Steven P. Meyers, Leon Barnes, MD
PhD, MD #{149} Laligam
N. Sekhar,
Chondrosarcomas MR Imaging
ofthe
mas
of the
size,
skull
base
reviewed
were
retrospec-
to characterize
location,
signal
intensity,
were
obtained
tumorous erosion.
On
short
D. Curtin, MD
Sen,
Skull
Base:
and
repetition
of the skull base are rare, slow-growing, locally invasive tumors (1-7). These neo-
and
conventional
intra-
bone
has
are
generally
insensitive
radiation
been
reported
that
ment much
requires tumor
surgical as possible
nostic
imaging
of these
therefore
important
assessment
therapy,
and
effective
treat-
resection of as (8,9). Diagtumors
is
for preoperative
of tumor
bulk
and
the
har, and
MR images
was seen
mors
and
extension of these tumors on both unenhanced MR images and those enhanced with gadopentetate dimeglumine.
(59%)
was
in 10 of 17 tucaused
by matrix
fibrocartilaginous
elements, or both. Matrix mineralizalion was demonstrated with CT in seven of the 16 chondrosarcomas. Chondrosarcomas showed marked enhancement after administration of gadopentetate dimeglumine in either a heterogeneous (n = 8) or homogeneous (n = 3) pattern. The information about the size and extent of these neoplasms was important in the choice of surgical approaches for gross
total
Index
resection
terms:
Magnetic
of tumor. resonance
(MR), treat-
bone
sarcomas intensity
PATIENTS
nation gery.
1 7 chondrosarcomas
Computed
tomographic
obtained
for comparison
(mean years). tial
12,
requested December 26; revision ruary 13, 1992; accepted March
print
requests
RSNA, See also and article sue.
1991;
revision
received 2. Address
Febre-
to HOC.
1992 the editorial by Yousem by Sigal et al (pp 95-101)
group
consisted
nine men
age, 43 years; Eight patients
underwent surgical
recurrent (mean,
8.9 years)
after
radiation
tient
40 Gy
aging;
received
surgery the
before tient,
sarcoma
was
means
before
radiation
therapy
imaged
In the
One
pa-
of ster-
50 Gy
residual,
surgery.
therapy: by
MR imby
means
2 months
resected
was
performed
two patients,
at 1.5 T in
patient,
0.5
T in
and 0.35 T in one patient.
Multisection spin-echo (SE) pulse sequences were used in all MR studies as follows: short repetition time (TR)/echo time (TE) (TR msec/TE msec = 400-800/ 20-30)
sequences
and
TE/second-echo 75-iOO) sequences.
tamed
long
TR/first-echo
TE (2,000-3,200/25-30/ MR images were
in the axial and sagittal
patients patients. with
and in the coronal MR images were an
intersection
gap
ob-
planes
in all
plane in most 3-5 mm thick, of 1.0-2.5
The acquisition matrix varied 128to256 x 256. MR imaging was performed
mm.
from 256 x after
intra-
histologic and
examination
in seven
in four pa-
patients
with
recur-
in the coronal
plane
In all MR images, (5P.M., sity
W.L.H.)
of each
were
in most
assessed
tumor
categorized
patients.
two of the authors by
the
signal
consensus.
hypo-,
inten-
Tumors
iso-, or hyperin-
tense to muscle tissue and gray matter in the field of view. Signal from the tumor was classified homogeneous or heterogeneous on long TR/TE images. The dimensions,
centerpoint,
tumor were hancement
and
extension
of each
determined. The overall enpattern of each tumor was
homogeneous
(Fig i) or heteroge-
(Figs 2, 3). The degree to which the enhanced was qualitatively asas minimal (1 +), intermediate (2+)
sessed (Fig 3), or marked
(3+)
The T2 relaxation
(Figs
times
imaged
1, 2).
of seven
chon-
at 1.5 T were
calcu-
lated with the software program of the MR imager (Signa; GE Medical Systems, Milwaukee). Regions of interest within each tumor were drawn to eliminate the effects structures.
of volume
averaging
At least
five
with
adjacent
measurements
of
7 years
remaining
low-grade
surgically
1.0 T in one
drosarcomas
years
initial
received
MR imaging.
with
also underwent
i8 months
other
a large,
2.5-19.0 the
patients
postoperative
patients
chondrosarcomas
MR imaging
were
MR imaging 13 patients,
neous tumors
mi-
before
Eight
it
graded
years
age, 42 chondrosar-
MR imaging
Two of these
eotactic
22-69
median with
or residual
underwent
of eight
aged
diagnosis.
of conventional (pp 25-26) in this is-
were
MR images
in 16 patients.
coma
November
at sur-
(CT) scans
lesions
patients
chondrosarco-
after MR imaging.
and
subclassified
with
the
In all of the
or residual
rent or residual tumor). Short TR/TE (500800/20-30) MR images were obtained in the sagittal and axial planes in all patients
16 of the
were
mas,
tients,
(grade i, n = 14; grade 2, one, a dedifferentiated type.
conventional n = 2), and
Radiology
Received
removed
recurrent
(before
was exami-
examination,
resection.
with
venous administration of gadopentetate dimeglumine (0.1 mmol/kg) in 11 patients
METHODS
of the specimens
and
15213.
the signal location, and
AND
At histologic
study
From the Departments of Radiology (5P.M., W.L.H., H.D.C.), Pathology (LB.), and Neurosurgery (L.N.S., CS.), University of Pittsburgh School of Medicine, Presbyterian-University Hospital, DeSoto at O’Hara St. Pittsburgh, PA
reviewed the (MR) images obwith chondro-
The diagnosis of chondrosarcoma established by means of histologic
Our
I
(8).
to characterize and the size,
women
184:103-108
structures
We retrospectively magnetic resonance tamed in 17 patients
ment planning #{149} Sarcoma, 12.3211 #{149} Skull, CT, 12.1211 #{149} Skull, MR. 12.1214 #{149} Skull, primary neoplasms, 12.3211 1992;
an-
atomic relationship between tumor extension and adjacent neural, vascu-
time
surgical
to
(TR)/echo time (TE) MR images, chondrosarcomas generally had low to intermediate signal intensity; on long TR/TE MR images, they generally had very high signal intensity. Signal heterogeneity on long TR/TE
mineralization,
MD
HONDROSARCOMAS
plasms
to evaluate
mineralization
C
the
extension of these tumors. Eleven patients with chondrosarcomas received intravenously administered gadopentetate dimeglumine. In 16 patients, computed tomographic (CT) scans
#{149} Hugh
Features’
The magnetic resonance (MR) images from 17 patients with chondrosarcotively
L. Hirsch, Jr. MD MD #{149} Chandranath
#{149} William
pachondro-
after
partial
Abbreviations: SE time, TR = repetition
=
spin
echo,
TE
=
echo
time.
103
the
T2 relaxation
times
averaged
in each
standard
errors
of the seven Ti relaxation mined
were
tumor. of the
tumors times
because
and
mean
and
T2 relaxation
were could
none
obtained
The
times
calculated. The not be deter-
of the
MR
studies
required two pulse sequences with different TRs and the same TEs. CT was performed with third-generation
scanners.
Tumors
were
evaluated
for
evidence of (a) erosion, destruction bone, or both and (b) mineralization the
tumor
of
of
matrix.
RESULTS Size and Configuration Chondrosarcomas The size aged before 2.8 cm
of imfrom
x 2.0 x 2.0 cm to 5.3 x 6.5 x 5.5 (mean
size,
3.7
x 3.9
x 3.4 cm).
