CASE REPORTS

Reversible Posterior
Leukoencephalopathy Occurring during
Resection of a Posterior Fossa Tumor:
Case Report and Review of the Literature
John L. Moriarity, Jr., M.D., Michael Lim, M.D.,
Phillip B. Storm, M.D, Norman J. Beauchamp, Jr., M.D.,
Alessandro Olivi, M.D.
Departments of Neurological Surgery (JLM, ML, PBS, AO) and Radiology (NJB), The Johns
Hopkins Hospital, Baltimore, Maryland

OBJECTIVE AND IMPORTANCE: Our goal was to present a clinically and
radiographically documented case of reversible posterior leukoencephalopathy (RPL) that occurred during resection of a posterior fossa tumor.
Although RPL has been previously described in multiple nonsurgical
settings, we hope that this case description makes RPL more clinically and
radiographically recognizable to neurosurgeons.
CLINICAL PRESENTATION: RPL is the clinical syndrome of headaches,
altered mental status, seizures, and visual loss, with radiographic findings
of reversible parieto-occipital changes on cerebral computed tomographic and magnetic resonance imaging scans. It has been previously
reported in the settings of malignant hypertension, renal disease, eclampsia, and immunosuppression. To our knowledge, the patient presented
represents the first clinically and radiographically documented case of
RPL occurring during resection of a posterior fossa tumor. The patient
intraoperatively exhibited wide fluctuations in blood pressure and awoke
with clinical and radiographic findings consistent with RPL.
INTERVENTION: Aggressive intraoperative and postoperative management
of the patient’s blood pressure, supportive intensive care, rehabilitation,
and close radiographic follow-up were performed.
CONCLUSION: RPL can occur as a result of intraoperative variations in
blood pressure, even among young, previously healthy individuals. With
the aforementioned interventions, the patient experienced significant
clinical and radiographic recovery. (Neurosurgery 49:1237–1240, 2001)
Key words: Ependymoma, Hypertensive encephalopathy, Occipitoparietal encephalopathy, Posterior fossa surgery, Reversible posterior leukoencephalopathy

I

n the late 1920s, the term malignant
hypertension was first applied to patients with hypertension causing papilledema and retinal hemorrhage (6). Also
at that time, Oppenheimer (8) introduced the term hypertensive encephalopathy to describe the syndrome of head-

aches, altered mental status, and
seizures. In 1996, Hinchey et al. (5) defined reversible posterior leukoencephalopathy (RPL) as a combination of
headaches, altered mental status, seizures, and visual loss, with the radiographic findings of predominantly

white-matter changes in the parietooccipital region. Only 1 of the 15 patients described by Hinchey et al. (5)
was younger than 18 years of age. However, RPL was subsequently also observed among pediatric patients (9).
The syndrome of RPL has been observed in multiple clinical settings. Although the majority of these settings involve significant elevations in blood
pressure (malignant hypertension, hypertensive encephalopathy, eclampsia, or
acute glomerulonephritis), multiple cases
have been observed in the absence of hypertension (immunosuppression, interferon therapy, or renal insufficiency).
Radiographically, patients bilaterally
exhibit low attenuation on computed tomographic scans and high signal intensity
on T2-weighted magnetic resonance imaging (MRI) scans, in the parieto-occipital
region (10). The findings are frequently
confined to the region of the posterior
circulation but often with sparing of the
midline portion of the occipital lobes. As
the name implies, white-matter findings
predominate. However, even in the original description by Hinchey et al. (5), 4 of
the 15 patients exhibited radiographic
changes involving the gray matter as well
(5). The high frequency of accompanying
gray-matter changes (1, 9, 15) has
prompted some to question the validity of
the term leukoencephalopathy (9, 11).
The outcomes of RPL are generally favorable. The majority of clinical and radiographic changes resolve in 2 to 4
weeks, especially with prompt control of
blood pressure or cessation of the associated immunosuppressant or chemotherapeutic treatment (5, 9). As with the
case presented here, however, there
are multiple cases in which some neurological or radiographic sequelae persist as a result of frank infarction (1, 9,
11). To our knowledge, the case we
present here is the first clinically and
radiographically documented case of
RPL occurring intraoperatively.

