[Unusual manifestation of cerebral cysticercosis]

We have surgically treated two patients with cerebral cysticercosis, which were pre-operatively unexpected due to unusual CT and MRI manifestations. A 24 year old chinese farmer with intermittent severe headache for 6 years was examined by CT and MRI. A huge cystic lesion with same density or intensities to CSF occupied retroclival posterior fossa to upper cervical spinal canal and displaced neural structures backwardly. By suboccipital craniectomy, watery clear cyst fluid of 44ml was aspirated and the shrunken cyst was pulled out with ease. It was unable to predict until an electron microscopic study, which revealed a larva with three layers of microvilli, vesicular tegmentum and infrategmental muscle bundles and vesicles. The findings were same to those of racemose cysticercus of human brain. Giant cysts of cysticercosis were infrequently present supratentorially, although infratentorial or basal cysticercosis were racemose and small. The present case may be the first case of a huge cyst of cysticercosis in posterior fossa. A 44 year old Japanese businessman with 15 years history of general convulsion underwent craniotomy due to a small, but growing cystic granulomatous mass in right inferior frontal gyrus. The CT scan examined at 3 years after his first general convulsion revealed a small round low density mass, 5mm in diameter, in right frontal lobe and its wall was weakly enhanced by contrast media. The follow-up CT scans and MRIs revealed that the enhancing cystic mass became thick and deformed, and perifocal edema came to evident and progressed stepwise by attacks of general convulsions.(ABSTRACT TRUNCATED AT 250 WORDS)