Demonstration of scolex within calcified cysticercus cyst: its possible role in the pathogenesis of perilesional edema.

PURPOSE

This study was performed to understand the relation between the scolex as demonstrated on gradient echo (GRE) imaging in a calcified cysticercus cyst and the development of perilesional edema that may be of value in understanding the pathogenesis of this entity.

METHODS

Twenty-one patients with solitary calcified lesion on computed tomography (CT), with seizures of recent onset (within 15 days), were selected for this study. All the patients were subjected to magnetic resonance imaging (MRI) including GRE imaging. The patients were grouped on the basis of presence or absence of perilesional edema around the calcified lesion on MRI.

RESULTS

There were 14 patients with perilesional edema, and seven patients had no evidence of edema. Of these 14 patients with perilesional edema, rim enhancement was detected in 13 patients on postcontrast MRI, whereas no enhancement was observed in one patient. The scolex was seen in all these 14 patients on GRE images. Of the seven patients without evidence of edema, the scolex was not seen in any of these patients on GRE imaging. In addition, there was no evidence of any contrast enhancement on postcontrast study in any of the patients in this group.

CONCLUSIONS

We conclude that the calcified cysts with scolex seen on GRE imaging are associated with perilesional edema. This is probably due to preservation of antigenic material in these calcified cysts, the release of which provokes an inflammatory response that may be responsible for the perilesional edema.