Introduction

Paragangliomas comprise 0.6% of all neoplasms in the head and neck. Most paragangliomas are carotid body (glomus caroticum) or glomus jugulare tumors. Glomus vagale and tympanicum tumors are less prevalent(₁). The carotid body tumor is a rare neoplasm that has generated much literature over the last century, and for which continued controversy exists regarding natural history, biologic behavior, proper technique of excision, and the risk of morbidity and mortality(₂). Glomus caroticum had been first defined by von Haller in 1743. Initial two attempts for surgical treatment by Reigner in1880 and by Mayden in 1886 had failed. First successful intervention had been carried out by Scudder in 1903 (₃). Excision of tumor is the best treatment modality. But, complications such as intraoperative bleeding, injury to the vessels and nerves make the surgical intervention difficult (₁). Due to the developments in preoperative diagnostic tools and improvements in surgical and anaesthetic techniques, perioperative complication rate decreased.

Case Presentation

Our case was a 39-year-old female who had been suffering from neck pain for 2 years. In another institution she had been investigated with ultrasound of thyroid gland and Doppler ultrasound of carotid artery revealing a left glomus caroticum tumor accompanied by a giant thyroid nodule. Thereby, she had been referred to our institution for surgery. Her color Doppler ultrasound showed a hypervascular, smooth in contour mass of 1.5x2x2.5 centimeters corresponding to glomus caroticum (Figure 1).

Figure 1

Figure 1: Color Doppler ultrasound image showing glomus caroticum.

Thyroid gland ultrasound showed a giant nodule of 42 millimeters in diameter, possibly benign in nature, located at the junction of the right lobe and isthmus. It contained hypovascular punctate calcified and degenerated areas centrally, surrounded by peripheral vascularization (Figure 2).

Figure 2

Figure 2: Ultrasound image of thyroid gland showing giant nodule.

She had no other symptoms like dysphagia, hoarseness, nasal obstruction, and epistaxis. No family history of glomus tumors was reported. On examination, a semi-mobile mass was palpated in the right jugulodigastric region. Her blood pressure was within normal limits and the systemic physical examination findings were normal, except for the mass. Preoperative information was derived from magnetic resonance imaging (MRI) after color Doppler imaging. MR imaging examinations were performed with a 1.5 T unit MR imaging scanner. During MRI, after administration of the paramagnetic agent, fat-suppressed T1-weighted axial slices were taken showing a mass lesion located at left carotid bifurcation. This lesion was 25 millimeters in diameter that contrasted well. It was evaluated as glomus caroticum regarding its localization and signaling morphology (Figure 3).

Figure 3

Figure 3: MRI view of glomus caroticum tumor.

Again, MR images at the Spinecho T1-weighted axial sequences showed a degenerated giant thyroid nodule of 30 millimeters in diameter located at the right lobe extending to isthmus. It contained heterogenous bleeding and calcific components (Figure 4).

Figure 4

Figure 4: MRI view showing a giant degenerated thyroid nodule.

After these investigations, Department of Endocrinology recommended that intervention to glomus caroticum before the giant nodule would be better. Then, the patient was taken to the operation.

Surgical technique

Neck exploration was done through an incision along the anterior border of the sternocleidomastoid muscle. After the skin incision, subcutaneous tissues and platysma muscle were cut and sternocleidomastoid muscle was deviated laterally. Common carotid, internal and external carotid arteries were exposed and suspended.Special care was taken to avoid injury to the cervical branch of the facial nerve, hypoglossal nerve, vagus nerve. Macroscopic exploration defined a multilobular mass pushing the internal jugular vein laterally, surrounding carotid artery tightly and showing definite adhesions to the neighboring tissues (Figures 5 and 6).

Figure 5

Figure 5: Macroscopic view of the multilobular glomus caroticum tumor

Figure 6

Figure 6: Total extirpation of the mass from carotid bifurcation.

In our case, ligation of the external arteries was not needed. Removal of the mass from carotid arterial adventitia was carried out without damaging the surrounding vascular and cranial nerve tissues (Figure 7).

Figure 7

Figure 7: Operative picture showing excision of carotid body tumor, sparing carotid vessels.

A drain was placed and the wound was closed after securing the hemostasis. All of the excised specimen was sent for histopathological examination.During perioperative and early postoperative period no mortality did occur. There was no need for perioperative blood transfusion since no massive hemorrhage was seen. There weren't any injuries to the neighboring vascular and cranial nerve structures experienced. Histopathological evaluation concluded that this mass was a paraganglioma (glomus caroticum tumor). Her hospital stay took 3 days long. Her late postoperative follow-up is still free of symptoms. During the follow-up period, there was no tumor recurrence.

Discussion

Glomus caroticum tumors are slowly enlarging, neuroectodermal, rare tumors. Carotid body tumors are reported to be the most common head and neck paraganglioma, accounting for 60 to 78% of tumors (₄). Multiple, often bilateral, carotid body tumors represent ~10% of sporadic and 25 to 33% of familial cases (₄,₅). These tumors grow slowly and are said to have a median doubling time of 4.2 years. Without therapy they may grow to a considerable size and become life-threatening (₄,₆). They tend to show a locally aggressive and infiltrative growth pattern, destroying surrounding structures (₄). Malignancy occurs in 6–12.5% of cases, which ranks carotid body paragangliomas as the most frequently occurring malignant head and neck paraganglioma (₂,₈). Metastasizing carotid body tumors have been reported to develop in fewer than 5% of cases (₄).

