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A Mass in the Infratemporal Fossa

Educational Objective
Based on this clinical scenario and the accompanying image, understand how to arrive at a correct diagnosis.
1 Credit CME

A 51-year-old woman was referred for evaluation of headache, right-side jaw pain, paresthesia, and trismus. The patient reported that the facial and jaw symptoms had evolved gradually over the past 5 years and that multiple medical therapies had provided only minimal relief of pain. The patient’s medical history included anxiety, depression, emphysema, hyperlipidemia, migraines, and pseudoseizures. She denied prior head trauma and had no pertinent surgical history. On physical examination, the patient had normal body habitus and reported bilateral tenderness of the temporomandibular joints and paresthesia of the right trigeminal nerve in the V2 and V3 distribution with intact masseteric nerve and symmetric facial nerve. Audiometric evaluation showed normal hearing bilaterally. Magnetic resonance imaging (MRI) revealed a cystic mass in the right side of infratemporal fossa (ITF) that was nonenhancing on T1 sequencing with contrast and hyperintense on T2 (Figure 1A).

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A. Encephalocele

The ITF is a difficult-to-access space between the skull base, lateral pharyngeal wall, and ramus of the mandible. It is bounded anteriorly by the posterolateral wall of the maxillary sinus; posteriorly, by the carotid sheath; laterally, by the ramus of the mandible; medially, by the lateral pterygoid plate, tensor veli palatini, and levator veli palatini; superiorly, by the greater wing of the sphenoid; and inferiorly, by the medial pterygoid muscle. The medial border of the infratemporal fossa is continuous with the pterygopalatine fossa.1

The differential diagnosis of an ITF mass typically includes various tumors, such as juvenile nasopharyngeal angiofibroma, parotid tumors, and schwannoma.2 In rare cases, encephaloceles can present in the ITF. Diagnosis of ITF lesions can often be delayed because symptoms are vague, and there are few examination findings that suggest this specific diagnosis.

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Article Information

Corresponding Author: James G. Naples, MD, Division of Otolaryngology–Head & Neck Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 (jnaples513@gmail.com).

Published Online: March 31, 2022. doi:10.1001/jamaoto.2022.0175

Conflict of Interest Disclosures: Dr Naples reported receiving honorarium from DeckerMed for serving as editor-in-chief, outside the submitted work. No other disclosures were reported.

Additional Contributions: We thank the patient for granting permission to publish this information.

References
1.
Casale  J , Bordoni  B . Anatomy, head and neck, infratemporal fossa. In:  StatPearls. StatPearls; 2022.
2.
Lisan  Q , Leclerc  N , Kania  R , Guichard  JP , Herman  P , Verillaud  B .  Infratemporal fossa tumors: when to suspect a malignant tumor? a retrospective cohort study of 62 cases.   Eur Ann Otorhinolaryngol Head Neck Dis. 2018;135(5):311-314. doi:10.1016/j.anorl.2018.06.005PubMedGoogle ScholarCrossref
3.
Kato  H , Kanematsu  M , Mizuta  K ,  et al.  “Flow-void” sign at MR imaging: a rare finding of extracranial head and neck schwannomas.   J Magn Reson Imaging. 2010;31(3):703-705. doi:10.1002/jmri.22071PubMedGoogle ScholarCrossref
4.
Matos Cruz  AJ , De Jesus  O . Encephalocele. In:  StatPearls. StatPearls; 2021.
5.
Alobaid  A , Schaeffer  T , Virojanapa  J , Dehdashti  AR .  Rare cause of trigeminal neuralgia: Meckel’s cave meningocele.   Acta Neurochir (Wien). 2015;157(7):1183-1186. doi:10.1007/s00701-015-2434-4PubMedGoogle ScholarCrossref
6.
Gozgec  E , Ogul  H .  Giant cephalocele case mimicking cystic neoplasia in skull base.   J Craniofac Surg. 2020;31(6):e530-e532. doi:10.1097/SCS.0000000000006460PubMedGoogle ScholarCrossref
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