Hydatid Cyst of the Brain and Its Treatment

ECHINOCOCCIJS YST of the brain is not encountered as frequently in Greece as it is in some other countries where this condition is prevalent. This may be due to failure to recognize the condition, since the neurosurgical service has only recently been organized here. To date 14 cases have been reported from Greece by Patrikios, Coccalis, Carajanopoulos, Sbarounis, Heliades, and Deconomou, and eight cases have been operated upon in the clinic of Maccas. Since 1951 the author has performed 44 1 intracranial operations, including five hydatid cysts, or 1.1 per cent. In this series there were 305 cases of brain tumor; thus 1.6 per cent of these were hydatid cysts. Three other cases were seen during the period from 1935 to 1942. One of the reasons why echinococcus cysts are so rare in the central nervous system is that the larvae have difficulty in passing through the capillaries of the liver and the lungs. In fact, since these capillaries serve as a filter which removes these organisms from the circulation, the liver and lungs serve as the most common sites for this disease. Of course, it must be recognized that occasionally the organism may bypass the lungs and reach the brain by way of a patent foramen ovale in the interauricular septum. In other instances, a cyst may rupture in the lung, emptying many scolices into a pulmonary vein. These may then be transported to the brain as well as elsewhere in the body. Another possibility to be considered is the rupture of a primary cyst in the left side of the heart. Such ruptures occur most frequently in children and result in multiple cysts in the brain and in other organs of the body. Figure 1 shows typical multiple cysts within the brain, but in this case necropsy failed to reveal any primary cyst in the heart or any other organ. Usually echinococcus cysts in the brain are single, but due to the soft non-resistant character of brain tissue they are usually large. Secondary or daughter cysts result from rupture of the primarv cyst. This may result from injury to the skull. In one case, in addition to the main cyst in the brain, we found numerous daughter cysts between the dura mater and the bone. These we attributed to injury which caused a rupture of the primary cyst attached to the dura mater. The cysts within the brain typically have thin walls and are devoid of villi. However, in one of our cases, the wall was very thick and the inner surface contained islets of villi. This abnormality was of the type which DCvC called CutilBme or ChitonBme. We are indebted to Professor Coutelen whose investigation established the nature of the unusual cyst in our case. He demonstrated the thick, porous wall with islets of villi at intervals upon its inner surface (figure 2). Echinococcus cysts do not invade the brain but only compress it. The brain, in turn, usually develops a thin gliotic membrane about the cyst, but this is not a true capsule. Hydatid cysts are much more common in children than in adults. This probably results from the fact that children associate more closely with dogs and are not aware of the importance of hygienic and sanitary principles. Seven of our eight cases were children under age ten. The only adult was 45 years old. The two most common complications of hydatid cysts are 1) secondary infection and 2) rupture of the primary cyst into the subarachnoid spaces or the ventricles with widespread dissemination of the infestation. In our experience echinococcus cysts occur most frequently in the parieto-occipital region. Such was the location in five of our eight cases. The others were in the frontal and frontoparietal regions of the cerebrum or in the posterior fossa. The clinical picture develops slowly and resembles that of a cystic astrocytoma. Usually the general health of the patient is good and evidence of hydatid cysts elsewhere in the body is uncommon. The most conspicuous symptoms are those of increased intracranial pressure. In children this includes enlargement of the head. Localizing manifestations are mainly hemiplegia and sensory and visual disturbances. Unfortunately, many of these patients lose their vision before the condition is recognized and relieved. Trembling of the extremities may occur and many of our patients suffered from convulsions. The differential diagnosis is not easily made, particularly in adults where these cysts are usually mistaken for neoplasms. In children