Transoral Excision of a Huge Parapharyngeal Space Pleomorphic adenoma: A Possibility of Changing the Surgical Consideration to a Minimally Invasive Approach
A 35-year-old male presented to our casualty with a history of dysphagia and dysphonia beginning a couple of weeks previous. He was diagnosed as left-sided quinsy and was admitted for intravenous antibiotics and incision and drainage under local anaesthesia, but no pus collection was present. In the ward with proper history taking, the patient mentioned that he had a history of unilateral nasal obstruction for about five months followed by progressive left-sided hearing loss that resulted in a voice change. His wife mentioned that he recently started to snore and described symptoms of obstructive sleep apnea. On examination, the patient had a muffled voice. The oral cavity showed a huge left-sided mass displacing the uvula and tonsil that was occupying the left soft palate,oropharynx and hypopharynx (Figure 1).
Figure 3. MRI with contrast of the head and neck showing the huge mass coronally and axially.
The transoral approach in the excision of parapharyngal space (PPS) tumors (including pleomorphic adenomas, the most frequent tumor of the PPS),was first described by Goodwin & Chandler in 1988. It is cited by several series to be the second- most frequently adopted approach after a transcervical approach .Most others consider this approach the most controversial of all approaches to PPS tumors, therefore, it is relatively rarely used and is third in frequency (at 17%) after the transcervical approach (40%) and transparotid approach (19%) , or is last in frequency (at 2%), after the transcervical approach (63%), cervical-transparotid approach (25%), and transmandibular approach (8%) . Moreover, it is often considered to be even contraindicated because of its limited exposure, with consequent higher risk of complete tumor removal, tumor spillage, and possibility of neural injury or vascular injury (hemorrhage), dehiscence, fistulas and potential neck infection secondary to salivary contamination .
The transoral approach to a PPS tumor has been in the past classically limited to small and benign lesions because the surgical approach must guarantee a wide view of the surgical bed for a radical dissection of the tumor, with the lowest risk of injuries to vital structures. Thus, exclusively using this technique (no combination with external approaches) is recommended only in benign tumors < 3 cm, situated in the pre-styloid compartment of the PPS, and which are medially situated so as to be amenable to inspection/palpation in the oropharynx .
While it is probably true that the transcervical approach (combined or not with a transparotid route and/or mandibulectomy) increases the theoretical risk of damaging cranial nerves versus the transoral approach, this seems to only hold true for relatively small tumors. The risk level reverses between both approaches when dealing with large tumors.For the same reasons, the combined transoral-transcervical approach should also be avoided.
In our case report, we decided to remove the mass transorally despite its large size and we succeeded in doing so without the need for conversion to an external procedure. No complications occurred intraoperatively or postoperatively, which may occur with other open procedures.These complications can include hematoma,airway obstruction, infection, seroma,visible scars in young patients or face deformity after mandibulotomy and a long hospital stay . The challenge of a minimally invasive approach and the wish to minimize scarring for a young patient postoperatively were impetus for this approach by the surgical team.
According to my experience with this large tumor, my recommendation for the transoral approach is only when the tumor is located very medially, with the tumor size relatively not as important compared with a good mouth opening for exposure of the large tumor,exclusively in the location of the pre-styloid compartment of the PPS and not arising from the deep lobe of the parotid gland. There must be a well-confirmed separation between the tumor situated in the pre-styloid compartment and the internal carotid artery and internal jugular vein situated in the post-styloid compartment.
Our case report concludes by concurring with the opinion that, “A transoral approach for the surgical ablation of any benign PPS tumor of the pre-styloid compartment with certain prerequisites is yet to be established.”
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