BACKGROUND: Crowned dens syndrome (CDS) is a clinical-radiological entity 
characterized by acute attacks of neck pain with fever, rigidity, general signs 
of inflammation, and calcification of the periodontoid articular structures.
METHODS: Case report with 42 months follow-up.
CASE DESCRIPTION: An 81-year-old man, who had never suffered from headache 
before July 2010, developed strictly left-sided headaches. The pain was 
restricted to the left side of the scalp and felt more intense in the frontal 
area. The intensity was moderate to high with a throbbing quality. The pain had 
an orthostatic component and was worsened by neck hyperextension and Valsalva 
maneuvers. Neurological and general examinations were normal, except for a 
reduced range of motion of the neck. He was prescribed indomethacin orally 25 mg 
t.i.d. and had a partial response. After a week, he was given a dosage of 50 mg 
t.i.d. with complete remission of the pain. Brain magnetic resonance imaging was 
normal, while an magnetic resonance imaging of the cervical spine showed a 
non-homogeneous mass behind the odontoid process of C2, narrowing the 
subarachnoid space in C1, stretching the posterior longitudinal ligament, and 
touching the left vertebral artery. A computed tomography scan showed 
calcification of the soft tissue around the odontoid process and a thickening of 
the left C2 root. After 4 months, the indomethacin dosage was reduced 
step-by-step. Indomethacin was discontinued in March 2012. Since then, the 
headache has not recurred.
DISCUSSION: We here present the case of a patient with headache and radiological 
findings of crowned dens. However, the clinical presentation differed from 
previous CDS cases in the literature in that the pain was unilateral with 
frontal localization and throbbing quality, as well as an orthostatic component 
and lack of either fever or inflammatory signs. The differential diagnosis also 
includes a remitting form of hemicrania continua, presenting with an atypical 
presentation, with neuroimaging incidental finding of CDS.
CONCLUSION: This case widens the spectrum of the clinical presentation of 
crowned dens, a condition that should be kept in mind in cases of unilateral 
headache in older patients.