The size of recurrent and chondrosarcomas ranged 2.0
x 2.5
(mean
cm
size,
borders
residual from 2.0 x
x 8.0 x 7.2 cm
to 6.0
3.9 x 4.4 x 4.4 cm).
were
multilobulated
Tumor
and
well
defined except at sites of marrow vasion, where the margins were ill defined (Figs 1, 2, 4, 5). Signal Characteristics Chondrosarcomas On short drosarcomas termediate 5). One
inoften
of
TR/TE MR images, chongenerally had low to insignal intensity (Figs 1-3,
chondrosarcoma
imaged
prior
to surgery had a large zone of very high signal intensity, which corresponded to gross and histopathologic findings
of hemorrhage
within
intensity
within
nonminerahized
had signal por-
tions of the tumors on long TR/short TE and long TR/TE MR images, respectively (Figs 1-5). Signal heterogeneity
on
long
present signal
TR/TE
MR
images
in 10 of 17 tumors heterogeneity
was
(59%). caused
relative matter
recurrent
tumors
mean]). between
and
msec
T2 Relaxation
The calculated of chondrosarcomas 104
#{149} Radiology
T2 relaxation ranged
times from 89
(mean ±10
and
posteriorly
error
No difference the T2 values four
Findings after Enhancement Eleven
imaged recurrent
after
material.
prior to surtumors,
two lesions and those
into the prepontine
cistern
grade 1 chondrosarsurgery. (a) Short anteriorly into
(arrow).
the
(b) Short
with mawithout
tion
of tumor
enhancement thirds in all
overall
volume
that
enhancement
tumors patients neous Areas
showed
was greater than twoii patients (Figs 1, 2). The
pattern
of the
was heterogeneous in eight (73%) (Figs 2, 3) and homogein three patients (27%) (Fig 1). of diminished enhancement
often corresponded to sites of matrix mineralization depicted on CT scans (Fig
Contrast
underwent
and
time, of the
was observed of the three
of 17 patients
sarcomas
which tively
T2 relaxation
[standard
nor between the trix mineralization mineralization.
before
Times
aged
39 years with a conventional, with MR imaging 9 years after initial obtained at 1.5 T shows tumor extending
examination MR image
(arrowhead)
chondrosarcomas gery and the
contrast
Calculated
a woman
axial MR image obtained at 1.5 T shows tumor centered near the left petrooccipital junction, with anterior extension into the sphenoid sinus (arrowheads), posterior extension into the prepontine cistern (solid arrow), and lateral extension into the middle cranial fossa. Tumor displaces and partially encases the internal carotid artery (open arrow). (c) Postcontrast, short TR/TE (600/20), axial MR image shows marked homogeneous enhancement of tumor. (d) Long TR/TE (2,850/80) axial MR image shows that the tumor has predominant signal hyperintensity compared with signal intensity of adjacent gray matter. CT scans (not shown) showed no evidence of matrix mineralization within the tumor.
by
surgery.
from
underwent (600/20) sagittal
120
in signal intensity chardemonstrated between before
who
to 161 msec
areas on histopathin three cases. Comintensity of tumor
or residual imaged
coma TR/TE
MR images
The
to that of muscle and gray are summarized in the Table.
No difference acteristics was
1.
Figure
was
intratumorous zones of low signal intensity that corresponded to sites of chondroid mineralization detected on CT scans in seven cases (Figs 2, 5) and fibrocartilaginous ologic specimens parisons of signal
d.
C.
sphenoid sinus TR/TE (600/20)
the
tumor (Fig 4). Chondrosarcomas moderately high and very high
those
b.
a.
of chondrosarcomas surgery ranged
with
chondro-
examination
administration The
tumors enhanced considered marked
degree
of to
was qualita(3+) in 10
patients (Figs 1, 2) and intermediate (2+) in one patient (Fig 3). The frac-
2).
Location and Chondrosarcomas The
origination
center
Extension points
sites
and
of the
of probable
17 chondrosar-
comas of the skull base were located at or very near the petrooccipital synchondrosis (n = 13) (Figs 1, 3-5); endocranial surface of the sphenoid por-
July 1992
b.
C.
Figure with
2.
Images
from
a conventional,
a man
grade
aged
42 years
1 chondrosar-
coma who underwent examination with MR imaging before initial surgery. (a) Short TR/TE (600/20) sagittal MR image obtained at 1.5 T shows
clivus
near
that
sinus
with anterior (arrowhead)
with
compression
sis,
(arrow). image
the
(ta)
extension die cranial
tion of the chivus of the sella turcica moidal junction of the sphenoid and vomer (n =
(n
1) (Fig 2); region 1); sphenoeth(n = 1); and junction bone, ethmoid bone, 1). In 14 of the 17 =
(n
chondrosarcomas
=
(82%),
the
center
points of the lesions were off midline. The off-midline tumors included the 13 lesions at the petrooccipital synchondrosis (Figs 1, 3-5) and one at the sphenoethmoidal synchondrosis. The three other chondrosarcomas (18%) were midline lesions that on preoperative MR images involved the sphenoethmoidal junction, sella turcica, and endocranial surface of the sphenoid portion of the clivus (Fig 2). The latter two midline lesions were both located near the sphenooccipital synchondrosis
(Fig
2).
MR images showed extension of tumor into one cavernous sinus (n = 12) or both cavernous sinuses (n = 2) (Figs 1-3), sphenoidal sinus (i 6) (Figs 1, 2), ethmoidal air cells
= = 3), suprasellar (ii = 1),
10) (Fig 2), 4), orbits nasopharynx (ii = 5), prestybid (,i = 2) and/or poststyloid (n = 6) parapharyngeal space, hypoglossal canal (ii = 5), jugular foramen (z = 5), and prevertebral space (iz = 1). There (?1
Volume
sella
184
turcica cistern
#{149} Number
(?i
(i
=
=
1
was
no
along
evidence
the
comas
of the
the middle tients
of tumor
cranial
and
six patients
skull
tial
extended
fossa
the
(Figs
cranial fossa. MR tumor displacement of arteries
as a vertebral
artery
(n
in
of the into
vertebral artery (i = 1), (n = 1), internal carotid or both internal carotid (n = 1) (Figs 1-3). Tumor to completely surround
pa-
fossa
None
extended
encasement
into
in five
posterior
1-4).
chondrosarcomas
anterior vealed
Chondrosar-
base
cranial into
extension
nerves.
the
images and
repar-
such
as a
basilar artery artery (ii = 6), arteries was shown arteries such =
1), one
inter-
nal carotid artery (ii = 8), or both internah carotid arteries (n = 1). Only one tumor-encased artery had resultant luminal narrowing. Tumor borders
were
well
defined
on
MR
the sphenoid extension
and
midbrain
TRITE (600/20) axial at 1.5 T shows that the
with sinus
MR tumor
anterior extension (arrowhead), lateral
into the cavernous fossa (open arrow),
extension
with
midbrain TRITE
(solid
tumor. to the tumor. image
the
synchondro-
of the pons
Short
obtained
sinus and midand posterior compression of the pons and arrow). (c) Postcontrast short axial MR image shows
(600/20)
marked
invades
extension into and posterior
invades the clivus, into the sphenoid
e.
tumor
the sphenooccipital
(3+)
heterogeneous
enhancement
of
The basilar artery (arrow) is displaced right and is partially encased by the (d) Long TR/TE (2,300/80) axial MR shows heterogeneity and predomi-
nant hyperintensity of signal from lesion compared with intensity of signal from muscle and arcuate within
gray and the
matter. (e) Axial CT scan ring-shaped mineralization tumor
(arrows).
ease. Thirty months after surgery, this single patient went an MR examination showed a single metastatic
within
the brain
as a locally lesions
the initial underthat lesion
parenchyma
recurrent
petrooccipital
shows
as well
tumor
at the
synchondrosis.
showed
an
Both
intermediate
degree of heterogeneous ment with gadolinium
(2+)
enhance(Fig 3).
images,
except at sites of marrow invasion where tumor margins were irregular and indistinct. MR images depicted tumor invasion of marrow of the clivus (n = 15), petrous bone (a = 14), and occipital condyles (n = 4). Erosive or destructive bone changes were depicted on CT scans in all 16 patients who underwent CT. Only one patient in our series had imaging evidence of metastatic dis-
DISCUSSION Chondrosarcomas constitute approximately 11% of all malignant bone tumors (3). Chondrosarcomas of the skull base are rare lesions (1,2,3,5-7,10). In a study 6.7%
of 358 of
these
chondrosarcomas, tumors
head or neck (2). Chondrosarcomas rized
into
conventional,
histologic
only
occurred
have
been
subtypes
mesenchymal,
in
the
categosuch
and Radiology
as
dedif#{149} 105
a.
b.
