Glomus vagale tumour, can it be diagnosed only on sonography?

ABSTRACT

Vagal paragangliomas are rare benign tumors accounting for only 3% of head and neck paragangliomas and arise from vagal ganglions, predominately the nodose ganglion in the carotid sheath. Imaging plays an important role in their diagnosis, differentiation from more common lesions presenting in the carotid space, and management. MRI is the method of choice for investigation when paragangliomas are clinically suspected. The typical salt-and-pepper appearance in T1-weighted images is well known but not specific to paragangliomas. Demonstration of the continuity of the lesion with the vagus nerve on magnetic resonance imaging (MRI) further asserts the diagnosis of glomus vagale. Although this tumor can be diagnosed on a contrast-enhanced computed tomography (CECT) examination, it is limited by the non-demonstration of its neural origin. Sonography is considered only a preliminary investigation in patients, and a CECT and/or MRI study of the neck is conducted before treatment planning. This case is unique as a confident diagnosis of glomus vagale was made on high-resolution sonography of the neck. A middle-aged male patient presenting with a neck swelling was diagnosed with a glomus vagale tumor on USG by the direct demonstration of its continuity with the vagus nerve, and Doppler examination confirmed its vascularity. The diagnosis was confirmed on histopathology after surgical excision. The sonographic appearance, Doppler characteristics, and imaging differential diagnosis of glomus vagale are discussed in detail.