Hydatid infestation of the brain: difficulties with computed tomography diagnosis and surgical treatment.

The radiological, surgical and pharmacological management of 11 children with cerebral hydatid disease is presented with special emphasis on the varying CT and MRI appearances and the surgical difficulties we have encountered. All but 2 had enhanced CT scanning and 2 had an MRI. The typical CT appearance of a large non-enhancing cyst of CSF density with minimal oedema was only seen in 3 children. Atypical appearances included irregularity of the cyst wall contour (2), enhancement of the surrounding rim (3), isodensity or heterogeneity of the cyst content (4), surrounding oedema (4) and globular as opposed to curvilinear calcification (2). Complete intact cyst removal was achieved in 3 patients. The reasons for puncturing the cysts or rupturing them at operation were failure to make a definitive pre-operative diagnosis (5), dense adhesions to the skull, dura or falx (3) and the misdiagnosis of an arachnoid cyst and the subsequent placement of a cystoperitoneal shunt (1). Pathological examination suggests that the degree of the inflammatory response to the ectocyst may determine the enhancement characteristics and the ease of surgical removal. There was 1 recurrence which responded well to four 28-day treatment cycles of albendazole.