Encompassing approximately 12% of all meningiomas in the base of the skull, an olfactory groove meningioma (OGM) arises from the arachnoidal cells located in the lamina cribrosa of the ethmoid bone and frontosphenoidal suture [1] [2] [3]. One of the most important features of OGM is its frequent delay in the diagnosis due to lack of clinical suspicion despite the presence of typical symptoms and up to 3 years may pass before the condition is recognized [3] [4] [5]. Anosmia and headaches are considered to be the primary signs [1] [2] [6], but they are often misdiagnosed as sinusitis, migraines or neuralgia [6]. Moreover, visual deficits (hypophthalmos, visual acuity impairment, and vision loss), nasal obstruction, hyposmia, epistaxis, and papilledema may be seen [3]. In up to a third of cases, psychiatric complaints in the form of disinhibition, psychosis, personality changes, confusion, or even cognitive decline (eg. memory loss) are noticed [1] [3] [5] [7]. In advanced stages of tumor development, the appearance of seizures is common, whereas hemiparesis is also observed in a number of sufferers [3]. For still unknown reasons, the majority of case studies in the literature have identified a significant predominance towards female gender [1] [3] [7].

• Wound Infection

  A wound infection also 5%, A subdural hygroma requiring a subdural-peritoneal shunt in 5%. Disturbance in mental function and personality changes when present preoperatively or transiently in the postoperative period usually recover completely. [meningiomas.org]

  Wound infection occurred in one patient (5%) and postoperative hematoma occurred in three patients (15%) [Table 4]. [mmj.eg.net]

• Lymphadenopathy

  There was no significant lymphadenopathy. There was no dependent oedema. Naso-pharyngeal examination did not reveal any abnormality. Respiratory system and cardiovascular system did not reveal any abnormality. The liver and spleen were not palpable. [ijo.in]

• Anosmia

  The patient had right-sided anosmia. Computed tomography and magnetic resonance imaging showed a lesion in the frontal lobe that was deviated to the right and attached to the olfactory groove. [ncbi.nlm.nih.gov]

  When following up one of these patients for a period of 24 months anosmia ipsilateral to the tumour was still present. The four patients with bilateral anosmia had a large bilateral tumour, whereas all others had a lateralised tumour (table). [jnnp.bmj.com]

  His anosmia persisted and he had diplopia on looking down after the operation. The diplopia resolved after 6 months but the anosmia remained. He has since resumed work. Figure 1. [cfp.ca]

  As a result, the olfactory tracts are displaced laterally and are compressed, leading to anosmia. The base of the frontal lobe is displaced superiorly and posteriorly. [mdmag.com]

  When symptomatic, they can produce Foster Kennedy syndrome (anosmia, ipsilateral optic atrophy, contralateral papilledema), metal status change, urinary incontinence Histological variables follow WHO grading I to III (from low recurrence to high rates [radiologyinthai.blogspot.com]

• Hyposmia

  Anosmia and hyposmia was present in 9 and 10 cases respectively. Visual disturbances was seen in 16 cases. Radiological bone changes in form of hyperostosis and bone erosion was seen in 14 cases. [journalijar.com]

  Subfrontal schwannoma without hyposmia – case report Neurol Med Chir (Tokyo) 2004 ; 44 : 591-594 [cross-ref] [38] Sato S., Toya S., Nakamura T., Ohtani M., Imanishi T., Kodaki K., and al. [em-consulte.com]

  Six patients had anosmia ipsilaterally to the tumour, four of them were completely anosmic, two had contralateral hyposmia or normosmia. [jnnp.bmj.com]

  Moreover, visual deficits (hypophthalmos, visual acuity impairment, and vision loss), nasal obstruction, hyposmia, epistaxis, and papilledema may be seen. [symptoma.com]

  The time frame noted from the development of initial symptoms to the time of diagnosis varies substantially between different series and has been reported to be up to 14 years. 9 Hyposmia or anosmia is one of the earliest presenting symptoms, but few [clinicalgate.com]

• Nasal Discharge

  Patient denied of any nasal discharge, epistaxis, visual impairment and any neurologic abnormalities. Family history was unremarkable. [file.scirp.org]

• Pharyngitis

  Naso-pharyngeal examination did not reveal any abnormality. Respiratory system and cardiovascular system did not reveal any abnormality. The liver and spleen were not palpable. [ijo.in]

• Psychiatric Symptoms

  In larger tumors, encroachment of the optic nerves can lead to papilledema and loss of visual acuity. 1 Correct diagnosis is often delayed because of longstanding psychiatric symptoms that lead to misdiagnosis and mistreatment. [mdmag.com]

  The anatomic location of the olfactory groove meningioma may cause prolonged psychiatric symptoms before the onset of more overt neurologic deficits. [operativeneurosurgery.com]

  The anatomic location of OGMs may cause prolonged psychiatric symptoms before the onset of more overt neurologic deficits. For these reasons, OGM are among the largest intracranial tumors we see [3]. [mmj.eg.net]

• Flat Affect

  Occasionally, an early stage of aggressiveness has been reported. 11, 12 Exceptional cases of euphoria have also been described. 13 Patients then develop a flat affect as well as some short-term memory problems from subtle frontal lobe dysfunction. [clinicalgate.com]

  Physical and neurologic evaluations were remarkable for a flat affect, psychomotor retardation, and urinary incontinence. She was diagnosed with a major depressive episode, and inpatient medical treatment was started. [mdmag.com]