CASE REPORT
A 19-year-old male patient with an
unremarkable medical history presented to his primary physician with

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complaints of headaches and vomiting
for 6 weeks. He was referred to a local
neurosurgeon for evaluation of bilateral
papilledema and blurring of vision.
Computed tomographic scans revealed
hydrocephalus and a fourth-ventricular
tumor. The patient underwent ventriculoperitoneal shunt placement (the cerebrospinal fluid cytological analysis
yielded negative results). MRI scans obtained after shunting revealed resolution of the hydrocephalus and a heterogeneously enhancing fourth-ventricular
tumor (Fig. 1). During the examination,
the patient was alert and conversant,
with only mild dysmetria and gait
ataxia. He was then referred to our institution for tumor resection.
The patient was positioned prone,
with rigid cranial fixation, and a routine
midline suboccipital exposure was performed. Retraction of the tonsils revealed a large ependymoma occupying
the fourth ventricle. Microsurgical resection was performed in the standard
manner.
Two hours after the beginning of the
procedure, the patient’s cerebellum became significantly swollen. The patient
then experienced alternating hypo- and

FIGURE 1. MRI scans obtained after
shunting. A T2-weighted scan obtained
after placement of a right parietooccipital shunt revealed resolution of
the hydrocephalus (A, axial view).
T1-weighted scans obtained without (B,
sagittal view) and with (C, sagittal, and
D, axial views) gadolinium administration demonstrated an enhancing mass
filling most of the fourth ventricle.

hypertensive episodes, with pressures
ranging from 85/50 to 200/130 mm Hg,
for approximately 45 minutes. Dissection was intermittently suspended during this period, while the anesthesiologist managed the patient’s blood
pressure with Neo-Synephrine (Bayer
Corp., Morris Township, NJ), esmolol,
and labetalol. In addition, the flexion of
the patient’s neck was reduced, his head
was elevated, mannitol was administered, and the patient underwent hyperventilation. After the cerebellar swelling
resolved and the blood pressure normalized, a gross total resection was performed without further incident.
While emerging from anesthesia, the
patient experienced two generalized
tonic-clonic seizures. Emergency computed tomographic scans revealed an
open fourth ventricle, no residual tumor
bulk, no hematoma, and no hydrocephalus. However, there was bilateral low
attenuation in the parieto-occipital regions (Fig. 2). The patient was treated
with phenytoin. An electroencephalogram obtained at that time was negative
for epileptiform activity. MRI scans performed 4 days later revealed bilateral
T2-weighted signal hyperintensity involving the parietal and occipital lobes.
Both gray- and white-matter signal
changes were noted (Fig. 3).
Postoperatively, the patient was lethargic for 5 to 7 days, with intermittent
headaches and patchy visual loss. His
seizures were pharmacologically controlled, and he remained normotensive.
Ten days after surgery, the patient was
transferred to an inpatient rehabilitation
facility, where he exhibited steady
improvement.
Eight weeks after tumor resection, MRI
revealed significant resolution of the

parieto-occipital changes (Fig. 4). However, regions of cortical laminar necrosis,
suggesting infarction, were also noted
(Fig. 5). On examination, the patient was
conversant, ambulatory, and headachefree. He continued to exhibit a mildly disconjugate gaze, but an ophthalmological
examination revealed full visual fields.
The patient has remained seizure-free
while receiving anticonvulsants.

DISCUSSION
To our knowledge, this case represents the first clinical and radiographic
description of RPL occurring during resection of a posterior fossa tumor. Postoperatively, our patient manifested all
of the clinical characteristics of RPL, including headaches, visual loss, seizures,
and mental status changes. In addition,
scans obtained in the immediate postoperative period demonstrated bilateral
parieto-occipital areas of low radiodensity (Fig. 2) and T2-weighted signal hyperintensity (Fig. 3). The mixed involvement of gray and white matter, the
anatomic distribution of the changes,
and the bilateral symmetry were identical in appearance to other cases of RPL
(1, 5, 9, 10). Furthermore, the sparing of
the midline occipital region and the lateral extension of the changes (beyond
the watershed region) suggest that simple posterior circulation infarction is
less likely. Follow-up T2-weighted
scans demonstrated significant resolution of the parieto-occipital changes
(Fig. 4). However, there were persistent
areas of focal encephalomalacia and T2weighted signal hyperintensity. Corresponding T1-weighted scans demonstrated linear signal hyperintensity
consistent with cortical laminar necrosis