C.
3. MR images obtained 30 months after initial surgical resection from a woman aged 69 years with a locally recurrent chondrosarcoma (conventional type, grade 2). (a) Precontrast, short TR/TE (650/20), axial MR image shows a recurrent tumor at the right petrooccipital synchondrosis (arrows). (b) Postcontrast, short TR/TE (650/20), axial MR image shows an intermediate (2+) degree of heterogeneous enhancement within the tumor (arrows), which partially encases the internal carotid artery (arrowhead). (c) Postcontrast, short TR/TE (650/20), coronal MR image shows an enhancing metastatic lesion (arrows) in the right frontoparietal region and locally recurrent tumor (arrowheads). Figure
b.
a. Figure
4.
MR images
obtained
before
C.
43 years with a conventional, grade 1 chondrosarcoma. (a) Short TR/TE (650/30) sagittal MR image obtained at 0.5 T shows an off-midline tumor, the superior portion of which contains a large zone of signal hyperintensity (arrows) that represents a hemorrhagic component. (b) This long TR/TE (2,100/100) axial MR image was obtained through the nonhemorrhagic portion of the tumor (arrows), which is centered near the petrooccipital junction. (c) This long TR/TE (2,100/100) axial MR image was obtained through the hemorrhagic portion of the tumor that extends into the middle cranial fossa. Both hemorrhagic and nonhemorrhagic
components
of the
tumor
initial
have
surgery
from
heterogeneous,
most
comform, grades
islands
1-4
nuclear
ferentiated
on
the
basis
of cellularity,
Some
and
authors,
mitotic
however,
rate
(2,11).
recognize
only
three grades (12). At histologic examination, conventional chondrosarcomas contain many round or oval cartilaginous
cells
nuclei
with
(1-3).
usually
single The
causes
large
or
multiple
conventional morbidity
subtype by
tumor
inva-
sion and destruction of local structures over long periods of time (8,13). Dedifferentiated and mesenchymal chondrosarcomas with
are poorer
ventional
more prognoses
subtype.
chondrosarcomas
in which present 106
aggressive
highly within
#{149} Radiology
than
lesions the
a group
anaplastic a low-grade
nous
tumor
At
signal
of cartilage
mes-
sheets
stromal
nuclei
chondrosarcomas
on b and
contain
and
small
intensity
microscopy,
chondrosarcomas
perchromatic
cells
(1,2,11). in
this
per-
intensity
and
or isointense
hypointense
hy-
the
17
16 were
slightly
to gray
iso-
On
evalua-
matter.
of lesions
signal
that
hemorrhage,
contained which
a large was
hyperintensity
obtained
before
obtained
with
surgery.
long
zone
a large
on
TR/short
tics.
area
and on
skull
the
They
were
high
predomi-
usually
their
of
high,
MR
image
intensity
On
MR
images
skull clearly
cellular
chronic had
both
was three
low,
signal intermediate,
The
(14).
high
of chondrosarcomas base
on
long
an exception
low because
inflammatory
nonhomogeneous
all
short
malignant
composition,
benign
that or
on
had homogeneous signal intensity
highly
lesions intensity
that,
characteris-
TR MR images,
to intermediate whereas
be differen-
could
of signal
reported
tumors
of
base
basis
long
the
TE and
had
generally
and
TR and
of
we chondro-
chondrosarco-
base
hyperintense to muscle and gray matter. Som et al (14) proposed that benign and malignant lesions that involve the tiated
or
sequences, skull
intensity
sinuses
hy-
and
tion of the resected specimens, found only one conventional
of the
nantly
series,
were
TR/TE
mas
with Of
to muscle
long signal
conventional subtype and one was dedifferentiated. On MR images obtained with short TR/TE sequences, chondrosarcomas generally had low to intermediate
signal
c.
of undif-
of the
sarcoma
foci are cartilagi-
high
(3,13).
enchymal
con-
Dedifferentiated are
aged
predominantly
ferentiated forms (10,11). The mon subtype is the conventional which can be subdivided into pleomorphism,
a woman
TRITE
to this
signal of the
images
is
finding. July
1992
Figure
5.
Images obtained 19 years after initial surgical resection from a man aged 41 years with a recurrent chondrosarcoma (conventional 1). (a) Long TR/TE (2,500/90) axial MR image obtained at 1.5 T shows a large tumor with heterogeneous signal intensity centered at the petrooccipital junction (arrow). (b) Axial CT scan shows that the tumor contains prominent chondroid mineralization (arrow), which corresponds in location to areas of signal hypointensity on a. (c) Coronal CT scan shows the location of the petrooccipital synchondrosis (arrow) in relation to the tumor. type,
grade
vious
small
studies
sarcomas
clinical site
of cranial
reported
MR
of
imaging,
tumor
chondro-
before
the
the
was
the
advent
most
of
frequent
parasellar
region;
the next most frequent, the region of the cerebellopontine angle (5). Cranial chondrosarcomas within
almost
the
believed chondral
base;
In
our
center
cipital
study,
points
sphenooccipital
located drosis,
in
of the tumors
10
patients
of chondrosarimages was seen
(59%),
it corresponded
of prominent tion depicted other cases,
trix mineralization the 15 conventional tion
with
was
CT.
No
depicted
position
most patients, throughout erogeneous images
fibrocartilagitumors. Ma-
matrix
with
mineraliza-
CT in the single
characteristics
in was
intensity
observed
sigto
without matrix mineralization. The nal characteristics of chondrosarcomas of the skull base are similar to those
sig-
within
the
to fatty
marrow
defined
on postcontrast
appendicular
on
skeleton
how
To our
knowledge,
the characteristics
of skull-base
chondrosarcomas
hanced
with
gadolinium
Volume
184
#{149} Number
en-
have 1
not been
delay
of contrast
aging
might
affect
cartilaginous
bone,
or
ally
contain
adminis-
tissues
of radiation
degeneration
such
as osteochondromas
extent,
do
(1,2,5,6,13).
usu-
exposure of benign
or malig(3,13).
In
pre-
at
and
diagnostic
con-
have
of
Most
off-midline
the
chondrocenter
points,
long
TR/TE
MR images
(4,16).
subgroups
of
The
range
of T2 values
mas
in our
study
ported
in both
(16,17).
