1、Olfactory Groove Meningioma,Introduction,Meningiomas are believed to arise from the meningothelial cap cells that are normally distributed through the arachnoid trabeculations The greatest concentration of meningothelial cells is found in the arachnoid villi at the dural sinuses, cranial nerve foram

2、ina, middle cranial fossa, and the cribriform plate,Olfactory groove meningiomas (OGM)are benign tumors that grow along the midline floor of the anterior cranial fossa.In rare instances, OGM can fall under Grade II and III of the WHOs classification OGM was successfully resected by Durante in 1885,

3、and this constitutes the first reported successful removal of a meningioma,Epidemiology,OGM account for 8 to 13% of all intracranial meningiomas The peak incidence is between ages 40 and 60 years, There is a 1:2 male/female ratio,Etiology,Cranial radiation is a definite risk factor for developing me

4、ningiomas. Patients with a history of cranial radiation therapy have a 4 times greater rate of meningioma formation compared with the general population. Head trauma Hormones (estrogen, progesterone, and androgen) Genetic mutations,Histological classification,Meningothelial Fibrous Angiomatous Psamm

5、omatous Transitional,Anatomy,OGM occur along the anterior fossa base overlying the area of the cribriform plate of the ethmoid bone, crista galli，frontosphenoid suture, and planum sphenoidale,OGM are usually midline, but as their size increases they may become asymmetric The frontal lobes are always

6、 displaced superiorly and posteriorly In larger tumors, inferior and lateral displacement of the optic nerves and chiasm is observed. Their growth can also occur inferiorly through the cribriform plate into the ethmoid sinus, through the planum sphenoidale into the sphenoid sinus, or laterally throu

7、gh the orbit,Blood supply,OGM can be highly vascularized tumors, Their main blood supply is derived from contributions of the external carotid artery OGM typically receive their blood supply from the anterior and posterior ethmoidal arteries, as well as branches of the middle meningeal artery and me

8、ningeal branches of the ophthalmic artery As they enlarge, variable contributions from the anterior cerebral arteries are observed,Tumor size and growth patterns,Roberto Pallini, MD, PhD Eduardo Fernandez: Olfactory Groove Meningioma. Report of 99 Cases Surgically Treated at the Catholic University

9、School of Medicine. World Neurosurgery 60:844-852, 2009,Symptoms,OGM are often asymptomatic because of their location. When they become large, they have a symptoms,Hyposmia or anosmia is one of the earliest presenting symptoms, but few patients seek medical care for this isolated symptom. At the tim

10、e of diagnosis, anosmia is noted in more than 50% of cases In a rare case, cacosmia has been reported secondary to an olfactory groove meningioma Later aspecific symptoms consist of headaches and personality changes,Loss of smell and taste Blurred vision Memory loss,Sleepiness Headaches Nausea,vomit

11、ing Personality changes Epilepsy Foster Kennedy syndrome,Rare cases are diagnosed invasion in the paranasal sinuses and consist of nasal obstruction, epistaxis, spontaneous cerebrospinal fluid (CSF) leaks, or meningitis,Clinical characteristics of patients with OGM,Supplementary examinations,CT MRI

12、The appearance of these tumors on MRI is similar to that of meningiomas found in other regions of the intracranial cavity or spinal canal. OGM classically appear as a homogeneously enhancing lesion with a dural attachment centered on the cribriform plate,CT,MRI,Differential Diagnosis,Key preoperativ

13、e imaging findings include the presence of bone scalloping as well as the absence of bone sclerosis and a dural tail Subfrontal schwannoma Tuberculum sellae meningiomas Olfactory neuro blastoma Metastatic tumors,Subfrontal Schwannoma,Subfrontal schwannoma,Tuberculum Sellae Meningiomas,Olfactory Neur

14、o Blastoma,Surgical Approaches,OGM usually require surgical treatment at time of diagnosis because of their size and associated mass effect Subfrontal approach Pterional approach Frontolateral approach Transsphenoidal,Selection Criteria,Tumor size Origin Placement according to midline The relationsh

15、ip of the anterior cerebral arteries Optic nerves,Transsphenoidal,Other therapies,Radiation therapy is generally reserved for recurrences that are refractory to surgical resection Chemo therapy Targeted molecular therapy,Complications,CSF leak Meningitis Epilepsy Brain ischemia Hydrocephalus Worseni

16、ng vision,Prognosis,OGM resection results were initially reported, mortality was from 17.3% to2.7% The recurrence rate of OGM ranges from 5 to 41%,Factors Afecting,Complete resection Brain retraction CSF leak Potential for vascular injury The size of the OGM,Foster Kennedy syndrome,Foster Kennedy sy

17、ndrome (FKS) is a rare neurological sign first described in 1911 by Robert Foster Kennedy FKS is defined as one-sided optic atrophy with papilledema in the other eye but with the absence of a mass,Presentation,Optic atrophy in the ipsilateral eye Papilledema in the contralateral eye Central scotoma (loss of vision in the middle of the visual fields) in the ipsilateral eye Anosmia (loss of smell) ipsilaterally,This syndrome is due to optic nerv