being made after an apparently normal ultrasound scan at 16–17 weeks, which indicates the possibility that an epignathus may develop later in pregnancy.

Congenital epulis is a rare, benign, soft tissue lesion of the oral cavity that is exclusive to the newborn. It is also known as a congenital gingival granular cell tumor, congenital myoblastoma or Neumann tumor. It typically affects females more frequently than males (8:1), and presents as a pedunculated mass on the maxillary or, more commonly, on the mandibular alveolus (ratio 1:2). Ten percent of patients have multiple tumors. In 1871, Neumann first introduced the term congenital “epulis” to describe an unusual maxillary tumor in a newborn. “Epulis” is derived from the Greek word meaning “on the gum” or “gum boil”. Ultrasound reveals a well-defined, round, hypoechoic mass protruding from the mouth and with a branching pattern of feeder vessels. The branching vessel in the epulis is in contrast to the disorganized vascularization with high flow seen in oral hemangioma. Since epulis originates from the alveolar edge of the mouth cavity, the risk of airway obstruction is low and an EXIT procedure is generally not required.

Hamartoma is a focal disorganized overgrowth of mature tissues that have an identical cellular composition to the tissue normally located in that region. Congenital oral hamartomas are extremely rare, presenting clinically as an epulis. They are soft tissue masses that are solitary and pedunculated, with a good blood supply through a vascular pedicle.

Alternatively, findings in the oral cavity may be a vascular anomaly: (1) hemangiomas and (2) vascular malformations. Infantile hemangiomas are the most common tumors of infancy, with 65% involving the head and neck. Hemangiomas are a benign proliferation of endothelial cells common in the head and neck and relatively rare in the oral cavity. The most frequent location for oral hemangiomas is the lip. They appear as a solid mass with disorganized vascularization and high-flow vessels on ultrasound examination. Vascular malformations may be subdivided into high- or fast-flow lesions (contain arterial components and include arteriovenous malformations or fistulas), and slow- or low-flow ones (venous and lymphatic malformations).

The differential diagnosis of a mass in the fetal or neonatal oral cavity should include solid masses (epignathus or oropharyngeal teratoma, epulis, hamartoma, hemangioma, fibroma, leiomyoma, sarcoma, rhabdomyoma and rhabdomyosarcoma, lipoma, schwannoma, etc.) or cystic masses (lymphangioma, ranula, thyroglossal duct cyst, branchial cleft cyst, dermoid cyst, foregut duplication cyst, and anterior encephalocele). Prenatal imaging modalities are helpful in narrowing the differential diagnosis. The location of the mass may be helpful in narrowing the differential diagnosis further, as masses originating in the base of the skull and extending to the brain are likely to be aggressive teratomas.

Suggested reading:
• Allen LM. Prenatal 3-dimensional imaging techniques in the sonographic evaluation of an oral mass: comparison with postnatal imaging modalities. J Ultrasound Med 2011; 30: 561-568
• Bornstein E, Boozarjomehri F, Monteagudo A, et al. Diagnostic and prognostic aspects in the sonographic evaluation of a fetus with an oral mass. J Ultrasound Med 2009; 28: 689-693
• Calda P, Novotná M, Cutka D, et al. A case of an epignathus with intracranial extension appearing as a persistently open mouth at 16 weeks and subsequently diagnosed at 20 weeks of gestation. J Clin Ultrasound 2011; 39: 164-168
• Chung JH, Farinelli CK, Porto M, Major CA. Fetal epignathus: the case of an early EXIT (ex utero intrapartum treatment). Obstet Gynecol 2012; 119: 466-470
• Clement K, Chamberlain P, Boyd P, et al. Prenatal diagnosis of an epignathus: a case report and review of the literature. Ultrasound Obstet Gynecol 2001; 18: 178-181
• Coombs PR, Gilbertson T, Teoh M. Prenatal sonographic diagnosis of a congenital oral fibrovascular hamartoma. Ultrasound Obstet Gynecol 2011; 37: 736-738
• Cruz-Martinez R, Moreno-Alvarez O, Garcia M, et al. Fetal endoscopic tracheal intubation: a new fetoscopic procedure to ensure extrauterine tracheal permeability in a case with congenital cervical teratoma. Fetal Diagn Ther 2015; 38: 154-158
• Deloison B, Socolov D, Hornoy P, et al. Atypical case of prenatal cystic epignathus teratoma. Ultrasound Obstet Gynecol 2014; 44: 495-496
• Ekici E, Soysal M, Kara S, et al. Prenatal diagnosis of epignathus causing acute polyhydramnios. Acta Obstet Gynecol Scand 1996; 75: 498-501
• Lulla C, Hegde A, Thakur P. Antenatal 3-dimensional sonographic diagnosis of fetal oropharyngeal teratoma. J Clin Ultrasound 2008; 36: 305-307
• 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 2004; 183: 493-496
• Sarioglu N, Wegner RD, Gasiorek-Wiens A, et al. Epignathus: always a simple teratoma? Report of an exceptional case with two additional fetiforme bodies. Ultrasound Obstet Gynecol 2003; 21: 397-403
• Sweeney K, Spurway J, Mein B, et al. Congenital Epulis: a clinical case presentation. Australas J Ultrasound Med 2014; 17: 85-88

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