Introduction
Head and neck cancer patients often present with complex, multidisciplinary problems that span many specialties. Clinicians who only occasionally deal with head and neck cancer patients, or who are inexperienced, are unlikely to appreciate these subtleties, and are therefore likely to misdiagnose presentations.
We highlight a particular problem which arose when imaging a post-operative laryngectomy patient, in order to draw attention to the need for subspecialisation; this issue is relevant not only to ENT surgeons' subspecialisation as head and neck surgeons, but also to all members of the head and neck multidisciplinary team.
Clinical case
A 59-year-old man presented with a one-month history of worsening neck pain, neck swelling and leaking subcutaneous collections around his post-laryngectomy tracheal stoma.
Three months earlier, he had undergone a salvage laryngectomy, bilateral neck dissection and hemi-thyroidectomy.
Two years prior to this, the patient had been diagnosed with a tumour stage 1a, node stage 0, right glottic squamous cell carcinoma (SCC). He had been treated with laser excision, but had re-presented 12 months later with local recurrence at the anterior commissure extending to both anterior vocal folds. He had subsequently been treated with radiotherapy, with a total dose of 66 Gy in 33 fractions. A further local recurrence, 12 months later, had been treated with surgical salvage.
During the current re-presentation, examination revealed two subcutaneous collections peri-stomally, and significant bilateral neck swelling.
Computed tomography (CT) scanning with contrast was performed to exclude deep neck collections (Figure 1). A unilateral mass with high signal contrast uptake was found anterior to the left common carotid artery. This CT scan with contrast was initially interpreted by a junior radiologist as a pseudoaneurysm. However, a subsequent ultrasound of the left neck demonstrated a patent left common carotid artery and left internal jugular vein.
Axial computed tomography scan of a 59-year-old man with bilateral neck swelling post-laryngectomy.
Fluid aspirated from the subcutaneous collections was amylase-positive, indicating a pharyngo-cutaneous fistula; it also demonstrated malignant SCC.
Discussion
In this case, the important CT findings that were suggestive of pseudoaneurysm, and which can be seen in other patients with extensive neck surgery, included the positioning of the thyroid in relation to the internal carotid artery. Due to previous surgery, the remnant hemi-thyroid was in close proximity to the internal carotid artery. Another important feature was the distorted shape of the thyroid following surgery. A normal thyroid has a typical, distinct triangular shape; however, in our case the thyroid was round in appearance, consistent with a pseudoaneurysm. The intense contrast enhancement, seen in both pseudoaneurysms and thyroids, was another important distinguishing feature. A delayed contrast scan was not performed in our case – this would have distinguished between thyroid and pseudoaneurysm by demonstrating no retention of contrast in the case of a pseudoaneurysm, but retention of contrast in the case of a thyroid.
Given these features, our patient's CT scan findings, taken out of context by a radiologist inexperienced in head and neck surgery, could easily be misinterpreted as a pseudoaneurysm.
Pseudoaneurysms of the carotid artery are not common in our clinical practice as they are predominantly associated with cranial trauma. Typically, pseudoaneurysm formation occurs secondary to hyperextension and contralateral head rotation, which compresses the cervical internal carotid artery against the lateral mass of the second cervical vertebra, resulting in arterial dissection and pseudoaneurysm formation.Reference Cummings1 These lesions are typically treated endovascularly.Reference Nadig, Barnwell and Wax2 Clinically, pseudoaneurysms of the carotid artery can present with pain, swelling, a pulsatile thrill or audible bruit, and/or neurological deficits.
• Pseudoaneurysms are rare following head and neck surgery
• Post-laryngectomy, a misshapen remaining hemi-thyroid may easily be mistaken for a pseudoaneurysm
• Ultrasonography easily distinguishes a thyroid remnant from a pseudoaneurysm
• An experienced head and neck radiologist is vital for interpreting complex post-surgical radiology
There are several documented case reports of pseudoaneurysms associated with neck dissection and radiotherapy used in the management of head & neck cancer. There are three cases of pseudoaneurysms reported to have arisen following neck dissection, two involving the carotid bifurcationReference Iguchi, Takayama, Kusuki, Nakamura, Kanazawa and Hachiya3, Reference Girishkumar, Sivakumar, Andaz, Santosh, Solomon and Brown4 and one involving the common carotid artery.Reference Flor, Sardanelli, Ghilardi, Tentori, Franceschelli and Felisati5 Four cases are reported to have arisen following radiotherapy used as singular therapy, two involving the internal carotid artery,Reference Cheng, Lee, Chiang, Ho and Kuo6, Reference Chen, Lin, Jen, Juan, Hsueh and Lee7 one involving the common carotid arteryReference Chen, Lin, Jen, Juan, Hsueh and Lee7 and another involving the external carotid artery stump following ligation.Reference Maruyama, Arai, Hoshida, Yoneda, Furukawa and Yoshizaki8 Another two case reports have described pseudoaneurysm formation following both neck dissection and radiotherapy involving the common carotid arteryReference Tanaka, Kimura and Furukawa9 and the external carotid artery.Reference Minion, Lynch, Baxter and Lieberman10
Pseudoaneurysms are a rare delayed complication of head and neck cancer management. Despite this, it is important for head and neck surgeons and radiologists to consider the possibility of such a diagnosis, especially in patients presenting with neck swelling and pain following neck dissection or radiotherapy. It is also important to determine the patient's surgical and treatment history before interpreting their radiological images.
This common radiological misinterpretation of a remaining hemi-thyroid following total laryngectomy is a lesson that all ENT surgeons and radiologists should learn. Early recognition and correct diagnosis will not only save the surgeon considerable angst but will also prevent unnecessary additional investigations.
