Stylohyoid Syndrome and its Surgical Treatment – A Case Report and Review of the Literature

A 45-year-old male patient presented to the oncology center at Mansoura University, complaining of a dull-aching intermittent pain in left upper neck region of ten months duration, the pain was radiating to oropharynx, the patient also gave a history of long standing intermittent odynophagia and a foreign body sensation in the throat. The pain is exacerbating with turning the head to the right side. There was no recent history of tonsillectomy or any other cervicopharyngeal trauma. The patient sought medical advice at a dental, otolaryngeology and neurology clinics with no improvement. Cancer phobia was the drive that made the patient seek service at our oncology center since his father has had nasopharyngeal carcinoma.


Introduction
Stylohyoid syndrome or Eagle syndrome or stylalgia is an uncommon syndrome that affects about 4% of population and is more common in middle aged females between 30-50 years [1,2].
The aetiology of this syndrome was reported to be due to anatomical or pathological elongation of the styloid process or calcifi ed stylohyoid ligament. Eagle defi ned the length of a normal styloid process at 2.5-3.0 cm [1,3,4].
In most instances this syndrome is diagnosed incidentally or by exclusion due to its rarity and heterogeneous symptomatology, nevertheless its primary symptom is oropharyngeal pain or stylalgia which may radiate to the ear and may be exaggerated by head movement or even chewing, yawing and speaking [5,6].
The diagnosis of this syndrome therefore represents a challenge [7]. Patients with eagle syndrome may pass undiagnosed or even receive psychotherapy being diagnosed as having a psychological disturbance rather than an organic disease.
Stylohyoid syndrome can be successfully treated by surgical styloidectomy either intra or extra-orally (transcervical), however, some authors reported successful conservative medical treatment [8-10].
We hereby reporting a patient of stylohyoid syndrome who sought medical advice at different clinics without relief and lastly he came at our oncology clinic for exclusion of malignancy due to his cancer phobia as his father has had nasopharyngeal carcinoma where we suspected stylohyoid syndrome and was proved by the 3D reformatted CT.

Case presentation
A 45-year-old male patient presented to the oncology center at Mansoura University, complaining of a dull-aching intermittent pain in left upper neck region of ten months duration, the pain was radiating to oropharynx, the patient also gave a history of long standing intermittent odynophagia and a foreign body sensation in the throat. The pain is exacerbating with turning the head to the right side. There was no recent history of tonsillectomy or any other cervicopharyngeal trauma.
The patient sought medical advice at a dental, otolaryngeology and neurology clinics with no improvement. Cancer phobia was the drive that made the patient seek service at our oncology center since his father has had nasopharyngeal carcinoma.

Abstract
Stylohyoid syndrome or eagle's syndrome is caused by calcifi cation of the stylohyoid ligament or elongation of the bony styloid process. It may remain asymptomatic or it may present with facial neuralgia, foreign body sensation in pharynx, throat pain or even otalgia and cephalgia. Diagnosis is mainly based on clinical examination and confi rmed by the radiological fi ndings. The mainstay treatment is surgical excision via external approach or intraoral approach. We are reporting a case of unilateral stylohyoid syndrome along with the literature review.

Discussion
Stylohyoid syndrome or stylalgia was primarily called eagle syndrome, due to its fi rst documentation by the otolaryngologist Watt W eagle in 1937. It may be unilateral or bilateral [3], the prevalence of this syndrome was primarily thought to be 4% of population then claimed to be as low as 1.4% [11], and then reported to be as high as 30% by Keur et al., in 1986 [12].  [3,4,14]. Therefore, anatomical or pathological abnormalities in the length and/or direction of the styloid process or calcifi cation of its attached ligaments could lead to variable degrees of compression on these related important neurovascular structures expressing variable degrees of clinical symptoms ranging from no symptoms [15], or phantom foreign body sensation in throat to compressive cranial neuropathy most commonly presenting with odynophagia and radiating otalgia (classical type of eagle syndrome) or even compression over the internal carotid artery leading to pain in the parietal region of the skull or in the superior periorbital region or even cerebral ischemia (stylocarotid type of eagle syndrome [6,16,17] (Figures 4,5).
The clinical symptoms are vague and variable and had other several differential diagnoses [10]. Two clinical signs are considered pathognomonic or characteristic to this syndrome which are tenderness elicited while palpating the components of the stylohyoid complex especially at the tonsillar region and the rare presence of a tender bony projection on the ipsilateral submandibular region anterior to the sternocleidomastoid muscle [18].
History of tonsillectomy or cervicofacial trauma may be typically found in many patients with classic type eagle syndrome due to resultant traumatic scarring and hyperplasia in stylohyoid complex [3,16]. Nevertheless, inherited familial ossifi cation or embryonic ossifi cation or osteoarthritis changes within the stylohyoid complex are all reported as possible etiologies of this syndrome [1,19]. The presence of associated psychological problems is described by some authors [20].
Radiological imaging with computed tomography especially with 3 D reformatted images is considered the optimal   method for confi rmation of eagle's syndrome diagnosis [1,21,22], however, Eagle syndrome cases that result from stylopharyngeus muscle calcifi cation may be missed by this type of imaging [5]. In our case, we believe that the length given by the radiologist is the combined length of the left styloid process and the calcifi ed part of the stylohyoid ligament which was 6.7 on the left side.
The diagnosis of this syndrome represents a challenge not only because of its rarity but also due to its vague and heterogeneous symptomatology and several available different differential diagnoses, which include trigeminal neuralgia, glossopharyngeal neuralgia, temporomandibular joint dysfunction, carotidynia, atypical migraine temporal arteritis, salivary gland problems, chronic tonsillitis, pharyngeal tumors, laryngopharyngeal refl ux, dental problems, , otitis externa or media, and mastoiditis [5], so diagnosis requires good awareness of this condition together with high index of suspicion, furthermore it might be suspected in those patient having psychiatric problems [6,7,23].
Treatment of this quite rare clinical entity is mainly surgical by excision of the elongated styloid process with or without the calcifi ed stylohyoid ligament and/or elongated hyoid bone via an extra-oral or intra-oral approach [8,24]. Some authors advocated the intra-oral approach for cases with styloid bony process elongation; and the extra-oral approach for ossifi ed stylohyoid ligament or elongated hyoid bone cornu [5]. Naik reported successful treatment of 15 cases of eagle's syndrome with tonsillo-styloidectomy. [10]. Interestingly, Maru K and Patidar K. reported successful transoral styloidectomy under local anaesthesia in 332 patients with stylohyoid syndrome [25].
Others reported successful treatment of this syndrome with conservative non-surgical modalities including analgesics, pain killers, antidepressants, local injection of local anesthetics and steroids in peritonsillar region and stellate ganglion block [9,26], however, we and other authors do believe that conservative medical treatment provides only a temporary relief and cannot replace surgical treatment [26,27].

Conclusion
Stylohyoid syndrome is not extremely rare and is more