A series of 50 patients with a total of 164 episodes of pseudomigraine with temporary neurologic symptoms and CSF lymphocytic pleocytosis (PMP syndrome) is reported from the University Hospital Marques de Valdecilla, Santander, Spain. Onset was between 14 and 39 years, 68% in males. About one third had a past history of migraine, and one-quarter had a viral-like illness within 3 weeks of onset. A throbbing, bilateral headache lasting an average of 19 hours was associated with unilateral sensory symptoms (78% of episodes) of mean duration 5 hours, aphasic (66%) and motor (56%) symptoms, and visual symptoms in only 12% of episodes. Lymphocytic pleocytosis was 10 to 760 cells/mm3 (mean, 199). CSF protein was increased. Viral studies were negative. EEG showed focal slowing. Angiography in 12 patients was normal except one showing localized vasculitis. An aseptic inflammation of leptomeningeal vasculature is suggested as a possible cause. 
COMMENT. This appears to be the largest series of patients reported with the syndrome of transient headache and CSF lymphocytosis. A previous report of 7 patients and review of 33 cases in the literature, 13 in children and adolescents, were included in Ped Neur Briefs, Oct 1995 (see Progress in Pediatric Neurology III, 1997;pl78). The differential diagnoses listed by the authors (Berg MJ, Williams LS) included Lyme neuroborreliosis, neurosyphilis, neurobrucellosis, neoplastic meningitis, HIV meningitis, hemiplegic migraine, seizures, Mollaret’s meningitis, and a side effect of angiography. The syndrome is self limited, and a viral etiology appears plausible.