TMJ Condylar Pain From Parapharyngeal Space Tumor
Parapharyngeal space (PPS) tumor is a possibility when a patient presents with what on the surface may seem to be a common disorder well known to most clinicians—i.e., a painful temporomandibular joint refractory to care. Painful PPS masses are usually two centimeters or more in size before discovery is made, so prompt and accurate assessment, imaging, and treatment is essential. Though the literature says that PPS tumors are rare or uncommon, this is the second case we have seen in two years. We believe it is possible that discovery is sometimes impeded by the difficulty of the anatomical location—with the possibility of death occurring in some cases before the opportunity of discovery is realized.
The parapharyngeal space (PPS) is located in a complex, rather inaccessible region of the head and neck, lateral to the upper pharynx. The space is an inverted pyramid with the base of the pyramidal space at the base of the skull near the temporal and sphenoid bones. The lateral boundary includes the ramus of the mandible, including the mandibular condyle and coronoid process, and the medial pterygoid muscle and the deep lobe of the parotid gland. The medial boundary is the superior pharyngeal constrictor muscle, while the anterior boundary is the pterygomandibular raphe, pterygoid fascia, and the apex of the pyramid is at the greater cornu (horn) of the hyoid bone. The posterior boundary is formed by the ventral surface of the vertebrae and the prevertebral muscles.
The parapharyngeal space is divided into an anterior compartment, also known as a prestyloid compartment, and posterior or poststyloid compartment. The partition of the two compartments is comprised of the styloid process fascia and the fascia of the tensor levi palatini muscle. Most masses or lesions that occur in the prestyloid compartment are salivary gland tissue in origin, whereas tumors or lesions that occur in the poststyloid compartment are neurogenic or vascular in origin. The poststyloid structures also include the internal carotid artery, internal jugular vein, cranial nerves IX-thru XII, and the sympathetic chain and lymph nodes. The afferent drainage to the lymph nodes makes tumor spread problematic. Most cranial nerve deficits involve the vagus cranial nerve. The PPS space usually does not give visual evidence of tumors or masses since the boundary structures—with the prominent exception of the medial boundary and the inferior or apex boundary—are not distensible. A medial boundary mass would cause an oropharyngeal distention, and an apex or inferior boundary mass distention is noted in the lateral neck below the inferior margin of the mandible and near the hyoid bone greater cornu.
PPS tumors are estimated at 1 % of all head and neck tumors. Masses are equally distributed in the prestyloid and poststyloid compartments, with benign tumors comprising about 80% and cancerous masses about 20%. Most benign PPS lesions are painless but the cancerous lesions are usually painful. Table 1 presents possible complications of tumors in the PPS.
A 28-year-old male caucasian patient presented with intense, progressive sharp pain at the region of the TMJ condyle. He had no prior history of trauma or evidence of historical or current temporomandibulr joint internal derangement, and no familial history of cancer. This patient initially had only right-side condylar pain and MRI imaging was the method of tumor discovery. The pathology service described the tumor cells as essentially an undifferentiated carcinoma.
The patient underwent two surgeries, the first being a right side partial parotidectomy, then followed with a pre-auricular incision approach and major excision of the mass though, as one might expect, the margins were not clean. The patient suffered some trigeminal nerve third division sensory deficit and facial nerve labial branch deficit from the operation, with some evidence of motor nerve recovery in that area. Lingual nerve deficit and Inferior alveolar nerve deficit occurred as well. Post-op pain 21 days post surgery may be associated with the auricularotemporal nerve (ATN). The patient has also undergone 6 weeks of daily radiation therapy.
The purpose of this article is to challenge the pain clinician to at least consider a parapharyngeal space (PPS) tumor as a possibility when a patient presents with what on the surface may seem to painful temporomandibular joint refractory to care. Because of afferent drainage to the lymph nodes, tumor spread is a serious possibility. Masses are usually two centimeters or more in size before discovery is made, so prompt and accurate assessment, imaging, and treatment is essential.