seroprevalence of hydatidosis is between 1.2 and 13.8% in the different region of iran ( 1 ) .
brain involvement occurs in 12% of patients with hydatidosis and comprises 2% of all brain masses in the endemic region , especially among the children ( 2 ) .
symptoms of the brain hydatid cyst vary by location and size of the cyst . in a retrospective study of 117 children in tunis ,
common symptoms were a headache , vomiting , hemiparesis , seizure , mood alteration , and skull deformity ( 3 ) .
more than 50% of patients with the brain hydatid cyst have multiple cysts in the brain , and about 18% have visceral involvement , which has 9% mortality rate ( 4 ) . surgical treatment and excision of the cyst
ruptures of the cyst and anaphylactic reaction are the most frequent complication of the surgery with the prevalence of 10% . here
we present an adult male with a large brain hydatidosis and atypical symptoms , who was treated successfully by surgery .
a 19 yr - old male livings in ardabil , northwest of iran , was referred to neurosurgery clinic in khanevadeh university hospital , tehran , iran for a headache and progressive left hemiparesis since a week ago .
he was treating for depression and incuriosity for two months by a psychologist . during two weeks
, he developed headache , vomiting , and in the last week , left - side paraparesis occurred .
peripheral neurological examination showed left hemiparesis with the force of three to fifth in all muscle groups and normal deep tendon reflexes .
brain contrast - enhancing magnetic resonance imaging ( mri ) showed a large round mass about eight centimeters in the right frontoparietal lobe and mildly shifting the cerebral hemisphere to the left , without any ring - enhancement or surrounding edema ( fig .
1 ) . contrast - enhanced t1-weighted brain mri shows a large brain hydatic cyst in the right frontoparietal lobe with mildly shifting of the cerebral hemisphere laboratory results showed mild anemia ( hemoglobin=13.1 milligrams per deciliter ) .
further laboratory and imaging findings were normal , except for antibody titer against echinococcosis , which raised fourfold above - normal range in igg .
oral treatment with albendazole at a dose of 400 mg twice daily was initiated , and the patient underwent surgical excision of the cyst .
right craniotomy through parietal bone with left side , head turning position was done under general anesthesia . a largely fluctuated mass with adhesion to surrounding tissue appeared after dural opening , and 3% warm saline infused around the mass during 30 min , which led to slowing delivery of the mass in the next 40 min ( fig .
2 ) . surgical excision of the brain hydatic cyst via right craniotomy through parietal bone finally , free layers were sutured anatomically consequence , and the bone fixed by bone - adhesive glue . oral treatment continued about three months .
after one - yr follow - up , left hemiparesis improved , and the left side limbs forces raised to four - fifths . at this time brain mri
cystic hydatid disease ( chd ) is an infectious parasitic disease , often caused by e. granulosus .
this parasite distributes worldwide , and the main routes of transmission are ingestion of foods or water , which is contaminated by scolex or egg .
12% of the patients have cerebral involvement , especially in the parietal lobe ( 2 ) .
brain hydatid cysts may grow up 110 cm a year and symptoms are often related to elevated intracranial pressure ( icp ) and focal neurological deficit ( 5 ) . in our patient ,
symptoms of rising icp appeared in the advanced course of the disease and the main complaints , which resulted in seeking medication , were depressive mood alteration , personality instability , and apathy .
dowling technique is often used for surgical excision , which consists of craniotomy through a big opening hole , cortical dissection and hydrostatically delivery of the cyst using an injection of hypertonic saline ( 3 ) , such as our patient .
ruptures of the cyst and anaphylactic reactions are the most common complication of the surgery , but other complications such as subdural effusion , hematoma , pneumocephalus or herniation must be considered ( 6 ) .
emergent brain surgery was performed in a 13 yr - old male for cerebral herniation because of a massive brain hydatid cyst ( 5 ) . despite the significant size of the cyst and adhesion to surrounding tissue in our patient , he did not experience any complication .
it seems that other related factors such as adhesion to surrounding tissue , the severity of intracranial pressure , access to the operative field , and expertness of the surgeon may influence the outcome .
we believe that the best surgical technique for excision of the cyst is adequate craniotomy , gentle decortication and enough time spending during the surgery .
 brain hydatid cyst constitutes one of the leading causes of cranial mass in the endemic region , especially among the children . 
 symptoms of the disease are associated with rising of intracranial pressure and focal neurological deficit . 
 surgical excision of the cyst is essential to treatment . here 
 we present a 19 yr - old male livings in ardabil , northwest of iran , referred to neurosurgery clinic in khanevadeh university hospital , tehran , iran with a large brain hydatid cyst and atypical symptoms . 
 he was treated by surgical excision of the cyst without any complication . 
 there were not any clinical or radiological signs of recurrence after one - year follow - up . 