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9 Articles in Volume 8, Issue #1
Spine-related Pain in Sports Medicine
Outpatient Interventional Treatments for Migraines and Pain Flare-ups
Identifying Abusers Prior to Initiating Chronic Opioid Therapy
Urine Drug Tests in a Private Chronic Pain Practice
Platelet Rich Plasma (PRP) Matrix Grafts
Role of Sustained-release Opioids in Treating Chronic Pain
Adenoid Cystic Carcinoma of the Parotid Gland
Evaluation and Management Codes Drive Medical Necessity
Grappling with the Ethics of Practical Pain Management

Adenoid Cystic Carcinoma of the Parotid Gland

A mimic of craniofacial pain symptoms of Ernest Syndrome and stylomandibular ligament injury, ACC in this case presented with ear, jaw and tooth pain, as well as pain on chewing and opening wide—all as a result of a growing mass affecting the trigeminal nerve with perineural invasion, the carotid artery, and the parotid gland.

The following information represents an eighteen-month ordeal for a patient who is thankful that he did not get lost in what can be a complex maze of diagnostic dead-ends. Fortunately, several doctors listened to the patient in the diagnostic process. The patient is grateful that their cooperative effort has, for the moment, solved his malignant pain problem, and possibly changed his outcome.

Craniofacial pain symptoms are often complex in nature and can represent a variety of unrelated conditions. Just a few from a long list include cardiac ischemia and acute myocardial infarction,1 Ernest Syndrome and temporal tendonitis,2-5 temporomandibular joint pain, and salivary gland adenoid cystic carcinoma (ACC).6 These diverse conditions can have almost identical signs and symptoms. This case required the effort of seven different physicians and dentists in order for the patient to be diagnosed and receive effective treatment. He could have easily been misdiagnosed as a patient with atypical facial pain, TMJ, or atypical trigeminal neuralgia. His management would likely have relied on pain medications, and he would have missed his window of opportunity for timely intervention for parotid adenoid cystic carcinoma. Resection of the tumor eliminated the painful symptoms and radiation therapy may help to prevent reoccurrence. The literature indicates that ACC is less than 1% of all malignancies and less that 10% of all salivary gland neoplasms.7

For comparison, another serious example of craniofacial pain origin was reported by Kreiner and Okeson et al. at the University of Kentucky in a 2007 prospective multi-center study:1

“Of 186 patients with ischemic cardiac episode, 11 patients or 6 percent had craniofacial pain as the only complaint. Of those 11 patients three had acute myocardial infarction (AMI). The most common craniofacial pain locations included the throat, left mandible, right mandible, and left temporomandibular joint/ear region and the teeth.”

Another 60 patients in the study (32%) reported craniofacial pain along with pain in other regions.1 Kreiner and Okeson’s study concluded that craniofacial pain is commonly induced by cardiac ischemia. However, we know not all craniofacial pain represents cardiac ischemia. Some cases of craniofacial pain may be parotid gland masses as will be seen in this article.

Clearly, a complex pain patient who suffers craniofacial pain is fortunate to be diagnosed accurately. I say this because any one of about 10 diverse medical and dental disciplines—with no organized inter-relationships—may see such a complex craniofacial pain patient. The patient may—or may not—get definitive help depending on the condition(s) and the particular examiner’s scope of knowledge and ability. This article serves to underscore the fact that a routine patient may turn out to have a life-threatening condition such as adenoid cystic carcinoma (ACC). If not diagnosed, ACC could cost them their life. The at-risk patient may not exhibit any swelling, motor or sensory deficit, and may not have any signs that would raise the suspicion index to prompt a CT scan, MRI scan, or other test. If hurting, the patient may complain of craniofacial pain that seems routinely non-fatal such as ear pain, pain in jaw, or pain in teeth.

Adenoid Cystic Carcinoma

The outcome of a diagnosis of adenoid cystic carcinoma is somewhat different than that of other salivary and secretory gland tumors.8 Adenoid cystic carcinoma (ACC) is a considered a “rare” type of tumor. ACC is most commonly found within secretory glands of the head and neck, but other sites of origin include the trachea, lacrimal gland, breast, skin, and vulva.9 For a pathologist, this type of tumor is defined by its very distinctive microscopic appearance (see Figure 1). The differential diagnosis includes other benign and malignant neoplasms that appear in these locations. For example, ACC and polymorphous low-grade adenocarcinoma (PLGA) are two forms of salivary gland cancer that share many features. But, in other sites, ACC may be misidentified on histological grounds with basaloid squamous carcinoma (a squamous carcinoma variant).

Figure 1. Histology specimen of Adenoid Cystic Carcinoma showing the typical small cell cylindrical pattern.

