Headache caused by carcinomatous meningitis, usually accompanied by signs of encephalopathy and/or cranial nerve palsies.
A. Any headache fulfilling criterion C
B. Carcinomatous meningitis (in the presence of systemic neoplasia known to be associated with carcinomatous meningitis) has been demonstrated
C. Evidence of causation demonstrated by at least two of the following:
1. headache has developed in temporal relation to development of the carcinomatous meningitis
2. either or both of the following:
a) headache has significantly worsened in parallel with worsening of the carcinomatous meningitis
b) headache has significantly improved in parallel with improvement in the carcinomatous meningitis
3. headache is associated with cranial nerve palsies and/or encephalopathy
D. Not better accounted for by another ICHD-3 diagnosis.