These
relaxation
overlapped
chordoma findings
parameters times
those
re-
subgroups suggest that such
have
chordomas.
of chondrosarco-
as Ti
limited
and
useful-
in the distinction between the two types of skull-base tumors. Whenever present, prominent chondroid-type mineralization occurs within chondrosarcomas and not within the chordomas ness
as
lesions
the other
rests
whereas most chordomas are located in the midline (16). Both tumors can have very high signal intensity on unen-
T2
In ad-
can develop
that
likely
chondrosarconlas
is chordoma.
quantitative
not
and
base
differential
conventional im-
endochondral
that
cartilage
nant
MR
suture
Sze et al (17) reported that calculated Ti and T2 relaxation times could be used to distinguish between the chondroid and
after adminlt is therefore and
base
skull
was
suggest
cartilaginous
with
hanced
All study
enhancement. can arise directly
chondrosarcomas
a result
skull
less well
degree,
one
synchondrosis
main
sarcomas
images.
tissue,
other
to
images
between the
The
four other near the
synchonsynchondro-
findings
of the from
sideration
next
in our
material
pattern of tumor Chondrosarcomas
dition,
(15).
images
tumors
petrooccipital synchondroses.
mar-
generally
These
originate
paren-
MR
the petrooc-
synchondrosis,
vomer.
is
17 lesions
Of the points
at the sphenoethmoid and one was at the
these
tissue
margins
MR
MR
tration
from
lo-
were
unenhanced
unknown
and
brain
tumor
obtained immediately of gadolinium.
istration
tumor enhanced
than
However,
were
and those single de-
differentiated chondrosarcoma had nal characteristics generally similar those of conventional chondrosarconlas
cated
degree
chyma.
In
in a hetMR
neural
rosarcomas
postcontrast
between
or residual tumors before surgery. The
a greater
the
was seen
define
to adjacent
chond
than
MR signal
helped
relative
because
of
enhancement
13 of
at or near
sis of the sphenoethrnoidal
Chondrosarcomas
most of each tumor pattern. Postcontrast often
gins
chondrosarcoma.
difference
recurrent imaged
to the
was seen in seven chondrosarcomas
dedifferentiated No
in seven
reported.
showed a marked degree of contrast enhancement in nearly all patients.
coarse matrix nlineralizaon CT scans. In three the signal heterogeneity
was caused by prominent nous elements within the
imaged
and
previously
occur
occurrence
to the endobone structures
synchondrosis. two had center
lesions,
Signal heterogeneity comas on long TR/TE
always this
to be secondary origin of these
(5,6,13).
had
skull
Radiology
#{149} 107
reported
in the radiology
literature
tients
(4,16,18). Differentiation between chordoma and chondrosarcoma is often based on histologic analysis and immu-
nohistochemical staining. cific for ectoderm-derived as epithelial
atins,
membrane
are
positive
in chordomas
cases,
and
not
chondrosarcomas
(10,13). Other common also be included in the nosis with chondrosarcomas
and
spesuch and ker-
antigen
in mesoderm-derived
gioma
Markers tumors,
metastatic
differentiation
tumors that can differential diagare menin-
lesions.
In many
of these
diagnostic
entities that is based solely on MR imaging and CT characteristics may be impossible.
However,
a heterogeneously
enhanced tumor located at the petrooccipital synchondrosis that has high signal intensity on long TR/TE images, contains chondroid mineralization, and is associated with erosive bone changes strongly favors the diagnosis of chondrosarcoma. Gross total resection of tumor has
been
reported
treatment
skull
to be the most
for
chondrosarcomas
base
(8,19,20).
It is crucial
the extent
of these
tumors
select the best surgical resection of as much (8,19,20). MR imaging
effective of the to define
in order
to
approaches for tumor as possible has been reported
to be superior to CT for evaluation of the extent of skull-base neoplasms because it has greater contrast resolution and because beam-hardening artifacts affect CT (4,8). However, CT was proved superior to MR imaging in detection of tumorous mineralization and bone erosion (4). Surgeons
imaging tween normal (8,19,20).
near
at our
institution
use
MR
to define
the relationship beextension of tumor to adjacent soft tissues and blood vessels Resection
the internal
cause permanent (8). To determine risk for neurologic
of chondrosarcomas
carotid
artery
can
occlusion of this vessel which patients are at injury due to perma-
nent arterial occlusion, occlusion of the internal carotid artery with the intraluminal balloon test is generally performed in conjunction with clinical evaluation
and
imaging
of cerebral
blood flow by means of CT scans enhanced with stable xenon (8,21). Pa-
at risk
reduced
for
neurologic
cerebral
dergo
blood
placement
injury
flow
of arterial
bypass
grafts to obviate this complication In addition to MR imaging and test occlusion studies, CT scans ally
obtained
to ascertain
2.
from
can un-
the
(8,21). balloon are usu-
extent
are
regionally
invasive
4.
of 5.
tumorous invasion of bone (8). MR imaging showed that chondrosarcomas
3.
tumors.
It
showed frequent tumor extension into the cavernous sinus, sella turcica, sphenoidal sinus, and parapharyngeal space. Development of new surgical ap-
6.
proaches
8.
to the
skull
base
has
7.
facilitated
radical resection of tumor (8,19,20). For resection of chondrosarcomas that invade the civus and extend into sphenoidal and ethmoidal sinuses, the basal subfrontal
approach
is an effective
tech-
sions
However, tumorous extenlateral to the petrous internal ca-
rotid
artery
nique
9.
10.
(8).
cannot
be reached
with
I I.
this
method (8,19). For these tumors, the subtemporal and preauricular infratemporal approach can be used (8,19,20). Whenever
and and the
chondrosarcomas
are
invade the civus, petrous sphenoidal and ethmoidal subfrontal
poral
transbasal
approaches
(8,19,20).
12.
large
13.
bone, sinuses,
and
diagnosis,
infratem-
14.
are combined
In many
cases,
removal
of tu-
mor with these methods can be performed extradurally (8,19,20). However, whenever chondrosarcomas invade the
15.
superior into the
16.
sinus,
sphenoidal suprasellar
or both,
used
to supplement
an
civus cistern,
and extend cavernous
intradural
the
approach
main
is
extradural
part of the procedure (8,19,20). Gross total tumor resection and adjuvant, precision, high-dose radiation therapy for residual tumors after surgical debulking have produced encouraging preliminary results (9,22). Determination of the efficacy
of these
methods
in the
cure
long-term control of chondrosarcomas will require adequate follow-up (8).
Pritchard Di, Lunke RJ, Taylor WF, Dahlin DC, Medley BE. Chondrosarcoma: a clinicopathologic and statistical analysis. Cancer 1980; 45: 149-157. Dahlin DC, Unni KK. Chondrosarcomas. In: Bone tumors. 4th ed. Springfield, Ill: Thomas, 1986; 227-268. Oot RF, Melville GE, New PFJ, et al. The role of MR and CT in evaluating clival chordomas and chondrosarcomas. AIR 1988; 151:567-575. Grossman RI, Davis KR. Cranial computed tomographic appearance of chondrosarcoma of the base of the skull. Radiology 1981; 141: 403-408. Bahr AL, Gayler BW. Cranial chondrosarcomas. Radiology 1977; 124:151-156. Cianfrigiia F,Pompili A, Occhipinti E. Intracranial malignant cartilaginous tumors: report of two cases and review of literature. Acta Neurochir 1978; 45:163-175. Sen CN, Sekhar UN, Schramm VL,Janecka IP. Chordoma and chondrosarcoma of the cranial base: an 8-year experience. Neurosurgery 1989; 25:931-941. Suit HO, Goitein M, Munzenrider J, et al. Definitive radiation therapy for chordoma and chondrosarcoma of base of skull and cervical spine. J Neurosurg 1982; 56:377-385. Barnes U. Pathobiology of selected tumors of the base of the skull. Skull Base Surg 1991; 1:207-216. Lee YY, Van Tassel P. Craniofacial chondrosarcomas: imaging findings in 15 untreated cases. AJNR 1989; 10:165-470. Evans HU, Ayala AG, Romsdahl MM. Prognostic factors in chondrosarcoma of bone: a clinicopathologic analysis with emphasis on histologic grading. Cancer 1977; 40:818-831. Huvos AG. Chondrosarcomas of the craniofacial bones. In: Mitchell J, ed. Bone tumors:
or
17. 18. 19.
ral-infratemporal
20. U 21.
Acknowledgments: The authors thank Douglas Kondziolka, MD, and L. Dade Lunsford, MD, for contributing case materials, and Kathryn Frazier for assistance in the preparation of our
manuscript.
treatment
and
prognosis.