Signs and Symptoms

Obviously signs and symptoms depend on size of the mass and the location of site of origin. Early lesions of ACC are usually painless masses involving the mouth or face, and most of the time are growing slowly. Advanced stage tumors of ACC are usually painful and may present with nerve pain or paralysis because ACC is known to favor peripheral nerves with perineural invasion. Tumors of the lacrimal gland may interfere with vision. Tumors arising in the larynx may lead to changes in speech while tumors of the parapharyngeal space may affect the parotid gland and associated neural, vascular, and dental structures.

Clinical Course

Because of ACC’s slow and quiet growth, this malignant tumor often grows without the patient’s awareness until it affects other tissues with its insidious effect. The disease survival rate for ACC is approximately 89% at 5 years, but only about 40% at 15 years. Another unusual feature of the ACC tumor is that it seldom metastasizes to regional lymph nodes. Unfortunately the metastasis, when it does occur, shows up most often at distant sites such as the lung or the liver.10 Bone involvement usually indicates an increasingly aggressive clinical course. Features such as solid growth pattern, perineural invasion of sensory or motor nerves, or positive surgical margins of the excised specimen are considered to be indicators for a poor outcome.

Most patients are afflicted with this tumor in the fourth and fifth decades of life and it appears in females in a ratio of 3 to 2 over males. No strong genetic or environmental risk factors have been noted and, as with other tumors, damage to the DNA genome occurs early in the tumor’s development. Researchers believe there is evidence that the p53 tumor suppressor gene is de-activated in the more advanced or aggressive forms of the tumor.

Treatment

Treatment at this point relies on excisional surgery to remove the tumor and histologic examination to determine variant type, as well as to determine if the margins are clear. Many medical centers rely on radiation therapy because of anecdotal evidence that radiation helps to limit failure. There are some institutions using neutron beam treatment with favorable results, and most treatment centers do not rely on the conventional chemotheraputic drugs because of a lack of effectiveness. Several clinical trials are examining new cancer drugs to determine effectiveness against the ACC tumor.

Ernest Syndrome and Stylomandibular Ligament Injury Mimic

The initial diagnosis of Ernest Syndrome made in this case was by a dentist who suspected an injury to the stylomandibular ligament’s distal insertion at the mandible. The stylomandibular ligament is considered to be a condensation of cervical fascia, and is a first branchial arch derivative. Since the first branchial arch is provided sensory innervation by the trigeminal nerve, it follows that the sensory innervation to the stylomandibular ligament is a branch of the mandibular division of the trigeminal nerve. The ligament, in its normal state, functions to protect the mandible from hyperextension in protrusion, in forward movement, and in the wide-opening movement. It is important to note that a strain or sprain injury of the stylomandibular ligament can cause regional pain that does not reach the threshold for the classic symptoms noted in Ernest Syndrome (the latter is often a result of trauma to the head and or neck). Often the regional pain condition is reversible and is frequently a secondary feature caused by a damaged temporomandibular joint or temporalis muscle.

Typically, regional pain from a strained or sprained ligament involves pain at the gonial angle of the mandible as well as the ear. For comparison, the symptoms of Ernest Syndrome include:

  1. ear pain and stuffiness
  2. gonial angle pain,
  3. TMJ pain,
  4. retro-orbital pain,
  5. temple headache, and
  6. lower molar tooth pain.

Injury to the stylomandibular ligament may also effect some posterior restraint on the mandible which can displace the articular disc with clicking or locking of the disc in some cases. Diagnosis of an injured stylomandibular ligament is initially made by exerting digital pressure beneath the lobe of the ear at the rear margin of the mandible. Pressure typically increases the patient’s painful symptoms. A more definitive test involves the insertion of a 30 ga. local anesthetic needle trans-cutaneously and depositing ½ to one cc of local anesthetic at the posterior-medial margin of the ramus of the mandible. If the diagnosis is correct, then the anesthetic will block the symptom or symptoms for the duration of the anesthetic effect.

Case Report

In this case report, a dentist in the patient’s home area first saw the patient and concluded that the patient suffered Ernest Syndrome after first treating with a TMJ bite splint. Conservative treatment however did not affect the pain of the patient. It is significant to note that the dentist who said the patient suffered Ernest Syndrome did not, in fact, do an anesthetic block of the ligament insertion to see if the pain would be remitted. The patient in his disappointment in not improving from treatment, went to the internet and found a link to more information regarding Ernest Syndrome. The patient called our office and scheduled an exam. The exam revealed a 50 year-old male who had suffered pain around the right ear area for one year prior to my examination.

