Cervical Paraganglioma

Diagnosis Definition

• Cervical paragangliomas (aka glomus tumors)  are derived from neuroendocrine cells of parasympathetic tissue (although intra-abdominal paragangliomas and pheochromocytomas arise from sympathetic tissue)
• There are four main types that occur in the extracranial head and neck: glomus jugulare, glomus jugulotympanicum, glomus tympanicum, or carotid body tumor
• They are not usually associated with endocrinopathies
• Patients usually present with single or multiple palpable masses, pulsatile tinnitus, or neurologic deficits related to mass effect
• About 25% of cervical paragangliomas arise in the setting of a heritable syndrome, including Multiple Endocrine Neoplasia (MEN 2A or 2B), von Hippel-Lindau, Neurofibromatosis type1, and the Carney Triad (chondromas of the lung, extra-adrenal paragangliomas, and gastrointestinal stromal tumors)

Imaging Findings

• Cervical paragangliomas are typically hyperenhancing masses on both CT and MR in classic locations: carotid space, jugular foramen, middle ear, and along the course of the vagus nerve
• Classically, T1 MR images show black flow voids and bright foci of slow flow or hemorrhage, creating a “salt and pepper” appearance
• On T2 images, cervical paragangliomas are hyperintense to skeletal muscle

KEY IMAGES

Pearls

• Cervical paragangliomas can be multiple, particularly in the setting of a known syndrome; PET scanning with Dotatate and Dotanoc can be performed if further characterization is warranted
• Cervical paragangliomas should not be biopsied due to the risk of exsanguination; pre-operative embolization is commonly performed to reduce perioperative blood loss
• The differential diagnosis for carotid space masses includes nerve sheath tumors, pathologic lymph nodes (infectious and neoplastic processes), aneurysms or other vascular anomalies and meningiomas

References

1. Kirmani S, Young WF. Hereditary Paraganglioma-pheochromocytoma syndromes. Gene Reviews 2014; available at https://www.ncbi.nlm.nih.gov/books/NBK1548/.  Accessed 10/17/2019
2. Chengazi HU, Bhatt AA. Pathology of the carotid Space. Insights into imaging 2019; 10(1):21