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1

What are paragangliomas? From what tissues are they derived?

What are paragangliomas? From what tissues are they derived?

Paragangliomas are benign or malignant vascular soft tissue tumors that arise anywhere paraganglia that have a neural crest origin are present. Paraganglia are present in the vascular adventitia or intraneuronally, releasing catecholamines and neurotransmitters. Most degenerate after birth but some persist, primarily along the autonomic nervous system.

2

What are the commonly used and confusing names for paragangliomas?

What are the commonly used and confusing names for paragangliomas?

These tumors have various terminologies such as chemodectoma, nonchromaffin paragangliomas, carotid body tumors, and glomus tumors. Due to the physiologic function of the carotid body as a chemoreceptor, carotid body tumors are known as chemodectomas. Chemodectoma only applies to carotid body paragangliomas as the carotid body and aortic body are the only paraganglia that act as chemoreceptors.Nonchromaffin refers to the histologic staining that distinguishes all paragangliomas from the chromaffin-reacting tissue of the adrenal medulla. Glomus is the most frequently misused term in the literature as it is technically a term for a histologically different benign cutaneous tumor. The WHO has designated these paragangliomas by their location (i.e., carotid, vagal, jugular, and tympanic paragangliomas).

3

Where are paragangliomas commonly found?

Where are paragangliomas commonly found?

The most comon site is the adrenal medulla (pheochromcytoma) with 90%, followed by abdominal (8.5%), thoracic (1.2%), and then head and neck (0.3%). The carotid body bifurcation (carotid body tumor) is the most common location of a head and neck paraganglioma. Jugular paragangliomas (glomus jugulare) is the next most common head and neck, followed by paragangliomas on the promontory of the middle ear (glomus tympanicum) and vagal paragangliomas. Rare locations can include the larynx, thyroid, paranasal sinuses or any other structures that harbor paraganglia.

4

How do paragangliomas present?

How do paragangliomas present?

Most paragangliomas are discovered incidentally on imaging. Carotid body tumors typically present with a pulsatile neck mass that is mobile in the horizontal direction but not vertically. The growth rate is estimated at 0.5 cm per year. Tympanic paragangliomas are found on otoscopy as a bluish mass behind the eardrum. Because of their location in the temporal bone, the presenting symptoms can include pulsatile tinnitus and cranial nerve involvement (IX, X, and XI), if large.

5

Is a tympanic paraganglioma (glomus tympanicum) the same as a jugular paraganglioma?

Is a tympanic paraganglioma (glomus tympanicum) the same as a jugular paraganglioma?

No. Tympanic paragangliomas arise in the middle ear on the promontory of the cochlea. The morbidity associated with surgical resection is minimal. They present with pulsatile tinnitus, conductive hearing loss, and/or a blue mass behind the tympanic membrane on examination. Jugular tumors arise from paraganglionic tissue in the jugular bulb. Their site of origin is in the temporal bone, and their growth creates a great deal of bony destruction. Tumors of the jugular foramen put the IX, X, and XI nerves at risk, and resection in this region involves a combined skull base procedure and can result in significant cranial nerve related morbidity.

6

What is the most important aspect of working up a paraganglioma patient?

What is the most important aspect of working up a paraganglioma patient?

It is important to gather a thorough history to assure there are no signs of a functional tumor (flushing, heat intolerance, palpitations, etc.). If there are, evaluate urinary metanephrines and vanillylmandelic acid (VMA) and serum catecholimines, and strongly consider an endocrinology referral if positive. Functional tumors are rare and only comprise approximately 1% to 3% of paragangiolmas in the head and neck. The next most important aspect is the physical examination, which should include a comprehensive cranial nerve examination.

7

What is the ideal imaging for paragangliomas?

What is the ideal imaging for paragangliomas?

A computed tomographic scan with contrast or magnetic resonance imaging with gadolinium (and CT/MR angiography if needed) will often provide the diagnosis and superior anatomic extent. Vascular flow voids are often demonstrated on imaging, which strongly predict a paraganglioma. Ultrasonography may be helpful on intial examination to determine the difference between a vascular tumor and lymph node. Angiography was very common prior to CT or MR angiography technology but is now reserved for preoperative embolization if the surgeon desires. The classic angiography of a carotid body paraganglioma is splaying of the internal and external carotid artery at the bifurcation (Lyre’s sign) (Figure 17-1).

