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Hydatid disease of the breast is not common, but there are undoubtedly more than the approximately 55 cases so far reported. Many cysts are asymptomatic and have no specific local signs. They are found by the patient or physician accidentally as a smooth round mass in the breast. Neither clinically nor on mammography can an intact hydatid cyst in the breast be distinguished from any other benign cystic lesion. Several cases have been diagnosed cytologically after fine needle aspiration of a cyst, a sometimes unexpected result.

The shell-like calcification of a hydatid cyst may mimic a fibroadenoma in the breast. If there are daughter cysts, hydatid sand, or collapsed membranes, the diagnosis can be made by mammography or ultrasound (and also by CT and MRI). When the cyst is complex or multilocular with internal sonographic echoes due to debris, it is difficult to exclude added infection.


Intracerebral hydatids constitute 1 to 4% of all cases of echinococcosis. The cyst is usually primary, developing from a larva carried to the brain via the arterial circulation, and is more often supratentorial than infratentorial in location. A cerebral cyst is generally smaller than a hydatid elsewhere in the body and becomes clinically manifest much earlier in life, because symptoms of increased intracranial pressure from a space-occupying lesion occur relatively early in the disease. Thus, children with an average age of 10 years are the most commonly affected with a primary brain hydatid (Fig. 3.6B). Secondary or metastatic cerebral hydatidosis, however, is seen in an older age group, usually middle-aged adults, similar to the manifestations of the disease in other organs; these metastatic hydatids may result from rupture of a primary cyst within the heart. Implantation of one or more embryos bypassing the liver and lungs is regarded as extremely rare, if not impossible with a normal circulation.

Most cerebral hydatids are in the white matter, usually in the parietal lobe (Fig. 3.118). They are most often solitary, and grow outward toward the cerebral cortex or inward toward the ventricles. Multiple intracranial hydatid cysts are rare and are usually caused by rupture of a single cerebral cyst (after trauma, surgery, or spontaneously) or they may be secondary implants from a ruptured primary extracranial cyst.

Cerebral hydatid cysts can grow rapidly, but the prognosis is better than would be expected, except in very young children. Symptoms such as epilepsy or blindness may occur, depending on the location of the cyst. Calcification of the cyst may occasionally be seen on plain radiographs of the skull (Figs. 3.118B and 3.119), but there is seldom any definitive clue on conventional radiography which will identify the cyst if no calcification is visible.


Fig. 3.118 Hydatid cyst of the brain. (A) Necropsy specimen from an Indian patient with large hydatid cyst in the parietal region of the brain (Courtesy of Dr. A. C. Johnson, Tulsa, Oklahoma.) (B) Large, calcified hydatid cyst of the left cerebral hemisphere in a 20-year-old man. (Courtesy of Dr. William Thomas, McLean, Virginia).


Fig 3.119 Huge calcified hydatid cyst in the right frontal lobe of a patient from India. (A) Lateral view of the skull shows diastasis of the coronal suture; the sella turcica and posterior clinoid processes appear normal. Differential diagnosis would include a large calcified cyst, abscess, solid neoplasm, or even giant aneurysm. (B) Lateral and (C) anteroposterior views of the skull obtained during right carotid arteriography show the large calcified frontal hydatid is causing a shift of the anterior cerebral artery across the midline to the left side and inferior and posterior displacement of the middle cerebral artery. (Courtesy of Dr. A. C. Johnson, Tulsa, Oklahoma).

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