2nd
approach
to extensive
cra-
nial base tumours. Acta Neurochir (Wein) 1988; 92:83-92. Sekhar UN, Schramm VU Jr,Jones NF. Subtemporal-preauricular infratemporal fossa approach to large lateral and posterior cranial base neoplasms. J Neurosurg 1987; 67:488-499. Erba
SM,
Horton
JA, Latchaw
RE, et at.
loon test occlusion of the internal carotid tery with xenon/CT cerebral blood flow ing. AJNR 1988; 9:35-38. 22.
ed.
Philadelphia: Saunders, 1991; 395-401. Som Ph’!, Dillon WP, Sze G, Lidov M, Biller HF, Lawson W. Benign and malignant sinonasal lesions with intracranial extension: differentiahon with MR imaging. Radiology 1989; 172: 763-766. Golifieri R, Baddeley H, PringleJS. Primary bone tumors: MR morphologic appearance correlated with pathologic examinations. Acta Radiol 1991; 32:290-298. Meyers SP, Hirsch WLJr, Curtin HD, Barnes U, Sekhar UN, Sen C. Magnetic resonance imaging features of chordomas of the skull base. AJNR (in press). Sze G, Uichanco US III, Brant-Zawadzki MN, et at. Chordomas: MR imaging. Radiology 1988; 166:187-191. Meyer JE, Oot RF, Lindfors KF. CT appearance of cival chordomas. J Comput Assist Tomogr 1986; 10:34-38. Sekhar UN, Janecka IP, Jones NF. Subtempo-
Austin-Seymour
M, Munzenrider
Bat-
arimag-
j, Goitein
M,
et at. Fractionated proton radiation therapy of chordoma and low-grade chondrosarcoma of the base of the skull. J Neurosurg 1989; 70: 13-17.
References 1.
Russell OS, Rubinstein U. Chondrosarcomas and chordomas. In: Russell OS, Rubinstein U, eds. Pathology of tumours of the nervous system. Baltimore: Williams & Wilkins, 1989; 819821.
108
#{149} Radiology
July 1992
PhD, MD #{149} Laligam
N. Sekhar,
Chondrosarcomas MR Imaging
ofthe
mas
of the
size,
skull
base
reviewed
were
retrospec-
to characterize
location,
signal
intensity,
were
obtained
tumorous erosion.
On
short
D. Curtin, MD
Sen,
Skull
Base:
and
repetition
of the skull base are rare, slow-growing, locally invasive tumors (1-7). These neo-
and
conventional
intra-
bone
has
are
generally
insensitive
radiation
been
reported
that
ment much
requires tumor
surgical as possible
nostic
imaging
of these
therefore
important
assessment
therapy,
and
effective
treat-
resection of as (8,9). Diagtumors
is
for preoperative
of tumor
bulk
and
the
har, and
MR images
was seen
mors
and
extension of these tumors on both unenhanced MR images and those enhanced with gadopentetate dimeglumine.
(59%)
was
in 10 of 17 tucaused
by matrix
fibrocartilaginous
elements, or both. Matrix mineralizalion was demonstrated with CT in seven of the 16 chondrosarcomas. Chondrosarcomas showed marked enhancement after administration of gadopentetate dimeglumine in either a heterogeneous (n = 8) or homogeneous (n = 3) pattern. The information about the size and extent of these neoplasms was important in the choice of surgical approaches for gross
total
Index
resection
terms:
Magnetic
of tumor. resonance
(MR), treat-
bone
sarcomas intensity
PATIENTS
nation gery.
1 7 chondrosarcomas
Computed
tomographic
obtained
for comparison
(mean years). tial
12,
requested December 26; revision ruary 13, 1992; accepted March
requests
RSNA, See also and article sue.
1991;
revision
received 2. Address
Febre-
to HOC.
1992 the editorial by Yousem by Sigal et al (pp 95-101)
group
consisted
nine men
age, 43 years; Eight patients
underwent surgical
recurrent (mean,
8.9 years)
after
radiation
tient
40 Gy
aging;
received
surgery the
before tient,
sarcoma
was
means
before
radiation
therapy
imaged
In the
One
pa-
of ster-
50 Gy
residual,
surgery.
therapy: by
MR imby
means
2 months
resected
was
performed
two patients,
at 1.5 T in
patient,
0.5
T in
and 0.35 T in one patient.
Multisection spin-echo (SE) pulse sequences were used in all MR studies as follows: short repetition time (TR)/echo time (TE) (TR msec/TE msec = 400-800/ 20-30)
sequences
and
TE/second-echo 75-iOO) sequences.
tamed
long
TR/first-echo
TE (2,000-3,200/25-30/ MR images were
in the axial and sagittal
patients patients. with
and in the coronal MR images were an
intersection
gap
ob-
planes
in all
plane in most 3-5 mm thick, of 1.0-2.5
The acquisition matrix varied 128to256 x 256. MR imaging was performed
mm.
from 256 x after
intra-
histologic and
examination
in seven
in four pa-
patients
with
recur-
in the coronal
plane
In all MR images, (5P.M., sity
W.L.H.)
of each
were
in most
assessed
tumor
categorized
patients.
two of the authors by
the
signal
consensus.
hypo-,
inten-
Tumors
iso-, or hyperin-
tense to muscle tissue and gray matter in the field of view. Signal from the tumor was classified homogeneous or heterogeneous on long TR/TE images. The dimensions,
centerpoint,
tumor were hancement
and
extension
of each
determined. The overall enpattern of each tumor was
homogeneous
(Fig i) or heteroge-
(Figs 2, 3). The degree to which the enhanced was qualitatively asas minimal (1 +), intermediate (2+)
sessed (Fig 3), or marked
(3+)
The T2 relaxation
(Figs
times
imaged
1, 2).
of seven
chon-
at 1.5 T were
calcu-
lated with the software program of the MR imager (Signa; GE Medical Systems, Milwaukee). Regions of interest within each tumor were drawn to eliminate the effects structures.
of volume
averaging
At least
five
with
adjacent
measurements
of
7 years
remaining
low-grade
surgically
1.0 T in one
drosarcomas
years
initial
received
MR imaging.
with
also underwent
i8 months
other
a large,
2.5-19.0 the
patients
postoperative
patients
chondrosarcomas
MR imaging
were
MR imaging 13 patients,
neous tumors
mi-
before
Eight
it
graded
years
age, 42 chondrosar-
MR imaging
Two of these
eotactic
22-69
median with
or residual
underwent
of eight
aged
diagnosis.
of conventional (pp 25-26) in this is-
were
MR images
in 16 patients.
coma
November
at sur-
(CT) scans
lesions
patients
chondrosarco-
after MR imaging.
and
subclassified
with
the
In all of the
or residual
rent or residual tumor). Short TR/TE (500800/20-30) MR images were obtained in the sagittal and axial planes in all patients
16 of the
were
mas,
tients,
(grade i, n = 14; grade 2, one, a dedifferentiated type.
conventional n = 2), and
Radiology
Received
removed
recurrent
(before
was exami-
examination,
resection.
with
venous administration of gadopentetate dimeglumine (0.1 mmol/kg) in 11 patients
METHODS
of the specimens
and
15213.
