Metastatic Esthesioneuroblastoma Recurrence after 19 Years of Remission: A Systematic Review with Case Illustration.

Purpose: Esthesioneuroblastoma (ENB) is a rare malignant neoplasm of the olfactory epithelium with an esti-mated incidence of 0.4/million. It can directly extend along the cribriform plate in order to metastasize to the central nervous system. However, non-contiguous intracranial involvement without recurrence at the primary site is extremely uncommon. In this report, the authors review the literature and present a case of non-contiguous intracranial metastasis of ENB without recurrence at the primary site. To the best of our knowledge, this case presents the longest disease-free interval reported in the literature.Methods: A systematic review of literature was conducted in accordance with the PRISMA guidelines. Addi-tionally, the presentation, surgical management, and post-operative outcomes of an 82-year-old female with non-contiguous intracranial metastasis of ENB after 19 years of remission are described.Results: A total of 137 deduplicated works were identified after the search. Of these, 6 papers satisfied our in-clusion criteria for our systematic review. Average age at presentation was 50.8 years (range: 26-66) and 52.6% of patients were female. A majority of cases achieved gross-total resection and received adjuvant radiotherapy for initial treatment. The median interval to intracranial metastasis was 6 years from the time of primary tumor presentation. The median overall survival from ENB recurrence with non-contiguous intracranial metastasis was 11.5 months.Conclusions: ENB is a highly recurrent tumor and harbors the potential to involve the intracranial space even years after remission. Intracranial involvement entails poor overall survival. Lifetime radiographic follow-up should be considered in all patients with ENB.