Hemicord White Matter Enhancement and the Croissant Sign in Cervical Spondylotic Myelopathy

Approximately 7% of cervical spondylotic myelopathies (CSMs) have enhancement often leading to misdiagnosis as tumor or myelitis.1,2 A sagittal transverse flat pancake-like enhancement just below the maximally stenotic region with axial circumferential white-matter enhancement is characteristic.2 In our CSM with enhancement database (January 1, 1996-January 5, 2023), 16 patients (14%) had unilateral hemicord (right, 8; left, 8) white-matter enhancement sparing gray matter resembling a "croissant" (Figure 1). The median age was 52 years (range 24-74 years), 75% were male, and they had an insidious (n = 12) or subacute (n = 4) myelopathy (asymmetric, 12 [6 with Brown-Sequard syndrome localizing to the side of enhancement]; symmetric, 4). Four patients (25%) had the reverse Lhermitte phenomenon with neck extension. The maximum compression was often contralateral to the enhancement on available preoperative images (n = 14: contralateral, 5; middle, 6; ipsilateral, 3) and could take years to resolve after surgery (Figure 2).2 Hemicord enhancement with an axial croissant sign should raise suspicion for CSM.