the signal location, and
AND
At histologic
study
From the Departments of Radiology (5P.M., W.L.H., H.D.C.), Pathology (LB.), and Neurosurgery (L.N.S., CS.), University of Pittsburgh School of Medicine, Presbyterian-University Hospital, DeSoto at O’Hara St. Pittsburgh, PA
reviewed the (MR) images obwith chondro-
The diagnosis of chondrosarcoma established by means of histologic
Our
I
(8).
to characterize and the size,
women
184:103-108
structures
We retrospectively magnetic resonance tamed in 17 patients
ment planning #{149} Sarcoma, 12.3211 #{149} Skull, CT, 12.1211 #{149} Skull, MR. 12.1214 #{149} Skull, primary neoplasms, 12.3211 1992;
an-
atomic relationship between tumor extension and adjacent neural, vascu-
time
surgical
to
(TR)/echo time (TE) MR images, chondrosarcomas generally had low to intermediate signal intensity; on long TR/TE MR images, they generally had very high signal intensity. Signal heterogeneity on long TR/TE
mineralization,
MD
HONDROSARCOMAS
plasms
to evaluate
mineralization
C
the
extension of these tumors. Eleven patients with chondrosarcomas received intravenously administered gadopentetate dimeglumine. In 16 patients, computed tomographic (CT) scans
#{149} Hugh
Features’
The magnetic resonance (MR) images from 17 patients with chondrosarcotively
L. Hirsch, Jr. MD MD #{149} Chandranath
#{149} William
pachondro-
after
partial
Abbreviations: SE time, TR = repetition
=
spin
echo,
TE
=
echo
time.
103
the
T2 relaxation
times
averaged
in each
standard
errors
of the seven Ti relaxation mined
were
tumor. of the
tumors times
because
and
mean
and
T2 relaxation
were could
none
obtained
The
times
calculated. The not be deter-
of the
MR
studies
required two pulse sequences with different TRs and the same TEs. CT was performed with third-generation
scanners.
Tumors
were
evaluated
for
evidence of (a) erosion, destruction bone, or both and (b) mineralization the
tumor
of
of
matrix.
RESULTS Size and Configuration Chondrosarcomas The size aged before 2.8 cm
of imfrom
x 2.0 x 2.0 cm to 5.3 x 6.5 x 5.5 (mean
size,
3.7
x 3.9
x 3.4 cm).
The size of recurrent and chondrosarcomas ranged 2.0
x 2.5
(mean
cm
size,
borders
residual from 2.0 x
x 8.0 x 7.2 cm
to 6.0
3.9 x 4.4 x 4.4 cm).
were
multilobulated
Tumor
and
well
defined except at sites of marrow vasion, where the margins were ill defined (Figs 1, 2, 4, 5). Signal Characteristics Chondrosarcomas On short drosarcomas termediate 5). One
inoften
of
TR/TE MR images, chongenerally had low to insignal intensity (Figs 1-3,
chondrosarcoma
imaged
prior
to surgery had a large zone of very high signal intensity, which corresponded to gross and histopathologic findings
of hemorrhage
within
intensity
within
nonminerahized
had signal por-
tions of the tumors on long TR/short TE and long TR/TE MR images, respectively (Figs 1-5). Signal heterogeneity
on
long
present signal
TR/TE
MR
images
in 10 of 17 tumors heterogeneity
was
(59%). caused
relative matter
recurrent
tumors
mean]). between
and
msec
T2 Relaxation
The calculated of chondrosarcomas 104
#{149} Radiology
T2 relaxation ranged
times from 89
(mean ±10
and
posteriorly
error
No difference the T2 values four
Findings after Enhancement Eleven
imaged recurrent
after
material.
prior to surtumors,
two lesions and those
into the prepontine
cistern
grade 1 chondrosarsurgery. (a) Short anteriorly into
(arrow).
the
(b) Short
with mawithout
tion
of tumor
enhancement thirds in all
overall
volume
that
enhancement
tumors patients neous Areas
showed
was greater than twoii patients (Figs 1, 2). The
pattern
of the
was heterogeneous in eight (73%) (Figs 2, 3) and homogein three patients (27%) (Fig 1). of diminished enhancement
often corresponded to sites of matrix mineralization depicted on CT scans (Fig
Contrast
underwent
and
time, of the
was observed of the three
of 17 patients
sarcomas
which tively
T2 relaxation
[standard
nor between the trix mineralization mineralization.
before
Times
aged
39 years with a conventional, with MR imaging 9 years after initial obtained at 1.5 T shows tumor extending
examination MR image
(arrowhead)
chondrosarcomas gery and the
contrast
Calculated
a woman
axial MR image obtained at 1.5 T shows tumor centered near the left petrooccipital junction, with anterior extension into the sphenoid sinus (arrowheads), posterior extension into the prepontine cistern (solid arrow), and lateral extension into the middle cranial fossa. Tumor displaces and partially encases the internal carotid artery (open arrow). (c) Postcontrast, short TR/TE (600/20), axial MR image shows marked homogeneous enhancement of tumor. (d) Long TR/TE (2,850/80) axial MR image shows that the tumor has predominant signal hyperintensity compared with signal intensity of adjacent gray matter. CT scans (not shown) showed no evidence of matrix mineralization within the tumor.
by
surgery.
from
underwent (600/20) sagittal
120
in signal intensity chardemonstrated between before
who
to 161 msec
areas on histopathin three cases. Comintensity of tumor
or residual imaged
coma TR/TE
MR images
The
to that of muscle and gray are summarized in the Table.
No difference acteristics was
1.
Figure
was
intratumorous zones of low signal intensity that corresponded to sites of chondroid mineralization detected on CT scans in seven cases (Figs 2, 5) and fibrocartilaginous ologic specimens parisons of signal
d.
C.
sphenoid sinus TR/TE (600/20)
the
tumor (Fig 4). Chondrosarcomas moderately high and very high
those
b.
a.
of chondrosarcomas surgery ranged
with
chondro-
examination
administration The
tumors enhanced considered marked
degree
of to
was qualita(3+) in 10
patients (Figs 1, 2) and intermediate (2+) in one patient (Fig 3). The frac-
2).
Location and Chondrosarcomas The
origination
center
Extension points
sites
and
of the
of probable
17 chondrosar-
comas of the skull base were located at or very near the petrooccipital synchondrosis (n = 13) (Figs 1, 3-5); endocranial surface of the sphenoid por-
July 1992
b.
C.
Figure with
2.
Images
from
a conventional,
a man
grade
aged
42 years
1 chondrosar-
coma who underwent examination with MR imaging before initial surgery. (a) Short TR/TE (600/20) sagittal MR image obtained at 1.5 T shows
clivus
near
that
sinus
with anterior (arrowhead)
with
compression
sis,
(arrow). image
the
(ta)
extension die cranial
tion of the chivus of the sella turcica moidal junction of the sphenoid and vomer (n =
(n
1) (Fig 2); region 1); sphenoeth(n = 1); and junction bone, ethmoid bone, 1). In 14 of the 17 =
(n
chondrosarcomas
=
(82%),
the
center
points of the lesions were off midline. The off-midline tumors included the 13 lesions at the petrooccipital synchondrosis (Figs 1, 3-5) and one at the sphenoethmoidal synchondrosis. The three other chondrosarcomas (18%) were midline lesions that on preoperative MR images involved the sphenoethmoidal junction, sella turcica, and endocranial surface of the sphenoid portion of the clivus (Fig 2). The latter two midline lesions were both located near the sphenooccipital synchondrosis
(Fig
2).
