Paragangliomas of the Head and Neck: A Review of the Latest Diagnostic and Treatment Methods.

ABSTRACT

Background and objectives: Paragangliomas of the head and neck are rare, slow-growing neuroendocrine tumors, benign in their vast majority, but with a possibility of developing distant metastases. They show great inheritable character, and their behavior has proven to be unpredictable; therefore, they are considered malignant. Material and methods: This article aims to offer a more comprehensive presentation of the pathogenesis, epidemiology, diagnostic methods, imaging development, and treatment guidelines. We tried to bring together all the necessary data that, in our opinion, a head and neck practitioner should know when managing this type of tumor. Our main focus is on the most recent studies, with the purpose of a homogenous presentation of all current guidelines and approaches to this pathology. Results: Paragangliomas of the head and neck are still a disputed topic. One of the main reasons for that is their low incidence of 0.3 to 1 per 100,000 every year. The most frequent locations are the carotid body, the temporal bone, the jugular and mastoid foramen, and the vagal nerve. Their clinical presentation usually involves a painless lateral mass associated with symptoms such as hoarseness, hearing loss, tinnitus, and cranial nerve deficits. Up to 40% of them are inherited, mostly linked with mutations of succinate dehydrogenase complex. Imaging evaluation consists of CT and MRI, and new functional explorations such as 18F-FDA and 18F-FDG PET/CT, 18F-DOPA PET, 123I-MIBG, and 68Ga-DOTATE PET/CT. Measuring the catecholamine levels in the plasma and urine is mandatory, even though paragangliomas of the head and neck rarely display secretory behavior. Treatment mainly consists of surgery, with different approaches and techniques, but conservative management methods such as wait and scan, radiotherapy, proton therapy, and chemotherapy have proven their efficiency. The therapeutical decision lacks consensus, and current studies tend to recommend an individualized approach. Guidelines regarding long-term follow-up are still a matter of debate.