FIGURE 2.
Immediately postoperative, axial
computed tomographic scans without enhancement.
The fourth ventricle
appeared to be
devoid of tumor or
blood clot (A), and
there was no evidence of hydrocephalus (B and C). Regions of low radiodensity
were present in both parieto-occipital regions (B and C) and appeared to involve
both white and gray matter.
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REFERENCES

FIGURE 3. Axial, T2-weighted, MRI
scans obtained 4 days after tumor
resection, revealing bilateral parietooccipital areas of high signal intensity
involving both gray (arrowheads) and
white matter. There was no significant
mass effect, and the superior sagittal
sinus remained patent; a normal flow
void was demonstrated (arrow).

FIGURE 5. Axial, T1-weighed, noncontrast-enhanced, MRI scans obtained
8 weeks after tumor resection, demonstrating linear areas of T1-weighted signal hyperintensity that corresponded to
the cerebral cortex and primarily
involved the left occipital and parietal
regions (arrows). There was no significant mass effect.
the posterior vascular distribution,
which has less sympathetic innervation (3, 4, 7, 12, 13). A second proposed
mechanism involves reflex cerebral
vasoconstriction in response to supranormal systemic pressure. This
has been demonstrated angiographically and would explain cases in
which there is involvement of gray
matter and occasional progression to
infarction (2, 12, 14). In contrast, nonhypertensive cases (related to immunosuppressant or chemotherapeutic
treatment, for example) are possibly
caused by alterations in the bloodbrain barrier or cytotoxic effects on the
cerebrovascular endothelium (5).

FIGURE 4. Axial, T2-weighted, MRI
scans obtained 8 weeks after tumor
resection. Bilateral areas of
T2-weighted signal hyperintensity
involving the parietal and occipital
lobes could again be observed. In comparison with the previous examination
results (Fig. 3), there was significant
resolution. The areas of greatest signal
resolution were in the white matter.
(Fig. 5). This constellation of findings
was thought to represent partial resolution of the patient’s posterior leukoencephalopathy, with some focal areas of
infarction.
The pathophysiological features of
RPL remain unknown. For cases in
which hypertension is thought to be
the inciting event, two main theories
predominate. The first suggests that
breakthrough vasodilation occurs as
the blood pressure exceeds the autoregulatory capability of the cerebral
vasculature. This is consistent with the
tendency for the edema pattern to be
primarily vasogenic (largely sparing
gray matter), reversible, and involving

CONCLUSION
We describe a case of RPL that occurred during routine resection of a posterior fossa tumor. Although RPL has
been previously described in multiple
nonsurgical settings, we hope that this
case description makes RPL more clinically and radiographically recognizable
to neurosurgeons.
Received, March 16, 2001.
Accepted, June 29, 2001.
Reprint requests: Alessandro Olivi, M.D.,
Department of Neurological Surgery, The
Johns Hopkins Hospital, 600 North Wolfe
Street, Meyer 7-113, Baltimore, MD 21287.
Email: aolivi@jhmi.edu

1. Ay H, Buonanno FS, Schaefer PW, Le DA,
Wang B, Gonzalez RG, Koroshetz WJ: Posterior
leukoencephalopathy without severe hypertension: Utility of diffusion-weighted MRI. Neurology 51:1369–1376, 1998.
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L, Wang A, Pessin MS, Lamy C, Mas J, Caplan
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syndrome. N Engl J Med 334:494–500, 1996.
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D: Occipital-parietal encephalopathy: A new
name for an old syndrome. Pediatr Neurol 16:
145–148, 1997.
10. Port JD, Beauchamp NJ Jr: Reversible intracerebral pathologic entities mediated by vascular
autoregulatory dysfunction. Radiographics 18:
353–367, 1998.
11. Schwartz RB: A reversible posterior leukoencephalopathy syndrome. N Engl J Med 334:
1743–1746, 1996 (comment).
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Mantello MT, Garada B, Holman BL: Hypertensive encephalopathy: Findings on CT, MR imaging, and SPECT imaging in 14 cases. AJR
Am J Roentgenol 159:379–383, 1992.
13. Strandgaard S, Paulson OB: Cerebral autoregulation. Stroke 15:413–416, 1984.
14. Trommer BL, Homer D, Mikhael MA: Cerebral
vasospasm and eclampsia. Stroke 19:326–329,
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COMMENTS
The authors report a case of a patient
with reversible posterior leukoencephalopathy (RPL) that occurred during the
resection of a posterior fossa tumor. As
they point out, this fairly well-described
syndrome includes presenting symptoms of headache, mental status
changes, visual disturbances, and sei-