MR images showed extension of tumor into one cavernous sinus (n = 12) or both cavernous sinuses (n = 2) (Figs 1-3), sphenoidal sinus (i 6) (Figs 1, 2), ethmoidal air cells
= = 3), suprasellar (ii = 1),
10) (Fig 2), 4), orbits nasopharynx (ii = 5), prestybid (,i = 2) and/or poststyloid (n = 6) parapharyngeal space, hypoglossal canal (ii = 5), jugular foramen (z = 5), and prevertebral space (iz = 1). There (?1
Volume
sella
184
turcica cistern
#{149} Number
(?i
(i
=
=
1
was
no
along
evidence
the
comas
of the
the middle tients
of tumor
cranial
and
six patients
skull
tial
extended
fossa
the
(Figs
cranial fossa. MR tumor displacement of arteries
as a vertebral
artery
(n
in
of the into
vertebral artery (i = 1), (n = 1), internal carotid or both internal carotid (n = 1) (Figs 1-3). Tumor to completely surround
pa-
fossa
None
extended
encasement
into
in five
posterior
1-4).
chondrosarcomas
anterior vealed
Chondrosar-
base
cranial into
extension
nerves.
the
images and
repar-
such
as a
basilar artery artery (ii = 6), arteries was shown arteries such =
1), one
inter-
nal carotid artery (ii = 8), or both internah carotid arteries (n = 1). Only one tumor-encased artery had resultant luminal narrowing. Tumor borders
were
well
defined
on
MR
the sphenoid extension
and
midbrain
TRITE (600/20) axial at 1.5 T shows that the
with sinus
MR tumor
anterior extension (arrowhead), lateral
into the cavernous fossa (open arrow),
extension
with
midbrain TRITE
(solid
tumor. to the tumor. image
the
synchondro-
of the pons
Short
obtained
sinus and midand posterior compression of the pons and arrow). (c) Postcontrast short axial MR image shows
(600/20)
marked
invades
extension into and posterior
invades the clivus, into the sphenoid
e.
tumor
the sphenooccipital
(3+)
heterogeneous
enhancement
of
The basilar artery (arrow) is displaced right and is partially encased by the (d) Long TR/TE (2,300/80) axial MR shows heterogeneity and predomi-
nant hyperintensity of signal from lesion compared with intensity of signal from muscle and arcuate within
gray and the
matter. (e) Axial CT scan ring-shaped mineralization tumor
(arrows).
ease. Thirty months after surgery, this single patient went an MR examination showed a single metastatic
within
the brain
as a locally lesions
the initial underthat lesion
parenchyma
recurrent
petrooccipital
shows
as well
tumor
at the
synchondrosis.
showed
an
Both
intermediate
degree of heterogeneous ment with gadolinium
(2+)
enhance(Fig 3).
images,
except at sites of marrow invasion where tumor margins were irregular and indistinct. MR images depicted tumor invasion of marrow of the clivus (n = 15), petrous bone (a = 14), and occipital condyles (n = 4). Erosive or destructive bone changes were depicted on CT scans in all 16 patients who underwent CT. Only one patient in our series had imaging evidence of metastatic dis-
DISCUSSION Chondrosarcomas constitute approximately 11% of all malignant bone tumors (3). Chondrosarcomas of the skull base are rare lesions (1,2,3,5-7,10). In a study 6.7%
of 358 of
these
chondrosarcomas, tumors
head or neck (2). Chondrosarcomas rized
into
conventional,
histologic
only
occurred
have
been
subtypes
mesenchymal,
in
the
categosuch
and Radiology
as
dedif#{149} 105
a.
b.
C.
3. MR images obtained 30 months after initial surgical resection from a woman aged 69 years with a locally recurrent chondrosarcoma (conventional type, grade 2). (a) Precontrast, short TR/TE (650/20), axial MR image shows a recurrent tumor at the right petrooccipital synchondrosis (arrows). (b) Postcontrast, short TR/TE (650/20), axial MR image shows an intermediate (2+) degree of heterogeneous enhancement within the tumor (arrows), which partially encases the internal carotid artery (arrowhead). (c) Postcontrast, short TR/TE (650/20), coronal MR image shows an enhancing metastatic lesion (arrows) in the right frontoparietal region and locally recurrent tumor (arrowheads). Figure
b.
a. Figure
4.
MR images
obtained
before
C.
43 years with a conventional, grade 1 chondrosarcoma. (a) Short TR/TE (650/30) sagittal MR image obtained at 0.5 T shows an off-midline tumor, the superior portion of which contains a large zone of signal hyperintensity (arrows) that represents a hemorrhagic component. (b) This long TR/TE (2,100/100) axial MR image was obtained through the nonhemorrhagic portion of the tumor (arrows), which is centered near the petrooccipital junction. (c) This long TR/TE (2,100/100) axial MR image was obtained through the hemorrhagic portion of the tumor that extends into the middle cranial fossa. Both hemorrhagic and nonhemorrhagic
components
of the
tumor
initial
have
surgery
from
heterogeneous,
most
comform, grades
islands
1-4
nuclear
ferentiated
on
the
basis
of cellularity,
Some
and
authors,
mitotic
however,
rate
(2,11).
recognize
only
three grades (12). At histologic examination, conventional chondrosarcomas contain many round or oval cartilaginous
cells
nuclei
with
(1-3).
usually
single The
causes
large
or
multiple
conventional morbidity
subtype by
tumor
inva-
sion and destruction of local structures over long periods of time (8,13). Dedifferentiated and mesenchymal chondrosarcomas with
are poorer
ventional
more prognoses
subtype.
chondrosarcomas
in which present 106
aggressive
highly within
#{149} Radiology
than
lesions the
a group
anaplastic a low-grade
nous
tumor
At
signal
of cartilage
mes-
sheets
stromal
nuclei
chondrosarcomas
on b and
contain
and
small
intensity
microscopy,
chondrosarcomas
perchromatic
cells
(1,2,11). in
this
per-
intensity
and
or isointense
hypointense
hy-
the
17
16 were
slightly
to gray
iso-
On
evalua-
matter.
of lesions
signal
that
hemorrhage,
contained which
a large was
hyperintensity
obtained
before
obtained
with
surgery.
long
zone
a large
on
TR/short
tics.
area
and on
skull
the
They
were
high
predomi-
usually
their
of
high,
MR
image
intensity
On
MR
images
skull clearly
cellular
chronic had
both
was three
low,
signal intermediate,
The
(14).
high
of chondrosarcomas base
on
long
an exception
low because
inflammatory
nonhomogeneous
all
short
malignant
composition,
benign
that or
on
had homogeneous signal intensity
highly
lesions intensity
that,
characteris-
TR MR images,
to intermediate whereas
be differen-
could
of signal
reported
tumors
of
base
basis
long
the
TE and
had
generally
and
TR and
of
we chondro-
chondrosarco-
base
hyperintense to muscle and gray matter. Som et al (14) proposed that benign and malignant lesions that involve the tiated
or
sequences, skull
intensity
sinuses
hy-
and
tion of the resected specimens, found only one conventional
of the
nantly
series,
were
TR/TE
mas
with Of
to muscle
long signal
conventional subtype and one was dedifferentiated. On MR images obtained with short TR/TE sequences, chondrosarcomas generally had low to intermediate
signal
c.
of undif-
of the
sarcoma
foci are cartilagi-
high
(3,13).
enchymal
con-
Dedifferentiated are
aged
predominantly
ferentiated forms (10,11). The mon subtype is the conventional which can be subdivided into pleomorphism,
a woman
TRITE
to this
signal of the
images
is
finding. July
1992
Figure
5.
