Imaging Of Paragangliomas

Paragangliomas are also called glomus tumors. Paragangliomas or glomus tumors occur in a variety of sites in the head and neck with almost half arising in the bone which comprises the side of the head/skull (temporal bone). Treatment management of paragangliomas best represents the need for a multi-specialty medical approach to treat this non-cancerous tumor (benign neoplasm) of the head and neck, cervical, and temporal regions.

The interesting features of paragangliomas or glomus tumors include their simplicity and their frequent association with other neurological tumors that have their origins in the neurological tissue of the developing embryo. Examples of other in this grouping include: glomic tumors, chemodectomas, nonchromaffin paragangliomas, and neurocristopathic tumors.

For practical purposes, paragangliomas are commonly divided on their locations and include: tympanic paragangliomas, jugular paragangliomas, carotid body paragangliomas, vagal paragangliomas, laryngeal paragangliomas, nasopharyngeal paragangliomas, and orbital paragangliomas. For practical purposes, it is a times difficult to differentiate tympanic and pure jugular paragangliomas, and therefore, they are considered as temporal paragangliomas.

Paragangliomas (glomus tumors) are also considered part of the APUD system, and therefore, have been also called apudomas. Although, they appeared to be neoplasms, there is evidence of a familial distribution, which is not restricted exclusively to branchial paraganglia tumors but applies to all apudomas. In familial cases, the inheritance is autosomal dominant with strong penetrance but variable expression.

Paragangliomas not infrequently may be multifocal and they being not only in one location that may actually be bilateral on both sides of the head and neck. The vagal and carotid paragangliomas are most likely to be multifocal then those in other locations. In up to 17% of paragangliomas, there may be a functionally active tumor, which may present with uncontrollable hypertension. Multicentricity and secretory activity can be observed with malignant paragangliomas (glomus tumors). The malignant character of this lesion is difficult to assess at the time of pathology and only the presence of positive lymph nodes involved or metastasis can be considered a reliable indicator. The incidence of malignant paragangliomas is not determined.

These (glomus tumors) are very vascular and are the most vascular tumors of the benign type in the head and neck. Paragangliomas are also considered to be either single compartment (mono-compartmental paragangliomas) or may have multiple compartments (multicompartmental paragangliomas). Paragangliomas are not only be very vascular tumors but may actually invade vascular channels such as the jugular vein or venous sinuses. They may also be surrounding important arteries such as the carotid artery.

Spontaneous regression of paragangliomas (glomus tumors) has never been reported. The growth of paragangliomas is generally slow but it can be rapid or associated with additional tumors in other territories.

Clinical aspects of paragangliomas, two clinical aspects of branchial paragangliomas should be considered; the tumor itself and the neurocristopathy.

The symptoms of paragangliomas are related primarily to their location. Therefore, three important syndromes can be described. Tympanic, jugular, and corticovagal paragangliomas with symptomatology of mass, bruit, cranial nerve paralysis, pain, which is usually progressive compatible with a tumor. It may fluctuate at times. At times, there may be some hemorrhage within the tumor itself or around the tumor bed producing an inflammatory reaction.

Paragangliomas (glomus tumors) located in the temporal region may present with one or multiple of the following symptoms. Hearing loss, perceptive or conductive. A pulsatile tinnitus, seventh nerve paralysis or facial paralysis, discharge from the ear, pain, vertigo, hemorrhage from the ear (otorrhagia), lower cranial nerve paralysis or mass affect.

Jugular paragangliomas typically present with what is called a jugular foramen syndrome, which includes paralysis of the fourth, fifth, and eleventh cranial nerve. At this stage, they are usually large tumors. The fourth nerve paralysis can produce double vision, fifth nerve paralysis may present with some numbness of the face and the eleventh cranial nerve may present the problems of moving the shoulder. When the tumor extends beyond the jugular foramen, it may involve the twelfth cranial nerve, which may produce paralysis and/or weakness of the movement of the tongue.

Cervical paragangliomas are being called a cervical mass but some specific findings can help differentiate the tumors that involve the tenth nerve of vagus from those that involves the carotid artery. Caroid paragangliomas present with a pulsatile expansile mass when they occur as a simple, isolated lesion, they may have less symptoms. However, although the mass is typically in the neck, it may extend into the parapharyngeal spaces.

Carotid paragangliomas may present with pain, vocal cord problems with hoarseness, syncope, difficulty in swallowing (dysphagia), problems with the eye (Horner syndrome), and paralysis of the tongue (twelfth nerve deficit).

Vagal paragangliomas may present with paralysis to the lower cranial nerves, which includes the tenth cranial nerve, which may present with paralysis of the diaphragm, twelfth cranial nerve paralysis with paralysis of the tongue, problems in swallowing, and problems with raising the shoulder.

Less frequently paragangliomas (glomus tumors) may be in contact in atypical locations in the head and neck that may require a biopsy for diagnosis. This includes the nasopharyngeal region or other less frequent areas of the head and neck.

The endocrine activity of some paragangliomas may occur in up to 17% of patients. The secretory activity may involve the release of catecholamines. The symptoms may include headaches, hypertension or high blood pressure, palpitations, excessive sweating, and anxiety. At time of treatment, there may be crisis from the release of the hormones that this paraganglioma secrete.

This include prominent jugular bulb, intratympanic course of the internal carotid artery, stapedial artery persistence, granuloma in the tympanic cavity, neurogenic tumor, meningiomas, metastasis, and hemangiomas.

This includes lymphadenopathy, which represents swelling of the lymph nodes, a brachial cleft cyst, metastasis from thyroid lymphoma or Hodgkin's, neurogenic tumors, aneurysms, and dolichocarotid sinus.

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