co - incidental aneurysms are detected almost seven times more frequently in patients with pituitary adenomas ( pa ) than in patients with other brain tumors2,12,19 ) . however , the vast majority of these aneurysms are located outside the sellar - region . aneurysms of the cavernous or supraclinoid carotid that encroach into the pa as in the present case are very rare . the prevalence of sellar - region 's aneurysm among others is 1 - 2%14 ) . some possible treatment options include simultaneous microsurgical managements ( frontopterional or supraorbital approach ) , transsphenoidal microsurgery after clipping or coil embolization , and two stage procedures combined with radiotherapy or radiosurgery ( residual mass)2,13,14,19 ) . we report a patient with an incidental superior hypophygeal artery aneurysm embedded within a non - functional pa which was treated by transsphenoidal surgery after endovascular coil embolization . the results of the neuro - ophalmologiclal examination revealed bitemporal hemianopsia . magnetic resonance ( mr ) however , the axial or coronal mr images presented a flow void in the medial portion of the right internal carotid artery ( ica ) ( fig . these mr images raised the suspicion of a coexisting intrasellar aneurysm before the planned transsphenoidal procedure . consequently , 3-dementional computed tomography ( ct ) angiogram demonstrated the opthalmic segment of the right distal ica ( fig . four vessels angiogram confirmed a right superior hypophygeal artery aneurysm and the saccular aneurysmal sac that had a 4.13 mm neck , 6.27 mm width , and 3.99 mm height ( fig . first , we treated the aneurysm by coil embolization with the goal of maintaining the patency of the ica ( fig . two months later , she underwent surgery via the transsphenoidal microsurgical approach for the removal of the tumor . we carefully dissected the tumoral portion surrounding the coil - treated aneurysm and a total resection of the tumor was successfully achieved . mr at 8 month follow - up after surgery demonstrated complete obliteration of the aneurysm and no sign of regrowth of the adenoma ( fig . the incidence of intracranial aneurysm among patients with pa is 0.5% , based on the results obtained from 5762 autopsies6 ) . since then , many studies have reported a 0.5 - 7.4% incidence of intracranial aneurysm among patients with pa , with a general consensus that this association is higher than the prevalence of intracranial aneurysm among the general patient population7,11,17 ) . in addition , this association is generally thought to be higher in patients with pa compared with other brain tumors , although the manner in which a pa contributes to the formation of an intracranial aneurysm remains unclear5,17 ) . al.9 ) have reported that coexistence of intracranial aneurysm was detected in 18 of 800 patients with pa ( 2.3% ) . and then , the intracranial aneurysm in patients with pa were located in the internal carotid artery in 9 patients ( 50% ) , the middle cerebral artery in 6 patients ( 33.3% ) , the anterior cerebral artery in 2 patients ( 11.1% ) , and the vertebrobasilar artery in 1 patient ( 5.6% ) . hanak et al.4 ) have conducted a pubmed ( national library of medicine ) literature review to identify all studies reporting non - iatrogenic aneurysms with intrasellar extension , as confirmed by ct or mr imaging and angiography . intrasellar aneurysms were reported in functional pa such as growth - hormone pa and prolactinoma9,12,14,18 ) . but , the coexistence of a superior hypophygeal aneurysm and a non - functional pituitary adenoma was reported in one case so far19 ) . direct infiltration by the tumor , and increased tension or blood flow in vessels supplying the tumor have been suggested as mechanisms for this coexistence of intracranial aneurysm and pa12 ) . approximately 50% of these patients have acromegaly , suggesting that high gh and igf-1 levels or their biological effects may be implicated in the genesis of aneurysms . a high level of igf-1 induces artery dilation , atherosclerotic and degenerative changes of the artery walls of the circle of willis , tumor invasion and tumor - directed neovessels1,9 ) . these intrasellar aneurysms mimicking pituitary tumors are usually asymptomatic , although they can sometimes present with hypopituitarism ( fewer than 40 cases in the literature ) . nevertheless , different clinical presentations may occur such as pituitary apoplexy or fatal epistaxis as a result of aneurysmal bleeding into the adenoma . teng et al.15 ) demonstrated that the finding of flow voids is 100% specific for aneurysms . however , the sensitivity of the presence of flow voids on noncontrast t1-weighted imaging , postcontrast t1-weighted imaging , and t2-weighted imaging was 88% , 22% , and 88% , respectively . furthermore , olsen et al.10 ) observed that only 12 of 15 giant aneurysms ( 80% ) showed signs of intraluminal blood flow . these results indicate that misdiagnosis of such coexistence can be possible . in our case , the axial or coronal mr images presented a flow void in the medial portion of the right ica . thus , 3-dimentional ct angiogram and 4 vessels angiogram were performed and confirmed a right superior hypophyseal artery aneurysm . incidental intracranial aneurysms located distant from the lesion are considered to have little relevance to surgical management of most patients . however , aneurysms of the major arteries adjacent to pituitary and suprasellar tumors are additional hazards to surgical treatment . previous knowledge of the presence and anatomy of such aneurysms is important during separation of the tumor capsule from major vessels , or removal of an intracavernous extension of a tumor lying close to the carotid artery3,7 ) . treatment of each lesion becomes more challenging when the aneurysm lies inside the sella turcica . endovascular coil placement is an effective treatment option if it is performed before resection of the adenoma , particularly in locations such as the cavernous carotid artery or the paraclinoid segment . transsphenoidal microsurgical removal of the adenoma can still be performed safely in a subsequent surgical setting , but avoidance of direct contact with the aneurysm is suggested14,19 ) . the size and shape of if the tumor is smaller than a type a suprasellar ( hardy classification ) , endovascular coil embolization followed by transsphenoidal microsurgical removal of the pa may be feasible and beneficial18 ) . if it is not possible to achieve a total resection of pa without manipulating the aneurysm via the transsphenoidal route , simultaneous microsurgical management may be a better treatment option2 ) . in addition , adjuvant radiotherapy or radiosurgery will be considered if recurrent tumor is found during follow up8 ) . in our case , we treated firstly the aneurysm by coil embolization and pa by the transsphenoidal microsurgical approach two months later . we report a patient with an incidental superior hypophygeal artery aneurysm embedded within a non - functional pa . therefore , careful evaluation of pre - operative imaging is necessary , especially in those with atypical symptoms such as our patient . prior treatment of the aneurysm is advisable to avoid catastrophic bleeds during transsphenoidal microsurgical removal of the adenoma .