Volume 32, Issue 1 , Pages 82-84, January 2011
The utility of fine needle aspiration to identify unusual pathology in a parapharyngeal mass
Article Outline
Abstract
The parapharyngeal space is a complex and well-defined anatomical zone lying lateral to the pharynx and medial to the ramus of the mandible. Although tumors of this space are rare, the parapharyngeal space is difficult to examine clinically; and diagnostic modalities of computerized tomographic scanning and magnetic resonance imaging are primarily used in the evaluation of parapharyngeal space lesions. We present a case report of a second branchial cleft sinus of the parapharyngeal space diagnosed with the assistance of fine needle aspiration (FNA), and we recommend FNA of parapharyngeal masses to provide definitive preoperative diagnoses.
1. Introduction
Tumors of the parapharyngeal space are rare, accounting for 0.5% of head and neck neoplasms [1]. 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 [2], [3], [4]. 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 [5], [6]. 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.
Fig. 1.
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.
Fig. 2.
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.
3. Discussion
Although the literature reports the value of CT and magnetic resonance imaging in the diagnosis of parapharyngeal space tumors and cysts [7], [8], [9], this case supports the role of diagnostic FNA of parapharyngeal masses. By imaging alone, the lesion was considered to be most consistent with a pathologically enlarged lymph node or a schwannoma. Conversely, Lanham and Wushensky [10] have reported a neck mass radiographically consistent with a branchial cleft cyst but histologically found to be a schwannoma. CT–guided FNA of the presented case revealed a benign lesion consistent with a branchial arch anomaly. Other studies have recognized the value of FNA cytology in the diagnosis of branchial cleft abnormalities, particularly those presenting as asymptomatic swellings [11], [12]. Khafif et al [4] advised preoperative FNA evaluation of all parapharyngeal space tumors.
FNA cytology findings in this case were strongly supportive of a branchial cleft cyst, including mature squamous cells, polymorphonuclear cells, and cholesterol crystals. Furthermore, a location in or adjacent to the parapharyngeal fat, as well as the communication with the tonsillar fossa, is highly suggestive of a second branchial cleft anomaly. Although most second branchial cleft anomalies are cysts along the anteromedial aspect of the sternocleidomastoid muscle, a second branchial fistula runs from the lateral neck to the tonsillar fossa; and cysts or sinuses can arise anywhere along this tract. The parapharyngeal space is the second most likely site for a second branchial cleft anomaly [13].
Whereas Daoud [14] discussed the missed diagnosis of branchial cysts in cervical lesions, this case demonstrates the importance of including branchial cleft anomalies in the differential of parapharyngeal masses in adults.
4. Conclusion
We present the case of a second branchial cleft sinus of the parapharyngeal space with CT findings that could be mistaken for benign or malignant neoplasms. Consequently, we recommend FNA biopsy of parapharyngeal masses for confirmation of pathology; and we recommend that physicians consider branchial cleft anomalies in the differential of parapharyngeal masses in adults.
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PII: S0196-0709(09)00215-4
doi:10.1016/j.amjoto.2009.09.009
© 2011 Elsevier Inc. All rights reserved.
Volume 32, Issue 1 , Pages 82-84, January 2011
