Visual Defects in Patients With Pituitary Adenomas: The Myth of Bitemporal Hemianopsia.
OBJECTIVE
The objective of this study was to test the hypothesis that bitemporal hemianopsia (BHA) is the most common visual field (VF) defect in patients with pituitary macroadenoma and to assess the degree of optic pathway compression necessary to produce visual defects.


METHODS
We reviewed the MRI findings and medical records of 119 patients with pituitary macroadenoma who had undergone formal assessment of VFs. We then evaluated the degree of optic pathway displacement caused by the pituitary macroadenoma, as observed on MR images. The classifications of optic pathway displacement included no contact, abutment but no displacement, mild displacement (< 3 mm), and moderate displacement (≥ 3 mm). Qualitative analysis classified VFs as normal or as having defects that were monocular, bitemporal, mixed (bitemporal with additional defects), homonymous, or nonspecific.


RESULTS
A total of 89 of 115 patients had an abnormal VF. Only one patient had true BHA. The most common defects were bitemporal or mixed defects (in 49 of 115 patients [42.6%]), likely because more than just the chiasm is often compressed by the pituitary macroadenoma. Classification of optic pathway displacement by the pituitary macroadenoma was as follows: 23 patients had no contact, eight had abutment but no displacement, 27 had mild displacement, and 57 had moderate displacement. In 78 of the 92 patients (84.8%) with pituitary macroadenoma that had contact with the optic pathway, contact was with the optic chiasm and the prechiasmal optic nerve. Of the 49 patients with bitemporal or mixed defects, 42 had moderate displacement of the optic pathway caused by their tumors.


CONCLUSIONS
BHA is exceedingly uncommon in patients with pituitary macroadenoma. However, although bitemporal and mixed defects are the most common abnormal VF findings, they were found in only 42.6% of patients. Such defects rarely occur if the tumor displaces the optic pathway less than 3 mm from baseline.
1 Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Medical Institutions, 600 N Wolfe St, Phipps B100F, Baltimore, MD 21287.|2 Department of Radiology, Chungnam National University Hospital, Daejeon, Korea.
In Ho
IH
Lee
3 Wilmer Eye Institute, The Johns Hopkins Medical Institutions, Baltimore, MD.
Neil R
NR
Miller
1 Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Medical Institutions, 600 N Wolfe St, Phipps B100F, Baltimore, MD 21287.
Elcin
E
Zan
1 Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Medical Institutions, 600 N Wolfe St, Phipps B100F, Baltimore, MD 21287.
Fabiana
F
Tavares
1 Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Medical Institutions, 600 N Wolfe St, Phipps B100F, Baltimore, MD 21287.
Ari M
AM
Blitz
4 Genometrics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD.
Heejong
H
Sung
1 Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Medical Institutions, 600 N Wolfe St, Phipps B100F, Baltimore, MD 21287.
David M
DM
Yousem
3 Wilmer Eye Institute, The Johns Hopkins Medical Institutions, Baltimore, MD.
Michael V
MV
Boland
D000236:Adenoma / Q000150:complications*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009897:Optic Chiasm / Q000473:pathology*; D010911:Pituitary Neoplasms / Q000150:complications*; D012189:Retrospective Studies; D014786:Vision Disorders / Q000175:diagnosis* / Q000209:etiology*
optic chiasm; pituitary adenoma; visual deficits