Patients are typically middle- aged and present with a painless, slow-growing neck mass or neurootological symptoms (₁,₉). It is seen more frequently in people living at high altitudes (₂). Doppler ultrasound is proved to be an exclusive method in demonstrating the localization of tumor and defining its vascular origin (₁₀). Glomus tumors, especially with some definitive MR imaging features, are diagnosed easily(₁). To avoid injury during surgery, a careful preoperative evaluation of the extent of the tumor, including its relationship to neurovascular structures and the possibility of synchronous glomus tumors, is important for planning the appropriate surgical procedure (₁,₁₁). The role of MR imaging in the diagnosis and preoperative assessment of paragangliomas is well established. MR imaging characteristics of all paragangliomas are similar. A well-defined hypointense mass with approximately equal signal intensity to adjacent muscle, with areas of signal void is typically seen on T1-weighted MR imaging. T2-weighted images also demonstrate a well-defined mass, which is heterogeneously hyperintense, with greater signal intensity than muscle. Contrast-enhanced imaging shows intense tumor enhancement, which is a key finding in the diagnosis. Punctate flow voids are seen and are believed to represent the hypervascular nature of this tumor. In larger lesions, a salt-and-pepper appearance on T1- and T2- weighted images is characteristic of paragangliomas (₁,₉). The relationship of a paraganglioma to the adjacent carotid artery and/or jugular vein is well demonstrated by MR imaging. This demonstration may help differentiate carotid body tumors from vagal paragangliomas. Carotid body tumors tend to splay the internal carotid artery and external carotid artery, and thus widen the carotid bifurcation (₁,₁₁).

Currently, three treatment options are recognized: surgical resection, radiation therapy, and a wait-and-scan policy (₄). Surgical treatment has been the standard approach to cervical paragangliomas for many years. Cure rates of 89 to 100% have been reported (₄,₁₂). Advances in preoperative and operative techniques together with better postoperative care have reduced complication rates. Preoperative cranial nerve deficits have been reported in 20% of patients with carotid body tumors(₁₂). Because these are close to the important vessels and nerves there is risk of morbidity and mortality (3–9%) (₂,₁₃). The risk seems to be significant when the tumor size is more than 5 cm (67% in >5 cm and 15% when <5 cm). Shamblin developed a classification system for the carotid body tumors in 1971 (₅). Group 1 tumors are those which can be easily dissected from the adjacent vessels, group II tumors include those which are moderate in size adherent but separable from the adjacent vessels with careful dissection, and grade III tumors are usually large and engulf the carotid vessels necessitating partial or complete resection and replacement of the carotid vessels. The risk of cranial nerve palsy as a complication of carotid body tumor surgery has been reported to range from 10 to 40% (₄,₁₄,₁₅). As would be expected, the rate of neural complications is greater in patients with Shamblin II and III tumors (₄). There was no correlation between the tumor size and incidence of cranial nerve palsies. The rate of major vascular complications has dropped from 30% in the 1960s to less than 1% in most recent reports (₄,₁₅)

There are different opinions regarding use of shunts perioperatively. It has been reported previously that shunt usage may cause particle embolization and injury to the distal intima, thus causing neurologic complications. Usage of shunt during resection of the tumor is necessary when the stump pressure of internal carotid artery drops to below 50 mm Hg. This maneuver decreases the risk for cerebral infarction. Occlusion of the internal carotid artery may cause ischemic stroke in more than 30% of cases and therefore intraluminal shunting is necessary. In this way, a trauma due to clamping of a fragile artery like internal carotid artery would not ocur and more distal exploration of the artery may become optimal (₁₆). Selective embolization of the nutritional arteries preoperatively is generally recommended for tumors larger than 4 centimeters in diameter, thus obtaining a bloodless surgical field (₁₇). But, some authors emphasize that intracranial embolization is a precursor of neurologic deficit causing stroke and other serious complications. Therefore, these claim that embolization should be avoided (₁₈).

Treatment must be individualized, taking into account the patient's age, tumor site and size, multicentricity, and pre-existing cranial nerve deficits. The likelihood of tumor control is high whether treatment is by surgery or radiotherapy (₄). In general, patients with solitary lesions that are potentially resectable with acceptable morbidity are better treated surgically. For patients with multiple tumors, treatment options will be influenced by the location of the tumors, age of the patient, comorbidities, and whether past radiotherapy has been given (₄). Most authors still recommend radiotherapy only for very large tumors, recurrent tumors or for those patients who are poor surgical candidates (₂). As it is a very slow growing tumor with a growth rate of less than 0.5 cm per year, small tumors in old patients, with significant risk factors for surgical interventions, can be managed by observation only (₂,₁₉).

In summary; surgical resection is a curative therapy for glomus caroticum tumors. Although surgical resection is the best therapy, it must be performed as early as possible and planned carefully taking into account its complications. A complete preoperative evaluation is necessary for safe resection of the tumor and reconstruction of the artery (₂,₂₀).

Correspondence to

Doç. Dr. Ufuk YETKIN 1379 Sok. No: 9,Burç Apt. D: 13 35220, Alsancak – IZMIR / TURKEY Tel: +90 505 3124906 Fax: +90 232 2434848 e-mail: ufuk_yetkin@yahoo.fr