petrous bone cholesteatomas ( pbcs ) are epidermoid cysts , which have developed in the petrous portion of the temporal bone and may be congenital or acquired.1 
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 3 the incidence of pbcs was estimated as accounting for between 4 and 9% of all petrous bone lesions.1 
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  a pbc gradually invades the bony labyrinth and erodes the petrous apex and the skull base around the internal auditory canal ( iac ) and may extend as far as the cerebellopontine angle .
furthermore , these lesions may affect other vital soft tissue structures within the temporal bone such as the sigmoid sinus or the jugular vein and carotid artery.1 
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  as regard the source and extension of cholesteatomas , sanna et al1 classified five types of pbc lesion : supralabyrinthine , infralabyrinthine , massive labyrinthine , infralabyrinthine 
lateral transtemporal or middle fossa approaches by microscopic surgery are usually employed for removing extensive pbcs.1 
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  in recent years , the instrumentation , techniques , and knowledge relating to middle ear endoscopic surgery have greatly improved . at present , the main application of endoscopic surgery is in the surgical treatment of middle ear cholesteatoma , but the natural evolution of the technique may provide an increasing number of applications in lateral skull base surgery.9 
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  this case report illustrates the case of a giant cholesteatoma that eroded the labyrinth and the posterior fossa dura and extended to the infralabyrinthine region , thereby affecting the body of the first cervical vertebra .
few authors have dealt with the topic of a pbc , which presents this type of massive life - threatening infralabyrinthine extension , and there is apparently no literature documenting cases in which a cholesteatoma has extended to the extracranial area and cervical spine .
we performed an infralabyrinthine subtotal petrosectomy by means of a combination of microscopic surgery and an adjuvant endoscopic approach to remove the cholesteatoma matrix adherent to the vertebral body and the dura of the posterior fossa .
an 83-year - old caucasian male was referred to our department with otorrhea in his left ear which he had had for 3 months and a painful swelling behind the ear .
he also had a left facial palsy evaluated as v grade according to the house 
otomicroscopic evaluation revealed total perforation of the left hand tympanic membrane , through which the middle ear cavity appeared completely occupied by cholesteatomatous soft tissue .
temporal bone computed tomography revealed an extensive cholesteatoma that completely occupied the left middle ear cavity , the mastoid , and involved the petrous bones .
imaging showed erosion of the tegmen tympani , the bone around the geniculate ganglion , the semicircular canals , and the cochlea too . in the posterior section
, the lesion was found to extend and destroy part of the occipital bone and skull base .
it extended beyond the cranial theca and went distal to the body of the first cervical vertebra ( atlas ) which appeared eroded ( fig .
1 ) . 
 coronal ct ; extensive cholesteatoma eroding part of skull base bone and of the first cervical vertebra ( arrow ) .
a subsequent nuclear magnetic resonance imaging ( mri ) confirmed structural alteration of the petromastoid region and the presence of a 6    2    3 cm area of soft tissue which was hypointense on t1 and hyperintense on t2-weighted sequences , consistent with a diagnosis of cholesteatoma .
the mri confirmed the extension of the cholesteatoma cerebrum to the first cervical vertebra ( fig .
2 ) . 
 coronal mri , t1-weighted sequence ; presence of a hyperintense 6    2    3 cm soft tissue extended between the skull base and the first cervical vertebra .
intraoperative facial nerve using nim2 was planned.12 
  left infratemporal and infralabyrinthine subtotal petrosectomy was performed using a combined approach microscopic and endoscopic surgery .
first , the petrous bones and a massive cholesteatoma , which had occupied the lateral and posterior temporal areas on the left side and had caused widespread osteolisis of the mastoid cells , of the pyramid , and of the skull base theca , were removed through standard microscopic surgery ( figs . 3 and 4 ) .
furthermore , the remaining infralabyrinthine cholesteatoma matrix , which adhered to the body of the atlas was treated by means of delicate endoscopic dissection and bipolar coagulation ( fig .
rigid endoscopes at 0- and 30-degree angled with an outer diameter of 4  mm ( storz , germany ) were used .
images were recorded through a full high - definition ( hd ) camera ( stroz , germany ) , which was attached to the endoscope lens , and these images were displayed on a full hd monitor . in this manner ,
total removal of the lesion was achieved . no postoperative cerebrospinal fluid ( csf ) leaks or other complications occurred .
microscopic surgery ; residual cholesteatoma adherent to the transverse apophysis of the first cervical vertebra ( arrowhead ) .
microscopic view ( maximum magnification ) ; residual cholesteatoma adherent to the transverse apophysis of the first cervical vertebra ( arrowhead ) not entirely visible . 

