Parapharyngeal Space Tumors
Parapharyngeal space tumors are typically asymptomatic and patients become aware of them only when a bulge develops in the palate or sidewall of the throat near the tonsils. The vast majority of these tumors are benign. Oftentimes the diagnosis is made on the basis of a scan performed for other reasons and an asymptomatic mass is identified. The diagnosis and characterization of these tumors requires appropriate imaging studies such as MRI and a CT scan to understand the nature and the biology of the growths. The majority of these tumors are benign, most of them arising from the deep lobe of the parotid gland. Tumors may also arise from minor salivary glands as well as from the nerves in this region. There is a small group of tumors known as paraganglioma that may arise from one of a number of structures located in the neck, including the jugular vein, the vagus nerve and the carotid artery.
The primary treatment for these types of tumors is surgery. Often a biopsy is not required unless there are unusual features that raise concern about the possibility of a malignancy.
The size and biology of the tumor determines the best surgical approach. Careful analysis through appropriate imaging will often provide the critical awareness needed for the correct diagnosis of a parapharyngeal space tumor as well as the most likely type of tumor that is present. Interpretation of the scan will permit the surgeon to determine the best surgical approach for the safe and effective removal of the tumor. Due to the complexity of the anatomy of the parapharyngeal space, which contains the carotid artery and numerous cranial nerves, surgical planning is vital. A determination of the optimal approach to the parapharyngeal space, known as surgical access is most often performed through a standard parotid approach (an incision in front of the ear and extending underneath the lobule into the sulcus behind the ear) combined with an extension of the incision underneath the jawline toward the midline of the neck. Identification and protection of the facial nerve is a critical factor in the safe removal of these tumors to prevent facial nerve paralysis. In rare instances, surgical exposure may require cutting of the jawbone in the midline (median labial mandibulotomy). This more extensive surgical access may be necessary for larger tumors (greater than five centimeters), vascular tumors and malignancies. The execution of a median mandibulotomy approach requires an incision across the chin and lower lip. While these incisions heal very favorably to produce a barely noticeable scar, the thought of such an incision is usually very problematic for patients to accept.
There is an intermediate approach, referred to as a subcutaneous mandibulotomy, developed by Mark Urken, MD, and Daniel Buchbinder, DMD, MD, which eliminates the necessity of an incision through the chin and lower lip and still provides exposure for the safe removal of larger parapharyngeal space tumors.