Primary and metastatic paraganglioma of the cranial vault

Aim: Primary paragangliomas (PGs) are extra-adrenal neuroendocrine tumours that are extremely rare. Multiple lesions in the central nervous system raise suspicion of a metastatic process. Lack of consensus on their management warrants the categorization of existing literature to evaluate management options.

Methods: A systematic review of the medical literature on paraganglioma within the cranial vault was completed in accordance with PRISMA guidelines using the Medline database. Tumour physical measures, management parameters, and immunohistochemistry of all documented cases of primary and secondary paraganglioma within the cranial vault were descriptively compared. This review was augmented by comparison with our centre's case of a 48-year-old man diagnosed with metastatic PG originating in the cauda equina and seeding in the cerebellum. Histological parameters within the literature was also established.

Results: The systematic literature review yielded published 52 papers. Most prevalent primary intracranial PGs (n = 37) were in the sellar region (78%, n = 23) and the cerebellum (21%, n = 6). The highest progression free survival was seen in primary sellar PGs (87.5% by 34.5 months) and cerebellar PGs (100% by 35.7 months) when treated with adjuvant radiotherapy with subtotal resection or gross total resection, respectively. Contrasting, the most frequent intracranial PGs metastases (n = 15) occurred in the cerebellum (36%, n = 6), and the cerebral parenchyma (29%, n = 4). Their recurrence rate was between 4 and 10% and these metastasized PG in the cerebellum are slow growing (8.9 years, range: 3-22 years). Adjuvant radiotherapy with Gross Total Resection resulted in the optimum progression-free survival (100% up to 48 months) for the patient with PGs metastasis to the cerebellum.

Conclusion: Metastatic PGs tend to be slow-growing and are clinically silent tumours. Diagnosed patients should undergo regular surveillance neuroradiological assessment, regardless of symptomatology, for metastases along the complete neural axis. We recommend operative management with GTR and adjunct RT in these patients.