[Clinicopathologic study of four cases of vagal paraganglioma]

To determine if pathologic examination can be useful in both diagnosing cervical paraganglioma and deducing its vagal origin.

Four cases of vagal paraganglioma were studied by light microscopy and immunohistochemistry, with clinical and radiologic (computerized tomography and/or magnetic resonance imaging) correlation.

All patients were females and complained of upper neck mass with symptoms and signs of vagus nerve involvement, such as hoarseness of voice, ipsilateral vocal cord dysfunction and cough induced by drinking or local pressure. Radiological examination showed a tumor mass over the common carotid artery bifurcation, lying between the internal carotid artery and internal jugular vein. On gross inspection, the stump of the resected vagus nerve could be identified, with nerve bundles splaying over the tumor surface. Microscopically, the tumors showed a relatively uniform nesting arrangement (Zellballen pattern) of cells and were associated with rich sinusoidal vessels and fibrous stroma. Multiple myelinated nerve fibers were present in stroma and fibrous capsule of the tumor. Sometimes, invasion of nerve trunk by tumor cells was seen. Immunohistochemically, the tumor cells showed diffuse positivity for chromogranin A, neuron-specific enolase and synaptophysin. There was no expression of cytokeratin. The sustentacular cells and nerve bundles were highlighted by S-100 protein.

In addition to the microscopic accurate diagnosis of paraganglioma, histopathologists can be of help in deducing the vagal origin of this tumor.