1

Introduction

Tumors of the parapharyngeal space are rare, accounting for 0.5% of head and neck neoplasms . Most parapharyngeal lesions originate from salivary, neural, or lymphoid tissue. The extensive differential diagnosis of parapharyngeal masses also includes uncommon branchial origin lesions, chordomas, and inflammatory masses . The diagnostic evaluation of parapharyngeal space lesions relies mainly on radiographic imaging: contrast-enhanced computerized tomographic (CT) scanning and magnetic resonance imaging. The role of fine needle aspiration (FNA) in the routine diagnostic workup is controversial . We report a case of a rare second branchial cleft cyst of the parapharyngeal space that demonstrates the value of FNA in the diagnostic evaluation and management of patients with parapharyngeal space tumors.

2

Case report

A 52-year-old man was referred to our otorhinolaryngology outpatient clinic for a parapharyngeal mass incidentally noted on a CT myelogram of the cervical spine. The patient had experienced neck pain radiating to his upper extremities for several months after an accident and had imaging studies performed as part of the evaluation of his chronic neck pain. The patient endorsed occasional dysphagia to solids and recent weight loss attributed to opioid use. He denied odynophagia, and he was otherwise asymptomatic. On physical examination of the head and neck, a subtle submucosal mass was visible by mirror in the right nasopharynx; full examination of the head and neck, including cranial nerve evaluation, detected no further abnormalities. Flexible laryngoscopy confirmed submucosal fullness of the right nasopharynx.

On the CT myelogram, a 2.5-cm lesion in the right parapharyngeal fat was promptly noted by the radiologist performing the procedure; and the patient was brought back to the CT scanner for additional images with intravenous contrast. The follow-up scan revealed a hypodense, nonenhancing, well-circumscribed 2.5-cm mass in the right parapharyngeal space ( Fig. 1 ). The mass was anteromedial to the internal carotid artery, separating the artery from the longus capitus muscles. The parapharyngeal fat was displaced anterolaterally, suggesting the retropharyngeal space as the most likely site of origin. The preferred radiologic diagnoses were metastatic disease to a retropharyngeal node and a predominantly cystic schwannoma. To distinguish between these possibilities, CT-guided FNA of the mass was requested.

Computed tomographic scan of the neck performed after introduction of both myelographic and intravenous contrast reveals a nonenhancing 2.5-cm mass (m) anteromedial to the internal carotid artery (arrow), displacing the parapharyngeal fat (arrowheads) anterolaterally.

Using a transfacial approach, a 25-gauge spinal needle was advanced into the mass ( Fig. 2 ). Thick, white material was aspirated from the mass; so a 20-gauge needle was then used. Less than 1 mL of the viscous white material could be aspirated, even with the larger needle. In-procedure cytopathologic analysis revealed only acellular debris; so a 20-gauge spring-loaded biopsy needle was advanced into the mass via the same approach, and a core biopsy was obtained that included portions of the cyst wall. Final cytologic assessment of the biopsy sample was negative for malignant cells and revealed benign squamous cells, proteinaceous fluid, and cholesterol crystals indicating a likely branchial cleft anomaly.

Computed tomographic image obtained during percutaneous transfacial CT-guided biopsy. The biopsy needle (*) extends between the mandible and the maxilla into the hypodense mass (m). This approach avoids the internal carotid artery and the facial nerve.

The mass was excised via a transcervical approach. During dissection of the mass, it spontaneously emptied through direct communication to the right tonsillar fossa. The entire cyst was dissected out and removed. Deep soft tissue closure was achieved by approximating the posterior belly of the digastric muscle to the soft tissues medial to the mandible. The tonsillar mucosa was then closed via a transoropharynx approach, and the skin was closed in layers over a Jackson-Pratt drain. The final pathology revealed hyperplastic tonsillar-type tissue with acute cryptitis, extensive fibrosis, and tonsilliths.

The patient experienced a postoperation course free from complications other than the sore throat typical after instrumentation of the tonsillar fossa. After a blue dye swallow study did not reveal communication between the oropharynx and the drain site, the drain was removed; and the patient was discharged on postoperation day 1. He has had no evidence of recurrence on clinical follow-up.