8

What is the inheritance pattern of familial paragangliomas?

What is the inheritance pattern of familial paragangliomas?

Although most paragangliomas are sporadic in nature, up to 30% are familial. A higher incidence of multicentric tumors exists in patients with the familial pattern (30% to 40% versus 10% in sporadic paragangliomas). Familial parangliomas are inherited in an autosomal dominant fashion with genomic imprinting. Fifty percent of the offspring of males with the gene develop paragangliomas, but when transmitted by the mother the gene is swiched off and the offspring will not exhibit the disease. The primary gene (PGL1) codes for the succinate dehydrogenase complex; malignant paragangliomas are more common with SDHB patients.

9

Discuss the treatment options for paragangliomas.

Discuss the treatment options for paragangliomas.

Options for treatment inlude surgery, observation, and radiation, depending on the patient-oriented factors, growth rate, malignancy potential, and multicentricity. Tumors often remain stable for many years or grow very slowly, so observation may be reasonable in some. Classically, surgery remained the mainstay of treatment, and it is the only way to fully eradicate a tumor. However, over the years a more conservative approach based primarily on patient factors (age, comorbidities, cranial nerve deficits, growth rates) has been taken due to the potential for surgical morbidity in certain cases (jugular or vagal paragangliomas, bilateral carotid body tumors).

10

What is the classic histology of a paraganglioma?

What is the classic histology of a paraganglioma?

There are three types of cells: capillaries, chief cells (Type I), and sustentacular cells (Type II). The pattern in which these cells are arranged is termed Zellballen. These tumors are highly vascular and are of neural crest in origin.

11

Can malignant potential of a paraganglioma be determined on histologic analysis of the primary tumor?

Can malignant potential of a paraganglioma be determined on histologic analysis of the primary tumor?

No. Paragangliomas have a low potential for malignancy and the only method to determine malignancy is the presence of tumor in the lymph nodes or distant metastases. Vagal paragangliomas have the highest malignant potential (16%) compared to carotid body (6%) and jugulotympanic (4%) tumors.

12

Discuss the management of jugular paraganglioma.

Discuss the management of jugular paraganglioma.

Jugular paragangliomas typically arise in the temporal bone and are usually associated with significant bone destruction. They typically involve structures of the jugular foramen (cranial nerves IX, X, and XI). Surgical resection involves radical skull base surgery and frequent compromise of these cranial nerves. Preoperative cranial nerve examination is critical because surgery can result in aspiration, dysphagia, and possible facial nerve injury; such risks make radiotherapy an attractive alternative. However, for younger patients and those whose cranial nerves have already been compromised by the tumor, compensation often will have happened preoperatively. These patients do much better with surgery than those whose cranial nerves are normal. With modern skull base techniques, total resection with excellent rehabilitation of the patient is possible; however, radiation should be strongly considered based on patient-oriented factors.

13

What can happen if bilateral carotid body (or one vagal and one carotid body tumor on opposite sides) tumors are excised (Figure 17-2)?

Bilateral denervation of the carotid bodies results in severe paroxysms of hyper- and hypotension and is termed baroreflex failure. These are managed in the perioperative period with sodium nitroprusside, clonidine, phenoxybesamine, and antianxiety medications (anxiety can exacerbate fluctuations). Compensation can occur but the rate and timing of this is variable. In these situations, unilateral radiation or observation should be considered for at least one of the tumors.

What can happen if bilateral carotid body (or one vagal and one carotid body tumor on opposite sides) tumors are excised (Figure 17-2)?

Bilateral denervation of the carotid bodies results in severe paroxysms of hyper- and hypotension and is termed baroreflex failure. These are managed in the perioperative period with sodium nitroprusside, clonidine, phenoxybesamine, and antianxiety medications (anxiety can exacerbate fluctuations). Compensation can occur but the rate and timing of this is variable. In these situations, unilateral radiation or observation should be considered for at least one of the tumors.

