Background: Parasites have been implicated in the pathogenesis of huma
n cancer. Anecdotal reports have suggested an association between neur
ocysticercosis and brain tumors. Objective: To determine whether neuro
cysticercosis is a risk factor for cerebral glioma. Design: Case-contr
ol study. Setting: A university general hospital and a cancer referral
center. Patients: Forty-three consecutive patients with a cerebral gl
ioma and 172 controls matched for age, sex, and socioeconomic status.
Methods: We determined the ratio between the frequency of neurocystice
rcosis in patients with a cerebral glioma and in matched controls. We
also evaluated differences in the characteristics of the patients and
in the histological type of the neoplasm among case patients with and
without neurocysticercosis. In addition, we noted relationships betwee
n the location of the cerebral glioma and that of parasitic lesions. R
esults: Eight (16.8%) of 43 patients with a glioma and 5 (2.9%) of 172
controls had neurocysticercosis (P<.001). The odds ratio for this ass
ociation was 7.63 (95% confidence interval, 2.03-31.09). Patients with
glioma and neurocysticercosis were older than those without neurocyst
icercosis (mean [+/-SD] age, 62.75+/-18.34 years vs 44.69+/-14.04 year
s; P=.02). Glioblastoma multiforme was more frequent among case patien
ts with neurocysticercosis than among those without neurocysticercosis
(87.5% vs 48.6%); however, this difference was not statistically sign
ificant (P=.24). Six of the 8 patients with neurocysticercosis and a c
erebral glioma had calcified parasitic lesions within and around the t
umor. Conclusions: Results from this study suggest that neurocysticerc
osis is a risk factor for cerebral glioma. The intense astrocytic glio
sis that surrounds calcified cysticerci, together with the suppression
of the cellular immune response induced by cysticerci, may contribute
to the development of malignant glial cells in patients with neurocys
ticercosis.