The management of head-and-neck paragangliomas

Abstract

Paragangliomas (PGLs) are tumours originating from neural crest-derived cells situated in the region of the autonomic nervous system ganglia. Head-and-neck PGLs (HNPGLs) originate from the sympathetic and parasympathetic paraganglia, most frequently from the carotid bodies and jugular, tympanic and vagal paraganglia, and are usually non-catecholamine secreting. Familial PGLs are considered to be rare, but recently genetic syndromes including multiple PGLs and/or phaeochromocytomas have been more thoroughly characterised. Nowadays, genetic screening for the genes frequently implicated in both familial and sporadic cases is routinely being recommended. HNPGLs are mostly benign, generally slow-growing tumours. Continuous growth leads to the involvement of adjacent neurovascular structures with increased morbidity rates and treatment-related complications. Optimal management mostly depends on tumour location, local involvement of neurovascular structures, estimated malignancy risk, patient age and general health. Surgery is the only treatment option offering the chance of cure but with significant morbidity rates, so a more conservative approach is usually considered, especially in the more difficult cases. Radiotherapy (fractionated or stereotactic radiosurgery) leads to tumour growth arrest and symptomatic improvement in the short term in many cases, but the longterm consequences are unclear. Early detection is essential in order to increase the chance of cure with a lower morbidity rate. The constant improvement in diagnostic imaging, surgical and radiation techniques has led to a safer management of these tumours, but there are still many therapeutic challenges, and no treatment algorithm has been agreed upon until now. The management of HNPGLs requires a multidisciplinary effort addressing the genetic, surgical, radiotherapeutic, oncological, neurological and endocrinological implications. Further progress in the understanding of their pathogenesis will lead to more effective screening and earlier diagnosis, both critical to successful treatment.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Paragangliomas

“…Genetically, mutations in the SDHx family of genes accounted for all of the hereditary cases in one series (89% with SDHD, 8% with SDHB, and 1% with SDHC) [41] though rare SDHAF2 have also been documented [42]. The metastatic rate may be higher for vagal PGL than other sites, 16% versus 2-6% for carotid body and middle ear PGL, with lymph nodes involvement accounting for the majority of cases [43,44]. Further studies to clarify this rate are still needed, as multifocal PGL (second primary PGLs) versus true metastasis was not always excluded.…”

“…Clinical presentation at this site includes possible palpable neck mass, or uncommonly neuropathies, however most patients are asymptomatic with detection on imaging studies. Multicentric presentation occurs in ~1/3rd of cases with the vast majority (80%) of these having a documented family history of PGLs [40]. Anatomically the vagal nerve runs near the carotid bifurcation, thus careful evaluation of the relationship of the mass to the carotid bifurcation/ carotid body region by imaging allows for this distinction.…”

Head and Neck Paraganglioma: Medical Assessment, Management, and Literature Update

“…The goal of radiotherapy is to reduce tumour size and to halt/control growth. Radiotherapy via external beam radiotherapy or stereotactic radiosurgery has shown excellent local control rates (>95%) for primary management in HNPGL [57][58][59]. Radiotherapy is not without complications; the major being failure to control the tumour [58].…”

“…Familial HNPGL are more likely to be recurrent, or multiple in nature and close post-treatment follow-up is advised. Although there is no acknowledged protocol for long-term follow-up, surveillance examination and imaging every 1-2 years is advocated [59].…”

“…nature and close post-treatment follow-up is advised. Although there is no acknowledged protocol for long-term follow-up, surveillance examination and imaging every 1-2 years is advocated [59]. Based on the literature and our experience, a proposed algorithm for assessment of a patient with HNPGL suspicious for a hereditary form is presented in Figure 4.…”