Management of a prestyloid parapharyngeal first branchial cleft cyst from puncture to surgical excision and how a routine procedure can turn into an emergency

Abstract

The anatomy of the parapharyngeal space (PPS) is complex and the differential diagnosis of tumours in this area broad. Although primary tumours of the PPS account for only 0.5% of head and neck neoplasms and are benign lesions in 80% of the cases, the surgical management is crucial and needs specific planning and evaluation of CT and/or MRI scans. In literature, there are several ways to surgically deal with PPS tumours and due to location and differentiation, can reach from transparotid, submandibular transcervical and transoral approaches, extending in a mandibulotomy, further radiotherapy. Parapharyngeal cleft cysts are extremely rare and their management can be complex. We describe the presentation, the diagnosis and further management of a 71-year-old woman with a 6 cm first branchial cleft cyst in the PPS from puncture over emergency tracheostomy to elective excision via a combined transcervical/transparotid and transoral approach. We highlight the importance of the differential diagnosis and the and the correct clinical management of this rare entity.

Background

Parapharyngeal space (PPS) tumours can be divided after their location and their entity. The PPS is an inverted pyramid-like region from the base of the skull, reaching the cornu of the hyoid bone. The borders are defined cranially by the temporal bone, the vertebrae and the prevertebral muscles posteriorly, the buccopharyngeal fascia medially and laterally by the mandible and the medial pterygoid muscle.^{1 2} The PPS can be divided into a prestyloid and retrostyloid or anterolateral and posteromedial space.^{2 3} The prestyloid space consists of fat, the deep lobe of the parotid and small salivary glands. The retrostyloid compartment is composed of the internal carotid, the internal jugular vein, the cranial nerves IX, X, XI and XII, lymph nodes and the glomus tissue. Most tumours of the PPS are represented by salivary gland tumours (40%–50%) and neurogenic tumours (17%–25%). Third, the paragangliomas make 10%–15% of all PPS tumours. Other entities combined account for 10%–33% of tumours in this anatomical region. Mentioned should be abscesses, necrotic lymph nodes, haemangiomas, lymphangiomas, aneurysms, angiosarcomas, rhabdomyomas, chordomas, meningiomas, osteomas and finally branchiogenic cysts.^3–5

During the embryological development, in the fourth week of gestation, six pairs of arches, clefts and pouches form the branchial or pharyngeal apparatus. Every arch consists of a cartilaginous element, muscular component, a corresponding branch of the aortic arch and a cranial nerve. These components later form various structures in the head and neck and due to non-fusion or subinvolution can result in branchial cleft cysts.^{6 7} These defects can present as fistulas, sinuses or cysts. The branchial cleft cysts are categorised from first to fourth branchial cleft cysts, depending on their embryogenic origin.⁶

First branchial cleft cysts make out about 7% of all branchial cleft cysts.⁶ Anomalies in the first branchial cleft can be classified by Work, into type I and type II malformations. Work type I malformations contain ectoderm only and typically present laterally to the facial nerve. Work type II cysts contain both ectoderm and mesoderm, are more common and classically present at the angle of the mandible.^{7 8} Overall, the occurrence of a branchiogenic cyst in the PPS is a very rare entity.

Case presentation

A 71-year-old woman presented in our ENT department, directly after consulting her ENT in practice with a chief complaint of a persisting dysphagia for 9 to 10 weeks and acute otalgia and otorrhea on the left side. She was unfebrile and complained a subjective progressive hearing loss over the last weeks, left-sided otorrhoea for 2 days, with no vertigo or tinnitus. She complained about a lockjaw and pain in the left joint of the jaw. She takes medicines against her hypothyroidism, rheumatism and high blood pressure and had a history of a colon carcinoma, which was treated operatively and with adjuvant chemotherapy two years ago. In her youth, she had a tonsillectomy.

Investigations

The ENT examination showed a trismus about 1.5 cm with a painful deviation of the jaw to the left and tenderness of palpation over the left temporomaxillary joint. The examination of the oral cavity and endoscopic transnasal inspection showed no malocclusion and a bulging of the left soft palate with a deviated uvula to the right and a protrusion of the nasopharyngeal wall, the tonsil and the caudal oropharyngeal wall on the left side. The auditive tube was compressed on the left side and the isthmus faucium was constrained from the left side near to the midline. Also, a perforated otitis media with clear secreting on the left side was shown. The puncture of the protruded soft palate set on an acute onset of swelling with a rapid progression of the swelling until a nearly full constraint of the isthmus faucium. Emergency CT scan showed a cystic lesion 6.4×4×4 cm in diameter reaching from skull base to the pterygopalatine fossa down to the submandibular gland and had contact with the parotid and the mandible. The radiological findings showed no malignancy criteria. Further, secrete retention of the left mastoid was shown (figures 1–3).

Figure 1.

Axial CT image revealing a cystic formation from left parapharyngeal skull base to the pterygopalatine fossa in contact with the parotid and the jaw.

Figure 2.

Axial CT scan showing left mastoid secret retention.

Figure 3.

Coronal CT scan depicting left big cystic lesion compressing the airway and reaching the skull base.

Treatment

In our case, first, the diagnosis was thought a peritonsillar abscess because this entity can present with trismus, swelling of the soft palate and a deviated uvula, furthermore ipsilateral otalgia. A peritonsillar abscess is an acute onset deep neck infection mostly seen in young adults.⁹ This pathology, as it is a complication of acute tonsillitis, can be managed in an inpatient setting through drainage and incision of the abscess and intravenous antibiotic treatment.

