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Neuroradiology Case of the Week

Case 353

October 2008

Daniel Ginat, MD, MS, John P. Deveikis, MD
and P-L Westesson, MD, PhD, DDS

Clinical Presentation: Patient is a newborn term infant with a visible soft palate mass and respiratory stridor.

Imaging Findings:
Neck CT Findings: A large, multiloculated mass with peripheral enhancement and a non-enhancing central cystic area occupies the oropharynx and right side of the soft palate (Fig. 1). The mass appears to contain calcifications (Fig. 2). The mass is somewhat ill-defined and causes displacement of the endotracheal tube towards the left. The right parapharyngeal space also appears displaced posteriorly, but does not appear to be involved.
Face and Neck MRI Findings: Cystic and calcified mass lesion in the region of the soft palate involves the pharyngeal mucosal space and right parapharyngeal region, causing focal upper airway narrowing. This lesion is of heterogeneous signal intensity: bright on T2 and hypointense on T1 with mild enhancement. Areas of linear flow void appearing are also seen within this lesion on T2-weighted images. This lesion is separate from the parotid gland. There is no significant neck lymphadenopathy in the visualized portions of the neck.

Diagnosis: Oropharyngeal teratoma

Discussion: Teratomas are neoplasms derived from all three germ cell layers from multipotential germ cells. While teratomas represent 25-35% of all neonatal tumors, only about 6 to 10% of teratomas occur in the head and neck region [1]. Most of the head and neck teratomas affect the cervical region (1.5 to 3% of all teratomas) [2 & 3]. Oropharyngeal teratomas are exceedingly rare congenital tumors, occurring in 1 out of 35,000 to 200,000 individuals [1].
     Although typically benign, oropharyngeal teratomas are associated a high mortality rate with neonatal respiratory distress [2]. These tumors may be evident on fetal ultrasound and typically reveal heterogeneously enhancing lesions, containing cystic and solid areas. There may be associated polyhydramnios. Similarly, neonatal CT will reveal an obstructive mass of heterogeneous density containing calcifications and cystic areas. Calcifications are detected on CT in 16% of teratomas [1]. Often, there is neck hyperextension. The differential diagnosis of oropharyngeal teratomas includes lymphangioma, hemangioma, frontonasal meningoencephalocele, craniopharyngioma, glioma, angiofibroma, rhabdomyoma, rhabdomyosarcoma, and lymphoma [4].
     Fetal ultrasound and MRI are the preferred modalities for planning airway management, due to the paucity of ionizing radiation exposure. However, CT is indicated for pre-operative evaluation of oropharyngeal teratoma resection in neonates. In particular, CT enables assessment of bone involvement by the tumor [1].

References:

1. Morof D, Levine D, Grable I, Barnewolt C, Estroff J, Fishman S, Rahbar R, Jennings RW. 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. [PubMed]
2. Hasiotou M, Vakaki M, Pitsoulakis G, Zarifi M, Sammouti H, Konstadinidou CV, Koudoumnakis E. Congenital cervical teratomas. Int J Pediatr Otorhinolaryngol. 2004 Sep;68(9):1133-9. [PubMed]
3. Sayan A, Karaçay S, Bayol U, Arikan A. Management of a rare cause of neonatal airway obstruction: cervical teratoma. J Perinat Med. 2007;35(3):255-6. [PubMed]
4. Jarrahy R, Cha ST, Mathiasen RA, Shahinian HK. Congenital teratoma of the oropharyngeal cavity with intracranial extension: case report and literature review. J Craniofac Surg. 2000 Mar;11(2):106-12. [PubMed]