Download Haynes, J

Sphenoidal Wing Meningioma Diagnosis Complicated by Existing Vision Loss
from Optic Disc Drusen
Abstract
44 year-old female with history of optic disc drusen presents with
monocular vision loss. Optometrically guided radiological workup reveals
compressive parasellar meningioma. Serial visual fields demonstrate tumor
induced functional decline and resolution post neurosurgical resection.
Case History
44 year-old Caucasian female presents with a chief complaint of insidious
loss of vision over the past 8 months. The patient’s ocular history is remarkable
for visual field loss OU secondary to bilateral optic disc drusen and reduced
central acuity OS. The patient’s medical history is positive for migraine
headaches and systemic allergies. She notes no recent headaches or
neurological changes. The patient has no other pertinent medical history. The
patient’s current medications include, loratidine 10 mg qday, methocarbamol 500
mg qhs prn, naproxen 250 mg bid, and promethazine 25 mg q6hours prn.
Pertinent Findings
BCVA were 20/20 OD and 20/150+ OS. A mild APD was noted
OS. EOMs were full. Amsler grid findings were normal OD, but the patient had
difficulty seeing the entire grid OS and reported that all lines appeared slanted
and wavy. Slit lamp exam findings were normal. Dilated eye examination
showed normal retinal structures with normal macular findings. Optic disc drusen
were noted OS>OD as previously described in prior exam findings, and were
consistent with prior photo documentation. OCT of macula was performed
showing normal findings OU. OCT of the retinal nerve fiber layer, although it
showed thinning of the RNFL based on normative databases OU, showed no
changes from prior readings. Humphrey visual field showed a stable superior
nasal defect OD, but the OS field showed substantial change from prior
readings. Scattered defects had previously been documented OS, but new
paracentral defects were now present, dropping the VFI from 71% to 51%. The
mean deviation had also decreased from -13.29 dB to -19.44 dB in the span of
less than one year.
MRI of the brain with and without contrast revealed a 3.2cm lesion
located at the midline, superior to the pituitary gland, and inferior to the optic
chiasm. The lesion’s anterior base was located on the planum sphenoidale and
it extended posteriorly to the posterior-most portion of the pituitary fossa.
Differential Diagnoses
·
Compressive space occupying lesion
·
Optic disc drusen
·
NAAION
Diagnosis and Discussion
The lesion was identified as a sphenoidal wing meningioma. The decision
to pursue further testing and identify the lesion could have been compromised by
the patient’s prior diagnosis of optic disc drusen. Had the visual changes been
misattributed to the drusen, the correct diagnosis could have substantially been
delayed. According to at least one study on suprasellar meningiomas, delay of
treatment was shown to be a prognostic factor for poorer visual outcomes. 1
This type of vision loss is not typical of drusen; especially with no change
in the appearance of the drusen from baseline photo documentation or changes
to the retinal nerve fiber layer with OCT imaging, as certain studies have shown
visual field defects correspond with progressively thinner nerve fiber layer on
OCT.2,3,4 Field defects most typical of optic nerve drusen include arcuate defects,
enlarged blind spot, and generalized constriction of the field. Effects on central
visual field and visual acuity are less common, and more often are associated
with secondary problems related to optic disc drusen such as ischemic optic
neuropathy5,6.
Meningiomas are about twice as likely to be found in women as in men,
and typically occur in patients aged 40-80. Most meningiomas are benign, and
can remain asymptomatic for long durations of time until they finally cause
symptoms from compression of nearby structures, as was the case with this
patient. Meningiomas located near the sphenoid bone can often compress the
optic nerve and lead to unilateral vision loss. They may also compress the
cavernous sinus and cause diplopia or numbness of the face, complaints which
this patient did not describe.7
Treatment/Management
The patient was scheduled shortly after diagnosis for surgery to remove
the tumor. After successful removal of the mass with orbitofrontal craniotomy
resection, the patient’s vision improved to 20/30. The visual field also showed
significant improvement in the paracentral defects that were previously
present. VFI increased to 81%, and mean deviation improved to -9.70 dB.
Conclusion
This case demonstrates the pivotal role that optometrists can play in a
patient’s healthcare. For this patient, a compressive lesion in the brain initially
presented with ocular complications before any other symptoms were
experienced. Had proper measures not been taken to identify the correct
underlying cause of the vision loss, treatment for the patient could have been
significantly delayed, and the visual outcome could have been adversely
affected.
Works Cited
1. Zevgaridis, D., R. J. Medele, A. Muller, A. C. Hischa, and H.-J. Steiger.
"Meningiomas of the Sellar Region Presenting with Visual Impairment: Impact of
Various Prognostic Factors on Surgical Outcome in 62 Patients." Acta
Neurochirurgica 143.5 (2001): 471-76.
2. Roh S, Noecker RJ, Schuman JS, Hedges TR, 3rd, Weiter JJ, Mattox C.
“Effect of optic nerve head drusen on nerve fiber layer thickness.”
Ophthalmology. 1998;105:878–85.
3. Gili, Pablo, Patricia Flores-Rodríguez, María Dolores Martin-Ríos, and Carmen
Carrasco Font. "Anatomical and Functional Impairment of the Nerve Fiber Layer
in Patients with Optic Nerve Head Drusen." Graefes Arch Clin Exp.10 (2013):
2421-428.
4. Casado, Alfonso, Gema Rebolleda, Laura Guerrero, Marina Leal, Inés
Contreras, Noelia Oblanca, and Francisco J. Muñoz-Negrete. "Measurement of
Retinal Nerve Fiber Layer and Macular Ganglion Cell–inner Plexiform Layer with
Spectral-domain Optical Coherence Tomography in Patients with Optic Nerve
Head Drusen." Graefes Arch Clin Exp Ophthalmol Graefe's Archive for Clinical
and Experimental Ophthalmology 252.10 (2014): 1653-660.
5. Lee, A., and M. Zimmerman. "The Rate of Visual Field Loss in Optic Nerve
Head Drusen." American Journal of Ophthalmology 139.6 (2005): 1062-066
6. Obuchowska, and Z. Mariak. "[Visual Field Defects in the Optic Disc Drusen]."
Klin Oczna 12th ser. 110.10 (2008): 357-60. Web
7. "Facts about Meningiomas." Brigham and Women's Hospital, 27 Feb. 2015.
Web. 13 Aug. 2015. <http://www.brighamandwomens.org/Departments
_and_Services/ neurosurgery/meningioma/meningiomafacts.aspx>