The puncture of the cranial part of the soft palate, which is routinely done in a peritonsillar abscess, led to a submucosal leakage and a soft-tissue protrusion with compression of the isthmus faucium, which resulted in an emergency tracheostomy.

Afterwards, the CT scan had shown a cystic lesion in the parapharyngeal space with no malignancy criteria, the differential diagnosis changed. Considerable diagnosis in PPS cysts are branchial cleft cysts; further differential diagnosis is lymphadenopathy, haemangioma, cystic hygroma, salivary gland tumour, cat scratch disease, atypical mycobacterial infection and cystic squamous cell carcinoma.^{7 10}

On presentation, the protruded soft palate on the left side was punctured by needle aspiration; we aspirated about 10 mL of a brown serous liquid. Directly after this aspiration, swelling of the soft palate was progressing and shifted over the midline of the isthmus faucium. We set up an instant CT scan of the neck to rule out an iatrogenic vascular injury and shifted the patient to the intensive care unit to secure the airway which got compromised rapidly. The anaesthesiologists performed nasal intubation; afterwards, we conducted cartilage-conserving tracheostomy,¹¹ submandibular cyst incision and a Penrose drainage insertion. Intravenous antibiotic treatment with 3×3 g ampicillin/sulbactam was started. The swelling of the soft palate was persisting on the following day, so we had to perform a transcervical incision of the cyst and an insertion of a parapharyngeal drainage over a left submandibular approach. Two days after the presentation, we extubated, and the clinical stabile patient was transferred to our periphery inpatient. Overall, the regression of swelling of the soft palate gave little satisfaction, that is why we had to operate again 5 days after presentation and conducted a transoral incision of the left oropharynx and insertion of a new Penrose drainage from intraoral to extracervical. This operation brought sufficient regression of the swelling, the trismus improved a little, the otalgia stopped and the airway no longer was in danger.

Ten days after the presentation, we were able to close the tracheostomy in local anaesthesia after covering it for 3 days without any clinical complications. The patient has been discharged after 14 days of inpatient care with intravenous antibiotics over 7 days. The histopathology of the needle aspiration showed parts of a branchial cyst with no malignancy.

Two months after presentation, the cyst had refilled to the size and volume of the first presentation; we performed an EMG neuromonitoring–supported left side total parotidectomy and resection of the cyst via a combined transcervical/transparotid and transoral approach without any complications. During the operation, we first positioned the invasive four-canal nerve monitoring of the facial nerve, reclined and rotated the head to the right. The skin incision was made preauricular to retromandibular and submandibular. The parotid was prepared and first, we performed a lateral parotidectomy and a neurolysis of the facial nerve. The cyst medial to the mandible was gradually separated from the bone and the medial parapharyngeal fibrotic links were dissected. As the cyst had contact with the deep layer of the parotid, we also had to resect the deep layer of the gland. Moreover, we set in a mouth gag and divided the fibrotic tissue through the soft palate. Finally, we dissected the cyst and removed it in toto with the deep layer of the parotid. The facial nerve was uncompromised and showed no lack of function postoperatively. The final histopathology showed no malignancy, further could not differentiate between a branchial cyst and an intracystic parotid adenoma or an intraductal parotid papilloma.

Outcome and follow-up

After surgical excision, the patient was discharged regardless of any functional impairment with an excellent cosmetic result.

Discussion

Our patient presented with trismus and an intraoral mass. Due to literature, most patients with a PPS lesion present with an intraoral mass (46%) or a cervical mass (52%).¹² The primary differential diagnosis, which turned out to be wrong, given the duration of the symptoms which the patient complained of, was a peritonsillar abscess. Peritonsillar abscesses are acute onset swelling and pain in the peritonsillar region and the soft palate.⁹

In our case, histology showed a branchial cyst, not surely distinguishable from or combined with an intraductal adenoma of the parotid. The PPS is a complex anatomical region where different neoplasms can rise. Most tumours in this region are benign.^12–14 In the PPS, tumours are benign in 80%–82%; a variety of neoplasms can develop in this region. Most frequently, salivary gland tumours and neurogenic tumours are found in this anatomical region.^{15 16} Our cystic tumour was located in the prestyloid part of the PPS. Due to literature, most salivary gland tumours are located in the prestyloid space, whereas the neurogenic differentiated neoplasms are mostly found in the retrostyloid portion of the PPS.¹⁷

Depending on location and differentiation including benign salivary gland tumours, radiotherapy can be a safe and feasible alternative to surgery.^{13 18} Most PPS tumours are treated by surgery and therefore need preoperative planning by CT or MRI techniques, radiographic techniques are showing high accuracy.^{15 19–21} Given our case, a preoperative CT scan was done, and we refrained from conducting an MRI. In cystic lesions, preoperative planning is highly accurate on a CT-basis due to orientation and the preoperative planning of the surgical approach. Various surgical approaches are described and need strategic preoperative planning not to compromise cranial nerves or result in poor cosmetic outcome.²² The surgical approaches reach from transcervical, transcervical-transparotid, transcervical-transmandibular, endoscopic-assisted transoral to transnasal techniques, infratemporal, and further transoral robotic-assisted.^{17 23 24} The most frequently used approach is the transcervical, guaranteeing a high safety and producing good surgical results.^{12 24}

Given the size and the location of our PPS cyst, we had to combine a transcervical/transparotid and a transoral approach which resulted in a good cosmetic and functional outcome.

Learning points.

• The knowledge how patients are presenting with first branchial cleft cysts and their differential diagnosis.

• The acute and elective management of patients with a parapharyngeal space tumour.

• How a routine transoral puncture can turn into an emergency case and how to handle such a situation.

• The surgical approaches and alternative treatments of parapharyngeal space tumours.