Paraganglioma

Epidemiology

Paragangliomas are slow-growing tumors arising from paraganglion cells of neural crest origin. They may be found along the superior cervical ganglion of the vagus nerve situated in the jugular foramen (glomus jugulare), around Arnold’s or Jacobson’s nerves in the middle ear (glomus tympanicum), along the nodose ganglion of the vagus nerve (glomus vagale) and the carotid bifurcation (carotid body tumor). These lesions show a female preponderance and are most commonly seen in middle age. Paragangliomas are multiple in 3 to 5% of patients but the incidence rises to 20 to 30% in patients with a positive family history.

Clinical Findings

Clinical presentation depends on the site of origin. Although all these tumors contain norepinephrine and epinephrine precursors, secretion of significance is very rare. This is related to the relative sparsity of secretory granules in these tumors. Carotid body tumors usually present as painless pulsatile neck masses. Similarly, glomus vagale may present as a painless lump but may show signs of vagus nerve dysfunction. Glomus jugulare usually presents with symptoms of nerve compression involving cranial nerves IX through XI. Pulsatile tinnitus is also common.

Pathology

The tumor consists of clumps of neoplastic cells separated by numerous slitlike vascular channels in a matrix of fibrous tissue. These tumors are histologically benign but may exhibit malignant behavior in less than 5% of cases. A diagnosis of malignancy is based on clinical behavior rather than on histological features. Regional nodal metastasis is present in 50% with malignant paragangliomas. Most cells stain positive for chromogranin.

Treatment

The preferred management is surgical resection. Small tumors can be resected without significant blood loss or nerve injury. Large vascular lesions may be embolized prior to resection. Tumors that are surgically inaccessible may be treated with radiation therapy.