adjuvant endoscopic surgery ; delicate dissection of the cholesteatoma matrix adhered to the transverse apophysis of the atlas clearly visible ( round knife ) .
pbc is an uncommon pathology but may cause severe functional damage and negatively affect the quality of life .
it has a known tendency to invade the labyrinth and fallopian canal , thereby causing facial nerve paralysis and permanent hearing loss .
it may also involve all the anatomical structures within the temporal bone and extend to the cerebellopontine angle or the infralabyrinthine region , which signifies a risk of damage to vital life structures ( internal carotid artery , jugular vein , sigmoid sinus , dura).1 
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  we have illustrated the case of a giant cholesteatoma which was classified as an infralabyrinthine  apical cholesteatoma according to sanna et al1 that eroded the labyrinth and the posterior fossa dura .
the case we have presented is a good example of a cholesteatoma which extends beyond the confines of the skull base and infralabyrinthine region .
indeed , although massive intracranial involvement of the bone , nerves , and vascular system of the posterior cranial fossa by such a huge cholesteatoma is not infrequent , this case is very unusual because the lesion went beyond the theca and reached the first cervical vertebra . to our knowledge , no previous cases of a cholesteatoma of this size have been documented .
traditionally , surgery performed on giant cholesteatoma of the petrous bone has contemplated lateral transtemporal or middle fossa microscopic surgery .
the choice of the best surgical approach is based on the location and extent of the lesion , hearing , preoperative facial nerve paralysis , and anatomic position of the internal carotid artery and jugular bulb .
it must guarantee that the cholesteatoma is visible in its entirety and ensure a sufficient exposure of the middle and posterior fossa dura , carotid artery , lateral sinus , jugular bulb , and facial nerve.2 
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  the main problems regarding pbc removal are residual matrix , recurrence / relapse , and postoperative complications . despite the illumination and magnification offered by the microscope
insufficient primary resection of the epidermal matrix , caused by a recess which was not detected by the microscope , may lead to recurrence of the disease in the patient / relapse.1 
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  in recent years , endoscopic surgical techniques , instrumentation , and knowledge have greatly improved due to an increased use of endoscopy in middle ear and mastoid surgeries.9 
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  marchioni et al16 recently proposed the endoscopic transcanal surgical approach for the treatment of iac and petrous bone lesions .
six of the 12 patients treated had a cholesteatoma of the tympanic cavity which affected the inner ear ( vestibule , geniculate ganglion , middle cranial fossa , and iac ) , although there was no massive infralabyrinthine extension .
kanzara et al4 reported the case of a petrous apex cholesteatoma which was removed in its entirety by means of an endoscopic approach .
they stated that an endoscopic permeatal approach circumvents some of the problems encountered in microscopic surgery .
it provides a better operative field and excellent vision of the important structures because , unlike the microscope , it bypasses the narrowest points and provides an excellent assessment of the surrounding structures .
moreover , they noted that the endoscopic approach provides more direct access to the apex . in our case , a left - sided infratemporal and infralabyrinthine subtotal petrosectomy was performed using a combined approach ( microscopic and endoscopic ) .
endoscopic petrous bone surgery offers some advantages as compared with the traditional microscopic technique , as it guarantees direct visual control of hidden areas such as the infralabyrinthine recess and its structures . in this way
, the eradication of the cholesteatoma in its entirety may be possible , reducing the risk of residual persistence and recurrence ( lower rate ) .
moreover , it may lower the risk of lesions of the dura and of the other functional and vital structures of the lateral skull base during cholesteatomatous matrix removal ( postoperative csf leaks).8 
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 14 as claimed by many authors , the main limitation of the endoscopic approach is that it is a one - hand surgical procedure that does not allow adequate drilling of the temporal bone to remove extensive lesions.9 
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  in conclusion , in future , endoscopic surgery will gain increasing importance in surgery of pbcs .
subsequently , a complementary endoscopic approach in hidden areas should be performed to remove the cholesteatomatous matrix and reduce possible postoperative complications and relapse .
 petrous bone cholesteatomas ( pbcs ) are epidermoid cysts , which have developed in the petrous portion of the temporal bone and may be congenital or acquired . 
 cholesteatomas arising in this region have a tendency to invade bone and functional structures and the middle and posterior fossae reaching an extensive size . 
 traditionally , surgery of a giant pbc contemplates lateral transtemporal or middle fossa microscopic surgery ; however , in recent years , endoscopic surgical techniques ( primary or complementary endoscopic approach ) are starting to receive a greater consensus for middle ear and mastoid surgeries . 
 we report the rare case of an 83-year - old caucasian male affected by a giant cholesteatoma that eroded the labyrinth and the posterior fossa dura and extended to the infralabyrinthine region , going beyond the theca and reaching the first cervical vertebra . 
 the giant cholesteatoma was managed through a combined approach ( microscopic and , subsequently , complementary endoscopic approach ) . in this case report 
 , we illustrate some advantages of this surgical choice . 
Introduction
Case Report
Discussion