pilocytic astrocytomas ( pas ) , which are most common in children , are world heath organization grade i tumors with a good prognosis .
this neoplasm can occur at all levels of the neuraxis but occurs most frequently in the cerebellum and the optic pathways2 ) .
calcification in pas is not a common finding and is reported more frequently in the optic nerve , hypothalamic / thalamus and superficially located cerebral tumors9 ) .
massive calcification is extremely rare , and the treatment modality for pas is surgery ; the recurrence rate after total excision is very low .
the recurrence time can be as long as four or five years even in the case of residual tumors7 ) . here , we present a case of cerebellar pa with polar spongioblastoma - like cells revealed upon histopathological examination .
this pa had massive calcification and a rapid recurrence rate from the residual tumor that led to re - operation .
a three - year - old male patient presented complaints of vomiting and imbalance that had been present for approximately three months .
a computerized tomography ( ct ) examination revealed 533triventricular hydrocephalus and a left cerebellar mass with hypodense cystic components surrounded by hyperdense area . magnetic resonance imaging ( mri ) revealed a lesion , approximately 64.5 cm in size with cystic central part and peripheral contrast enhancement , which was hypointense on t1-weighted images and heterogeneously enhancing on t2-weighted images ( fig .
the tumor was accessed by left suboccipital craniectomy following an external ventricular drainage catheter being placed in the right lateral ventricle .
the cystic tumor components were evacuated , and the solid part , which had a gray - white color with moderate vascularity and minimal stiffness and could not be clearly distinguished from the normal parenchyma , was excised with the help of an ultrasonic aspirator .
the tumor had a biphasic pattern with pilocytic cells and oligo - like cells in the focal areas ; no necrosis or mitotic figures were observed .
no ema staining was seen , and the tumor cells were diffusely stained positive for gfap . the ki67 index was less than 1% ( fig .
the age of the patient , the localization of the tumor , the lack of mitosis and necrosis that was indicative of high - grade tumors and the focal biphasic and pilocytic features hinted at pa with massive calcifications .
residual calcified areas were found on post - operative ct scans ; no adjuvant therapy was initiated .
post - operative ct and mri at six months revealed growth of calcified tissue , but no contrast enhancement and perfusion increase was observed .
calcified areas were found to have grown more at the 12-month post - operative ct ; areas that showed contrast enhancement were present on the mri ( fig .
macroscopically , the tumor was gray - white in color with moderate vascularity and medium stiffness , and it was totally excised with the help of an ultrasonic aspirator .
a microscopic examination revealed extensive calcification and prominent oligo - like and pilocytic cells as well as the previous tumor .
in addition , polar spongioblastoma - like cells with palisadic sequence were detected in the focal areas .
they are the most common gliomas in children and the majority ( 67% ) tend to be locate in the cerebellum9 ) .
the cystic portion is hypodense on ct , hypointense on t1wi , hyperintense on t2wi , and the solid components are highly enhancinglesions10 ) .
treatment for pas is surgery ; radiotherapy and chemotherapy treatment can be added for tumors that recur and suffer a malignant transformation .
after the total excision of pas , the 10-year survey is 94% , and the 20-year survey is 79%10 ) .
rosenthal fibers and bipolar cells constitute the compact part ; loose array multipolar cells , microcysts and granular bodies constitute the biphasic view10 ) .
oligo - like cells rarely have mitosis , hyperchromatic cells , pleomorphism , glomeruloid vascular proliferation and leptomeningeal infiltration , but they do not indicate malignancy110 ) . diffuse astrocytomas , ganglion cell tumors and pleomorphic xanthoastrocytomas are present in the morphological differential diagnosis of pas . a pilocytic appearance , a biphasic pattern , rosenthal fibers and eosinophilic granular bodies are important in the differential diagnosis .
however , none of these features are characteristic of pas . in cases with prominent glomeruloid vascular proliferation
the presence of marked oligo - like cells , as in our case , can lead to confusion with oligodendriogliomas .
age , radiological appearance and the presence of the pilocytic pattern , even focal , are important for differential diagnosis . the term " primitive polar spongioblastoma " is used for tumors not included in the new who classification and composed of cells with a specific palisading sequence .
this pattern can be seen in pas ( e.g. , the second resection specimen of our patient)4 ) .
tihan and burger13 ) have defined pilomixoid astrocytoma , which is an aggressive subtype of pas .
pilomyxoid astrocytoma is typically seen in early childhood ; most cases settle in the chiasm and hypothalamic region and metastasis through recurrence and cerebrospinal fluid is high .
the reduced metabolism of degenerative tissue stops carbon dioxide production , and the lesion becomes more alkaline than the surrounding tissues as a result .
additionally , increased alkaline phosphatase in degenerative tissues leads to pathologic mineralization such as dystrophic calcification9 ) .
up to 25% of pas have intratumoral calcification6 ) . three intraventricular pa cases with massive calcification
have been reported in the literature , but no case involving the cerebellar region has been published911 ) .
massive calcified pa cases in the literature include patients ages 7 , 15 , and 58 years ; our case involved a 3 year old , which we believe is an early age for massive calcification . in our patient ,
the residual calcified areas began to grow in the third month ; cystic and contrast - enhancing solid components with giant calcification emerged again at the end of the patient 's first year . normally ; calcification and recurrence development can take long period of time .
it takes 45 years for recurrence to occur even after partial resection , which is interesting in terms of a pathology such as pa .
as a result , extensive massive calcification is not a common feature of pas , and it can lead to difficulties in radiological and pathological differential diagnoses .
the gross total excision of pas , including calcified areas , is important to prevent recurrence .
 pilocytic astrocytomas ( pas ) are world heath organization grade i tumors and are most common in children . 
 pa calcification is not a common finding and has been reported more frequently in the optic nerve , hypothalamic / thalamus and superficially located cerebral tumors . 
 we present a cerebellar pa in a 3-year - old male patient with cystic components and massive calcification areas . 
 the residual tumor grew rapidly after the first operation , and the patient was operated on again . 
 a histopathological examination revealed polar spongioblastoma - like cells . 
 massive calcification is not a common feature in pas and can lead to difficulties in radiological and pathological differential diagnoses . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION