title: Occipital Condyle Syndrome: A Red Flag for Malignancy. Comprehensive Literature Review and New Case Report.
abstract: OBJECTIVE
  To perform a literature review of the epidemiology, clinical presentation, diagnostic evaluation, and clinical course of occipital condyle syndrome, including a new case report.
  
  
  BACKGROUND
  Occipital condyle syndrome (OCS) is a rare clinical syndrome, consisting of unilateral occipital headache accompanied by ipsilateral hypoglossal palsy. This headache typically radiates to the temporal region, and is triggered by contralateral head rotation. It is usually associated with skull base metastasis, often unrevealed in basic neuroimaging studies. OCS might be the first manifestation of malignancy, and its unfamiliarity can lead to a delay in the diagnosis.
  
  
  METHODS
  We performed a systematic literature review using PubMed and Embase for OCS, along with a new case report.
  
  
  RESULTS
  A total of 35 cases (mean age 59 years, range 25-77), 24 (70%) men, presented typical unilateral headache followed by ipsilateral hypoglossal palsy from 0 to 150 days after headache presentation. In 16 patients (46%), initial neuroimaging studies were normal. OCS was due to skull base metastasis in 32 cases (91%). In 18 patients (51%), OCS was the first symptom of disease.
  
  
  CONCLUSIONS
  OCS represents a warning sign and requires an exhaustive search for underlying neoplasm. An appropriate clinical evaluation can lead to an earlier diagnosis in patients with consistent headache.
authors.affiliation: La Paz University Hospital, Madrid, Spain.
authors.forename: Jorge
authors.identifier: http://orcid.org/0000-0002-8926-1287
authors.initials: J
authors.lastname: Rodríguez-Pardo
authors.affiliation: La Paz University Hospital, Madrid, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Lara-Lara
authors.affiliation: La Paz University Hospital, Madrid, Spain.
authors.forename: Borja E
authors.initials: BE
authors.lastname: Sanz-Cuesta
authors.affiliation: La Paz University Hospital, Madrid, Spain.
authors.forename: Blanca
authors.initials: B
authors.lastname: Fuentes
authors.affiliation: La Paz University Hospital, Madrid, Spain.
authors.forename: Exuperio
authors.initials: E
authors.lastname: Díez-Tejedor
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006261:Headache / Q000209:etiology*; D006801:Humans; D020437:Hypoglossal Nerve Diseases / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009777:Occipital Bone / Q000503:physiopathology*; D019292:Skull Base Neoplasms / Q000150:complications*
keywords: headache; hypoglossal palsy; occipital condyle syndrome; skull base