Single parenchymal brain cysticercus: relationship between age of patients and evolutive stage of parasites

Background: A recent hypothesis suggested that in many cases cysticercal granulomas represent recently established Taenia solium metacestodes rapidly destroyed by the host's immune system. Here, we attempted to determine whether patients with cysticercal granulomas are younger than those with other forms of parenchymal brain cysticercosis. Methods: Series of 185 patients with single parenchymal brain cysticercus, classified according to the stage of the parasite at the moment of diagnosis in cysts without inflammation, cysts with inflammation, granular lesions, and calcifications. We correlated the age of the patients with the parasite evolutive stage. Results: Patients with cysticercus granulomas were significantly younger than those with vesicular cysts (17.7 +/- 12.9 versus 36.8 +/- 15.1 years, P < 0.005) or calcifications (17.7 +/- 12.9 versus 40.8 +/- 19.7 years, P < 0.0001). There was also a non-significant trend for patients with granulomas to be younger than those with coloidal cysts (17.7 +/- 12.9 versus 26.7 +/- 15.6 years, P=0.367). Conclusions: Results from this study argued against the classical hypothesis that granulomas are the end result from long-established vesicular cysts destroyed by the host's immune system. Vesicular (viable) cysticerci must be treated with cysticidal drugs as it is unlikely that they will be spontaneously destroyed.