ARRS 2022 Abstracts

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E1342. Calcifying Pseudoneoplasms of the Neuraxis: Pictorial Review With Histologic Correlation
Authors
  1. Kenneth Huynh; University of California, Irvine
  2. Ba Nguyen; Mayo Clinic Scottsdale
Background
Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare, non-neoplastic, calcified lesions that can develop anywhere in the neuraxis. The pathogenesis of CAPNON is still to be elucidated; however, reactive and immune-mediated processes have been supported. Detection of CAPNON is typically incidental, with clinical presentations varying from asymptomatic to nonspecific symptomatology relating to mass effect. Diagnosis is typically challenging due to other neural-based entities with similar imaging features. This challenge is further complicated by the association and coexistence of CAPNON with another distinct pathology within the same anatomic location (“collision lesion”), suggesting a reactive pathogenesis of CAPNON. This educational exhibit will help radiologists differentiate CAPNON from other mimicking entities.

Educational Goals / Teaching Points
The goals of this exhibit are to present the epidemiology, pathogenesis, clinical manifestations, and differential diagnosis of CAPNON and to characterize imaging features of CAPNON with histologic correlation and a case-based review of associated mimicking entities.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
This exhibit will present imaging features of CAPNON on CT and MRI. These lesions can occur anywhere in the CNS with no predilection to the brain or the spine. CAPNON will demonstrate dense calcification on CT imaging. T1- and T2-weighted MRI show hypointense lesions with no vasogenic edema and minimal rim enhancement. CAPNON are not FDG-avid lesions and intracranial lesions will show prominent hypometabolism in the setting of physiologic brain uptake. Differential diagnoses include meningioma, oligodendroglioma, cavernous malformation, neurocysticercosis, and hamartomas. This exhibit will discuss a simplified approach to aid in their differential diagnosis.

Conclusion
The viewer will be able to differentiate and distinguish CAPNON from different lesions through a combination of imaging features using multimodality imaging.