bloc excision is mandatory but can represents a real technical challenge , expecially if tumor involves both the skull and the dura .
the term primary intraosseous meningioma ( pim ) is used for an extradural meningioma that arises from the cap cells staying in the bone .
they are mostly met at the periorbital and frontoparietal regions   and they are , generally , devoid of neurological findings .
other tumors that can involve the skull are hemangiomas , metastases , many type of carcinoma and sarcoma arising directly by bone or by contiguous tissue ( cutis , muscle , dura ) and invading secondarily the skull .
the degree of resection is the most important factor correlating with recurrence and clinical long - term outcome .
the aggressive surgery that is needed in these cases could bring a large bone defects to fill .
the removal of a tumor involving the skull and the intracranial space could present a technical challenge , especially if the tumor has a dural and/or brain attachment . with a standard craniotomy , the maneuver of separating the intraosseus portion of the tumor from the intracranial portion might produce hemorrhage , traction and injury to the underlying brain .
we describe a technique where the tumor involving the bone is before left in situ , normal dura is exposed around the tumor , and the tumor can be afterwards removed en bloc with direct vision and minimally traction of the brain surface .
8 patients , with different tumors involving both skull and dura , were treated with these technique .
the histological examination of these patient s specimens showed : atypical meningioma , pim and anaplastic meningioma .
below , we describe this technique used in the last patient treated , a man aged 45 with no neurological signs .
patient underwent dcc , total surgical excision of pim and cranioplasty with peek custom made prothesis ( synthes ) . a 45 years old man , b.v .
, presented to our department of neurosurgery with a mass arising from the right frontoparietal bone .
he had not neurological signs and symptoms . computed tomography ( ct ) scan showed a homogeneous expansive bone lesion at the right fronto - parietal region , without contrast enhancement . on magnetic resonance imaging ( mri ) ,
the lesion was hypointense on t1- and t2-weighted images with no contrast enhancement after intravenous gadolinium administration , but contrast enhancement was seen at the adjacent dura . in the differential diagnosis , were first considered a fibrous dysplasia and primary bone tumors .
patient undergoes tumor removal and cranioplasty with peek custom made prothesis ( synthes ) . under general anesthesia ,
the patient was positioned with the head turned approximately 30 toward the contralateral side , to expose the skull mass , with a pillow under the ipsilateral shoulder .
the temporal muscle was splitted , the muscolar part that covering the tumor was left in situ for a completely radical resection and the remaining part was overturned .
one only burr hole was performed laterally to the midline and we performed the first circle craniotomy around the lesion .
then , using the same burr hole , a second and more enlarged circular concentric craniotomy was performed .
there was no tumor in the bone ring and the dura beneath the ring was not involved .
the inner surface of the dura was amply involved by the tumor , and it was dissected by the underlying brain surface under direct vision thanks to the space guaranteed by bone ring removal .
the dural defect was repaired with pericardium bovinum patch and a peek custom made cranioplasty was performed ( fig 3 ) .
tumor involving many tissues should be resected en bloc for minimizing risk of seeding and recurrency .
in fact , meningioma with calvarial hyperostosis is commonly associated with an increased rate of recurrence if limited bone resection is performed .
although radical excision of tumor involving the skull is the gold standard of oncological treatment , elevating a bone flap when the tumor involves both the skull and the dura could be very hard and represents a technical challenge . with a standard craniotomy
this maneuver , done without direct vision , could produce hemorrhage and unwanted traction on the underlying brain surface .
we have described a technique , a dcc , that permit to expose the normal dura surrounding the tumor and permit the resection of entire specimen with a direct vision of the underlying brain . in our opinion
also have described a similar procedure for the removal of nail that was hammered in both the skull and the brain .
sekhar et al . have utilized the concentric craniotomy technique for a fronto - orbital approach and ibarra - de la torre et al . for a posterior fossa craniotomy to protect the underlying dura and vascular structures .
we believe that dcc is an optimal alternative on standard technique because permits the total removal of tumor involving both skull and dura structures , minimizing tractions on the underlying brain and permitting the direct vision during the dissection .
 highlightsmany tumors can involve the skull . 
 radical excision is the golden standard of treatment.elevate a bone flap when the tumor involves both the skull and the dura present a technical challenges.double concentric craniotomy is a safe and effective technique to remove tumor involving both skull and dura structures under direct vision . 