[Acute, hyperintense, and febrile cervicalgia. Crowned dens syndrome, a monofocal microcrystalline arthritis sometimes doubly misleading].

Microcrystalline arthritis sometimes have atypical localizations and presentations. The crowned dens syndrome, due to hydroxyapatite or calcium pyrophosphate deposits in peri-odontoid ligaments of the atlas, can provoke acute or chronic cervicalgia or misleading presentations such as meningitidis or fever of unknown origin. We present a particularly severe new case requesting urgent surgery, and a literature review to alert clinicians and prevent misdiagnosing this syndrome. Indeed, calcifications may be very discrete or just incidental and prevent a complete diagnostic approach.