The patient listed his chief complaints in descending order as follows:

  • Pain in ear
  • Pain in jaw
  • Pain in teeth

Vital signs were normal with the blood pressure slightly elevated though the patient was on a blood pressure medication. Blood pressure reading was 130-91 and heart rate was 75. The exam was unremarkable except for the chief complaints noted. The pain quality included aching, shooting, burning, and stabbing pains of over one year duration. The patient stated nothing had abated his pain since he had been seeking help

The mandibular range of movement was within normal limits. Maximum opening was 58mm and lateral movements were 15mm, respectively. Though the patient had normal TM joint function, he had increased pain upon chewing and in opening his mouth wide. Those two complaints normally suggest to the examiner that something associated with the TM joint system is abnormal in some way (e.g. possible parotid duct obstruction). The patient was able to pin-point his most intense pain just behind the pinna of the right ear close to the transverse process of the second cervical vertebrae. That location is somewhat above the distal insertion of the stylomandibular ligament.

After explaining to the patient that a local anesthetic infiltration into the painful area may help to locate his pain, the patient agreed to a block near the styloid process. After careful aspiration, the block was given. Prior to the block, the pain level was estimated by the patient to be a 7 and, following the block, the pain level dropped to a 1. My opinion was that the block had at least masked the pain but did not define the pain origin. The volume of local anesthetic given was ¼ cc. The patient tolerated the block procedure without any side effects and was re-appointed that afternoon at which time his right stylomandibular ligament distal insertion was blocked. The results were negative and the diagnosis of Ernest Syndrome was eliminated. The patient’s family physician was then contacted and he agreed to order a CT scan of the styloid process and parotid region. The CT scan was done and was read as normal.

The patient then saw an oral and maxillofacial surgeon in his home area. The surgeon thought that the patient might have a rare calcified stylomandibular ligament. He suggested surgery after doing a styloid process area block that gave pain relief similar to my block. After speaking with the patient, I contacted the surgeon and suggested that an MRI scan be done of the parapharyngeal space to include the parotid gland before proceeding with styloid process surgery. He agreed and ordered the MRI—the results of which changed the oral surgeon’s willingness to do the proposed surgery.

The MRI scan demonstrated a tumor involving the deep lobe of the parotid gland and the carotid artery. Subsequently, an ENT head and neck surgeon removed the tumor. The histology specimen was examined and proved to be an adenoid cystic carcinoma of the deep lobe of the parotid gland. The report stated: “right parotid gland deep lobe resection: Adenoid cystic carcinoma 1.6 x 1.4 cm. Perineural invasion noted. Tumor extends to the peripheral inked surgical margins. Rare foci suspicious for lymphovascular space involvement.”

The parotid deep lobe is located medial to the mandible and lateral to the carotid artery in most cases. The ear, nose and throat surgeon who performed the resection of the parotid tumor found the mass to be pressing against the wall of the carotid artery suggesting an attachment, but was removed without incident.

Conclusion

This patient had increased pain upon chewing and pain radiating to his ear, TMJ, and the lower teeth. At initial examination the etiology was unclear. Though the CT scan did not pick up the tumor, we were fortunate to find the tumor with MRI scanning. The MRI scan revealed a mass that was close to the medial wall of the mandible, and its proximity explained the referred pain to the ear, jaw joint, and teeth.

The cancer management team recommended extraction of six mandibular teeth before radiation therapy could be initiated. Ultimately, thirty-five radiation treatments were done and the patient has recovered very well from the surgery and the radiation treatments. He is scheduled for periodic follow-up with his surgeon. The patient no longer suffers any of the original symptoms for which he presented at the initial examination.

The possible diagnosis of Ernest Syndrome considered by the TMJ dentist actually proved to be helpful as that opinion started the patient’s process of discovery that ultimately led to the tumor.

Not every case of craniofacial pain that appears to be Ernest Syndrome is in fact Ernest Syndrome11-12 as was seen in this case. The TMJ dentist fortunately did not persist in a treatment of the stylomandibular ligament that ultimately was without benefit to the patient. When the dentist informed the patient that he could not help with his pain problem, the patient wisely took his health issues into his own hands and persisted in seeking more information. Information was found on the internet that provided a direction that ultimately led to his receiving help for his confusing condition.

I must say that this case did not present with a clear-cut diagnostic picture. There were several “dental-like” symptoms that suggested the jaw joint as the problem: ear, jaw, and tooth pain as well as pain on chewing and opening wide. However, none of those symptoms were related to an injury of the jaw joint, teeth, or neuralgia. All of the pain suffered was a primary result of a growing mass that eventually affected branches of the trigeminal nerve with perineural invasion, the carotid artery, and the parotid gland, as evidenced by the pathology report.13

As stated earlier in this article, the ultimate outcome for this patient is dependent on two possibilities: 1) the chance for re-occurrence and 2) the possibility of metastasis at a later period. Hopefully neither will occur.

Last updated on: March 22, 2011
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