Oculomotor compressive neuropathy secondary to calcifying pseudoneoplasm of the neuraxis (CAPNON)

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is an uncommon entity and a rare cause of third cranial nerve palsy. We review the case of a 17-year-old male with a 9-month history of progressive left third cranial nerve palsy. Cerebral magnetic resonance image showed a left clinoidal lesion with low signal intensity in T2 and T1 sequences with signs of calcification in the computed tomography and without vascular lesion in AngioMRI. A left pterional approach was performed with posterior clinoidectomy and total resection of the lesion. Calcifying pseudoneoplasm of the neuraxis is an infrequent pathology that presents in the skull base and spine that requires surgical treatment in the presence of compressive phenomena and differential diagnosis as meningioma, chordoma, and metastasis should be considered.