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Moriarity et al.

zures in conjunction with characteristic,
often completely reversible, radiographic white matter changes in the occipital lobes. Although Moriarity et al.
report the first association of RPL with
the resection of a posterior fossa tumor,
the occurrence of RPL in this instance
probably was related not specifically to
the type of surgery but rather to the
hemodynamic instability that occurred
during surgery. Nonetheless, neurosurgeons ought to be aware of this neurological entity, and its occurrence in this
case as a complication of an intracranial
procedure is worth noting.
John R. Adler, Jr.
Stanford, California
Moriarity et al. present an interesting
case of a 19-year-old man with 6 weeks
of headache and vomiting who was
eventually found to harbor a fourth ventricular ependymoma. During surgery,
the patient experienced extreme fluctuations in blood pressure and experienced postoperative seizures, altered
mental status, and radiographic abnormalities involving predominately the
white matter of the posterior parietooccipital regions. The authors think that
this case represents RPL and present it
because it occurred in the setting of a
posterior fossa tumor resection. They
think that this entity, which has been
described in conjunction with a number
of medical conditions, may be unfamiliar to neurosurgeons. Although the ac-

ronym RPL probably is relatively uncommon in the neurosurgical literature,
I think that its underlying concept is
well understood by most neurosurgeons. Certainly, the concept of a hyperperfusion syndrome with “leaky” capillaries that produce extensive white
matter edema is well known to neurosurgeons, and the tendency for this
white matter edema often to be most
prominent in the posterior parietooccipital regions I myself know well.
The prototypical condition in which this
presentation occurs is hypertensive encephalopathy, although occasionally
even neurosurgeons encounter other examples. Although the vasogenic edema
within the white matter is certainly reversible, the underlying condition or
conditions that led to the edema often
can result in more permanent damage.
In the case described here, one wonders
whether the episodes of hypotension resulted in infarction within areas of the
brain that were edematous and had contained perfusion. Regardless of what
this entity is called, the key is to remember that it is potentially reversible with
meticulous management of blood pressure and meticulous control of intracranial pressure if intracranial pressure,
too, is elevated.
Robert E. Breeze
Denver, Colorado
The authors call attention to a rare
but important entity, RPL. It is surpris-

ing that an occurrence of this syndrome
after any surgical procedure was not described previously. The first sign of
trouble in this case was significant cerebellar swelling. The reason for this
event is unclear. If the severe hypertension occurred sometime after the swelling had started, then one might consider
other causes, such as temporary obstruction of the shunt, impaired venous
drainage, or an unrecognized ventilation problem. Fortunately, the authors
took the appropriate measures to treat
this problem, and the swelling resolved.
The preferential distribution of the lesions in the posterior brain region in
RPL is not well understood. Ay et al. (1)
reviewed the literature regarding this
question. The density of sympathetic innervation in the cerebral vasculature is
maximal in the internal carotid and anterior cerebral arterial territories. This
innervation decreases posteriorly and is
least in the basilar artery and its
branches. Ay et al. concluded that sympathetic vasoconstriction may be more
effective in protecting the anterior circulation from overperfusion in patients
with acute hypertension.
Robert G. Ojemann
Boston, Massachusetts
1. Ay H, Buonanno FS, Schaefer PW, Le DA, Wang
B, Gonzalez RG, Koroshetz WJ: Posterior leukoencephalopathy without severe hypertension:
Utility of diffusion-weighted MRI. Neurology
51:1369–1376, 1998.

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Neurosurgery, Vol. 49, No. 5, November 2001