14

What is the role of radiation therapy in the management of paragangliomas?

What is the role of radiation therapy in the management of paragangliomas?

Improved techniques and more experience with radiating paragangliomas have demonstrated a 90% control rate of benign tumors, defined as cessation of growth or regression. It is extremely rare for tumors to completely resolve. With newer techniques and doses of 45 gy for standard fractionation typically given, complications are rare. Nevertheless, most individuals still prefer surgical excision of lesions.

15

A 12-year-old boy presents with a history of unilateral nasal obstruction and heavy episodes of epistaxis. Physical examination reveals a large, purplish mass filling the nasopharynx. Should you biopsy this mass?

A 12-year-old boy presents with a history of unilateral nasal obstruction and heavy episodes of epistaxis. Physical examination reveals a large, purplish mass filling the nasopharynx. Should you biopsy this mass?

No. Your next step should be a contrast CT to evaluate for a likely juvenile nasopharyngeal angiofibroma, which occurs exclusively in males, often presenting with nasal congestion, unilateral nasal obstruction, epistaxis, and sometimes anosmia. These tumors are hormonally responsive and usually occur during adolescence. Although they are histologically benign, they may be locally invasive and have the potential to extend intracranially. Treatment involves surgery, with or without preoperative embolization. Radiation therapy is reserved for unresectable cases. These vascular tumors are associated with a high recurrence rate if not excised fully, but eventually regress once the patient reaches adulthood.

16

An infant develops a rapidly enlarging hemangioma on her cheek. What is the appropriate treatment?

An infant develops a rapidly enlarging hemangioma on her cheek. What is the appropriate treatment?

Counsel on the natural history of these lesions and try to avoid surgery. Hemangiomas are the most common head and neck tumors in children. They are more frequently found in females than males (3 : 1). The typical history is a period of rapid enlargement followed by gradual involution. Fifty percent have involuted by the age of 5 years, and 70% by age 7.

17

A child with a large facial hemangioma develops a coagulopathy. What is this entity? How is it managed?

A child with a large facial hemangioma develops a coagulopathy. What is this entity? How is it managed?

This is a disseminated intravascular coagulation–like syndrome with platelet trapping in the tumor and is termed Kasabach-Merritt syndrome. It is treated by transfusion of clotting factors and platelets as necessary, in addition to addressing the responsible lesion.

18

A child with a facial hemangioma presents with stridor. What is your presumed diagnosis and next steps?

A child with a facial hemangioma presents with stridor. What is your presumed diagnosis and next steps?

Subglottic or other airway hemangioma. Direct laryngoscopy and bronchoscopy is warranted with the possibility for a tracheostomy if the airway is severely compromised. Hemangiomas may occur in the airway as well as on the skin. About 50% of children with subglottic hemangiomas also have cutaneous lesions. Medical therapy may consist of steroids and/or beta-blockers.

19

A young male presents with a port-wine stain of the right face. What is your diagnosis?

A young male presents with a port-wine stain of the right face. What is your diagnosis?

Sturge-Weber syndrome. This is a congenital syndrome of unknown etiology charaterized by port-wine nevi in the distribution of the first and second trigeminal branches as well as angioma of the cerebral leptomeninges. It is important to have neurology and ophthalmology evaluations and imaging of the brain, as this syndrome can involve seizures, brain calcifications, and ophthalmologic findings. Port-wine stains can be managed with laser therapy.

20

What types of lasers are used to treat cutaneous vascular lesions?

What types of lasers are used to treat cutaneous vascular lesions?

The laser best suited for cutaneous vascular lesions is currently the pulsed-dye laser. It is excellent for port-wine stains. Argon and potassium titanyl phosphate (KTP) lasers have wavelengths specific for hemoglobin, which enhances their ability to treat such lesions. Yttrium-aluminum-garnet (YAG) lasers (and also argon lasers) have been associated with the involution and arrest of growth of hemangiomas, although a conservative approach is usually preferable for these lesions.

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