Figure 1
T2-weighted cranial MRI
Transverse images show an ovoid, hyperintense lesion (arrow) lateral to the optic nerve.
A case of orbital apex syndrome
SectionHead & neck imaging
Case TypeClinical Cases
AuthorsSchubert R, Radiologie am Europa-Center, Berlin, Germany
Connected authors
72 years, male
Clinical History
A 72-year-old man complained of a gradual loss of visual acuity in his right eye in conjunction with a right frontal headache involving the orbit. He had been suffering from recurrent sinusitis for decades, but never underwent endonasal surgery.
Imaging Findings
Cranial MRI showed a smoothly marginated, T2-hyperintense lesion in the right orbital apex, lateral to the optic nerve (Fig. 1). Complementary CT slices at the same level showed an ovoid lesion in the anterior clinoid process with soft-tissue attenuation and some rim sclerosis (Fig. 2). A small pneumatised ethmoid cell was seen medial to the optic canal. There were also circumscribed swellings of the mucous membranes in the sphenoid sinus and ethmoid cells, indicative of chronic sinusitis. The patient was referred to an ophthalmology department for further treatment.
Discussion
Orbital apex syndrome may be caused by inflammatory, infectious, neoplastic, traumatic, or vascular conditions. Optic neuropathy and ophtalmoplegia are the diagnostic hallmarks [1]. These findings may be accompanied by localised pain in the nasal quadrants of the orbit.
MRI and CT are the preferred modalities for evaluating the orbital apex. Often, both methods have to be used in combination, especially in lesions involving the bone [2]. Rhinogenic optic neuropathy secondary to sinus pathologies has been infrequently described in the literature [3]. Many of these cases have been attributed to mucoceles of the Onodi cells [4]. These pneumatised cells have been first described by the Hungarian rhinolaryngologist Adolf Onodi at the end of the nineteenth century. They are a variant of the utmost posterior part of the posterior ethmoid cells that extend supero-laterally to the sphenoid sinus, and may be located in close proximity to the optic canal [5]. Aeration of the anterior clinoid process is also often due to an Onodi cell [2]. Optic neuropathy caused by an Onodi cell mucocele or sinusitis is quite unusual [3]. However, the risk of a poor visual outcome is high. Therefore, therapeutic management should not be delayed, especially when signs of inflammation are present. Surgical treatment, either endonasal or transcranial, is often required to prevent permanent damage to the optic nerve [6].
MRI and CT are the preferred modalities for evaluating the orbital apex. Often, both methods have to be used in combination, especially in lesions involving the bone [2]. Rhinogenic optic neuropathy secondary to sinus pathologies has been infrequently described in the literature [3]. Many of these cases have been attributed to mucoceles of the Onodi cells [4]. These pneumatised cells have been first described by the Hungarian rhinolaryngologist Adolf Onodi at the end of the nineteenth century. They are a variant of the utmost posterior part of the posterior ethmoid cells that extend supero-laterally to the sphenoid sinus, and may be located in close proximity to the optic canal [5]. Aeration of the anterior clinoid process is also often due to an Onodi cell [2]. Optic neuropathy caused by an Onodi cell mucocele or sinusitis is quite unusual [3]. However, the risk of a poor visual outcome is high. Therefore, therapeutic management should not be delayed, especially when signs of inflammation are present. Surgical treatment, either endonasal or transcranial, is often required to prevent permanent damage to the optic nerve [6].
Differential Diagnosis List
Onodi cell mucocele
Sphenoid mucocele or sinusitis
Carotid artery aneurysm
Final Diagnosis
Onodi cell mucocele
References
[1] Yeh S, Foroozan R (2004) Orbital apex syndrome. Curr Opin Ophthalmol 15:490-8 (PMID: 15523194)
[2] Lim CC, Dillon WP, McDermott MW (1999) Mucocele involving the anterior clinoid process: MR and CT findings. AJNR 20:287-90 (PMID: 10094356)
[3] Fukuda H, Fukumitsu R, Andoh M, Suzuki T, Yamana N, Kataoka H, Iwasaki K (2010) Small Onodi cell mucocele causing chronic optic neuropathy: case report. Neurol Med Chir (Tokyo) 50:953-5 (PMID: 21030816)
[4] Yoshida K, Wataya T, Yamagata S (2005) Mucocele in an Onodi cell responsible for acute optic neuropathy. Br J Neurosurg 19:55-6 (PMID: 16147585)
[5] Kantarci M, Karasen RM, Alper F, Onbas O, Okur A, Karaman A (2004) Remarkable anatomic variations in paranasal sinus region and their clinical importance. Eur J Radiol 50:296-302 (PMID: 15145491)
[6] Loo JL, Looi AL, Seah LL. (2009) Visual outcomes in patients with paranasal mucoceles. Ophthal Plast Reconstr Surg 25:126-9 (PMID: 19300156)
Case information
| URL: | https://www.eurorad.org/case/9294 |
| DOI: | 10.1594/EURORAD/CASE.9294 |
| ISSN: | 1563-4086 |
Figure 2
Transverse MSCT
Soft-tissue attenuation cavity in the right anterior clinoid process (bright arrow), lateral to the optic canal. Medially to the canal, there is an aerated ethmoid cell (dark arrow).
T2-weighted cranial MRI
Transverse images show an ovoid, hyperintense lesion (arrow) lateral to the optic nerve.
Transverse MSCT
Soft-tissue attenuation cavity in the right anterior clinoid process (bright arrow), lateral to the optic canal. Medially to the canal, there is an aerated ethmoid cell (dark arrow).