Calcifying Pseudoneoplasm of the Neuraxis: A Case Illustrating Natural History over 17 Years of Radiologic Surveillance

Background: Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare central nervous system lesion that can occur in both the brain and the spine. Although this entity is poorly understood, radiologic and histological features have been identified. Case Description: We report a unique case of a 31-year-old patient who was managed with antiepileptic medication for 17 years before requiring neurosurgical intervention for tumor progression. T2-weighted magnetic resonance imaging revealed hyperintensity within the tumor with extensive associated vasogenic edema, which is not normally associated with CAPNON. Resection was successful with no complications. Conclusions: The present case illustrates the long-term natural history of CAPNON before resection and highlights the variations in radiologic appearance that may be associated with this poorly understood entity.