• Olfactory Hallucination

  hallucination [医]嗅幻觉,幻嗅 olfactory islands [医]嗅岛 olfactory knob 嗅小结 olfactory lobe 嗅叶 olfactory membrane [医]嗅膜 olfactory mucosa 嗅粘膜 olfactory mucosa membrane 嗅粘膜 olfactory muscous membrane 嗅粘膜 olfactory nerve 嗅神经 olfactory nerve filament [医]嗅神经丝 olfactory [fastdict.net]

• Headache

  A 55-year-old woman presented with a longstanding history of headache and personality change. Preoperative imaging suggested an olfactory groove meningioma invading the posterior nasal space. [ncbi.nlm.nih.gov]

  Souza et al., 2003 [15] 27, M OGS Headache Yes Cystic Homogeneous n.r. [docslide.com.br]

  Case Discussion A 69-year-old male presenting with headache for one week and diplopia. 2 public playlists includes this case Related Radiopaedia articles Meningioma Promoted articles (advertising) Case information rID: 8334 Published: 24th Jan 2010 Last [radiopaedia.org]

  EEA Clinical Case Study The Patient A 35-year-old woman was experiencing headache and vision loss from pressure and swelling in her brain related to a large tumor at the base of her skull. The tumor was an olfactory groove meningioma. [upmc.com]

• Foster-Kennedy Syndrome

  Foster-kennedy syndrome in a case of olfactory-groove meningioma. Indian J Ophthalmol 1965;13:75-8 How to cite this URL: Markand O N, Chandrakar K L. Foster-kennedy syndrome in a case of olfactory-groove meningioma. [ijo.in]

  We believe that this patient with olfactory groove meningioma represents a rare case of Foster Kennedy syndrome and optociliary shunt vessels. [ncbi.nlm.nih.gov]

  Just saying....since that's what I have to do Gadi Medical Student Foster-Kennedy's syndrome due to olfactory groove #Meningioma. pope Medical Student Remember, Foster-Kennedy Syndrome has a very specific set of findings. [app.figure1.com]

  When symptomatic, they can produce Foster Kennedy syndrome (anosmia, ipsilateral optic atrophy, contralateral papilledema), metal status change, urinary incontinence Histological variables follow WHO grading I to III (from low recurrence to high rates [radiologyinthai.blogspot.com]

  The triad of anosmia and unilateral optic atrophy with contralateral papilledema first described in the Foster Kennedy syndrome is rare and can be observed in other conditions. 16 – 19 In addition to the Foster Kennedy syndrome, optociliary shunting may [clinicalgate.com]

Given the slowly progressive and underrecognized nature of OGM, it is essential to perform a comprehensive and meticulous workup. Firstly, a detailed patient history that will assess the course and progression of symptoms should be obtained, followed by a thorough physical examination, with a particular emphasis on the neurological examination. However, olfactory testing frequently yields normal findings, thus the typical clinical picture might be absent [2]. To determine the underlying etiology (but also to plan the optimal therapeutic strategy), imaging studies need to be employed. Computed tomography (CT), although sometimes sufficient to make the diagnosis [5], has shown to be of limited use in the assessment of olfactory groove meningioma (particularly in the postoperative setting when patients are checked for tumor recurrence) [4]. For this reason, MRI (sometimes with gadolinium contrast enhancement) is the recommended study, showing an isointense or slightly hypointense signaling on T1-weighted studies and a hyperintense signal on T2-weighted studies compared to the cerebral cortex in the case of OGM [3] [8]. Because meningiomas have a wide differential diagnosis, additional exams, such as diffusion-weighted imaging, diffusion tensor imaging (DT), and MR spectroscopy are frequently used to further solidify the diagnosis [8].

1. Nakamura M, Struck M, Roser F, Vorkapic P, Samii M. Olfactory groove meningiomas: clinical outcome and recurrence rates after tumor removal through the frontolateral and bifrontal approach. Neurosurgery. 2007 May;60(5):844-852.
2. Welge-Luessen A, Temmel A, Quint C, Moll B, Wolf S, Hummel T. Olfactory function in patients with olfactory groove meningioma. J Neurol Neurosurg Psychiatry. 2001;70(2):218-221.
3. Pallini R, Fernandez E, Lauretti L, et al. Olfactory groove meningioma: report of 99 cases surgically treated at the Catholic University School of Medicine, Rome. World Neurosurg. 2015;83(2):219-231.e1-3.
4. Snyder WE, Shah MV, Weisberger EC, Campbell RL. Presentation and Patterns of Late Recurrence of Olfactory Groove Meningiomas. Skull base surgery. 2000;10(3):131-139.
5. Leo RJ, DuBois RL. A case of olfactory groove meningioma misdiagnosed as schizophrenia. J Clin Psychiatry. 2016;77(1):67-68.
6. Tsikoudas A, Martin-Hirsch DP. Olfactory groove meningiomas. Clin Otolaryngol Allied Sci. 1999;24(6):507-509.
7. Pepper JP, Hecht SL, Gebarski SS, Lin EM, Sullivan SE, Marentette LJ. Olfactory groove meningioma: discussion of clinical presentation and surgical outcomes following excision via the subcranial approach. Laryngoscope. 2011;121(11):2282-2289.
8. Tamrazi B, Shiroishi MS, Liu C-SJ. Advanced Imaging of Intracranial Meningiomas. Neurosurg Clin N Am. 2016;27(2):137-143.