Images obtained 19 years after initial surgical resection from a man aged 41 years with a recurrent chondrosarcoma (conventional 1). (a) Long TR/TE (2,500/90) axial MR image obtained at 1.5 T shows a large tumor with heterogeneous signal intensity centered at the petrooccipital junction (arrow). (b) Axial CT scan shows that the tumor contains prominent chondroid mineralization (arrow), which corresponds in location to areas of signal hypointensity on a. (c) Coronal CT scan shows the location of the petrooccipital synchondrosis (arrow) in relation to the tumor. type,
grade
vious
small
studies
sarcomas
clinical site
of cranial
reported
MR
of
imaging,
tumor
chondro-
before
the
the
was
the
advent
most
of
frequent
parasellar
region;
the next most frequent, the region of the cerebellopontine angle (5). Cranial chondrosarcomas within
almost
the
believed chondral
base;
In
our
center
cipital
study,
points
sphenooccipital
located drosis,
in
of the tumors
10
patients
of chondrosarimages was seen
(59%),
it corresponded
of prominent tion depicted other cases,
trix mineralization the 15 conventional tion
with
was
CT.
No
depicted
position
most patients, throughout erogeneous images
fibrocartilagitumors. Ma-
matrix
with
mineraliza-
CT in the single
characteristics
in was
intensity
observed
sigto
without matrix mineralization. The nal characteristics of chondrosarcomas of the skull base are similar to those
sig-
within
the
to fatty
marrow
defined
on postcontrast
appendicular
on
skeleton
how
To our
knowledge,
the characteristics
of skull-base
chondrosarcomas
hanced
with
gadolinium
Volume
184
#{149} Number
en-
have 1
not been
delay
of contrast
aging
might
affect
cartilaginous
bone,
or
ally
contain
adminis-
tissues
of radiation
degeneration
such
as osteochondromas
extent,
do
(1,2,5,6,13).
usu-
exposure of benign
or malig(3,13).
In
pre-
at
and
diagnostic
con-
have
of
Most
off-midline
the
chondrocenter
points,
long
TR/TE
MR images
(4,16).
subgroups
of
The
range
of T2 values
mas
in our
study
ported
in both
(16,17).
These
relaxation
overlapped
chordoma findings
parameters times
those
re-
subgroups suggest that such
have
chordomas.
of chondrosarco-
as Ti
limited
and
useful-
in the distinction between the two types of skull-base tumors. Whenever present, prominent chondroid-type mineralization occurs within chondrosarcomas and not within the chordomas ness
as
lesions
the other
rests
whereas most chordomas are located in the midline (16). Both tumors can have very high signal intensity on unen-
T2
In ad-
can develop
that
likely
chondrosarconlas
is chordoma.
quantitative
not
and
base
differential
conventional im-
endochondral
that
cartilage
nant
MR
suture
Sze et al (17) reported that calculated Ti and T2 relaxation times could be used to distinguish between the chondroid and
after adminlt is therefore and
base
skull
was
suggest
cartilaginous
with
hanced
All study
enhancement. can arise directly
chondrosarcomas
a result
skull
less well
degree,
one
synchondrosis
main
sarcomas
images.
tissue,
other
to
images
between the
The
four other near the
synchonsynchondro-
findings
of the from
sideration
next
in our
material
pattern of tumor Chondrosarcomas
dition,
(15).
images
tumors
petrooccipital synchondroses.
mar-
generally
These
originate
paren-
MR
the petrooc-
synchondrosis,
vomer.
is
17 lesions
Of the points
at the sphenoethmoid and one was at the
these
tissue
margins
MR
MR
tration
from
lo-
were
unenhanced
unknown
and
brain
tumor
obtained immediately of gadolinium.
istration
tumor enhanced
than
However,
were
and those single de-
differentiated chondrosarcoma had nal characteristics generally similar those of conventional chondrosarconlas
cated
degree
chyma.
In
in a hetMR
neural
rosarcomas
postcontrast
between
or residual tumors before surgery. The
a greater
the
was seen
define
to adjacent
chond
than
MR signal
helped
relative
because
of
enhancement
13 of
at or near
sis of the sphenoethrnoidal
Chondrosarcomas
most of each tumor pattern. Postcontrast often
gins
chondrosarcoma.
difference
recurrent imaged
to the
was seen in seven chondrosarcomas
dedifferentiated No
in seven
reported.
showed a marked degree of contrast enhancement in nearly all patients.
coarse matrix nlineralizaon CT scans. In three the signal heterogeneity
was caused by prominent nous elements within the
imaged
and
previously
occur
occurrence
to the endobone structures
synchondrosis. two had center
lesions,
Signal heterogeneity comas on long TR/TE
always this
to be secondary origin of these
(5,6,13).
had
skull
Radiology
#{149} 107
reported
in the radiology
literature
tients
(4,16,18). Differentiation between chordoma and chondrosarcoma is often based on histologic analysis and immu-
nohistochemical staining. cific for ectoderm-derived as epithelial
atins,
membrane
are
positive
in chordomas
cases,
and
not
chondrosarcomas
(10,13). Other common also be included in the nosis with chondrosarcomas
and
spesuch and ker-
antigen
in mesoderm-derived
gioma
Markers tumors,
metastatic
differentiation
tumors that can differential diagare menin-
lesions.
In many
of these
diagnostic
entities that is based solely on MR imaging and CT characteristics may be impossible.
However,
a heterogeneously
enhanced tumor located at the petrooccipital synchondrosis that has high signal intensity on long TR/TE images, contains chondroid mineralization, and is associated with erosive bone changes strongly favors the diagnosis of chondrosarcoma. Gross total resection of tumor has
been
reported
treatment
skull
to be the most
for
chondrosarcomas
base
(8,19,20).
It is crucial
the extent
of these
tumors
select the best surgical resection of as much (8,19,20). MR imaging
effective of the to define
in order
to
approaches for tumor as possible has been reported
to be superior to CT for evaluation of the extent of skull-base neoplasms because it has greater contrast resolution and because beam-hardening artifacts affect CT (4,8). However, CT was proved superior to MR imaging in detection of tumorous mineralization and bone erosion (4). Surgeons
imaging tween normal (8,19,20).
near
at our
institution
use
MR
to define
the relationship beextension of tumor to adjacent soft tissues and blood vessels Resection
the internal
cause permanent (8). To determine risk for neurologic
of chondrosarcomas
carotid
artery
can
occlusion of this vessel which patients are at injury due to perma-
nent arterial occlusion, occlusion of the internal carotid artery with the intraluminal balloon test is generally performed in conjunction with clinical evaluation
and
imaging
of cerebral
blood flow by means of CT scans enhanced with stable xenon (8,21). Pa-
at risk
reduced
for
neurologic
cerebral
dergo
blood
placement
injury
flow
of arterial
bypass
grafts to obviate this complication In addition to MR imaging and test occlusion studies, CT scans ally
obtained
to ascertain
2.
from
can un-
the
(8,21). balloon are usu-
extent
are
regionally
invasive
4.
of 5.
tumorous invasion of bone (8). MR imaging showed that chondrosarcomas
3.
tumors.
It
showed frequent tumor extension into the cavernous sinus, sella turcica, sphenoidal sinus, and parapharyngeal space. Development of new surgical ap-
6.
proaches
8.
to the
skull
base
has
7.
facilitated
radical resection of tumor (8,19,20). For resection of chondrosarcomas that invade the civus and extend into sphenoidal and ethmoidal sinuses, the basal subfrontal
approach
is an effective
tech-
sions
However, tumorous extenlateral to the petrous internal ca-
rotid
artery
nique
9.
10.
(8).
cannot
be reached
with
I I.
this
method (8,19). For these tumors, the subtemporal and preauricular infratemporal approach can be used (8,19,20). Whenever
and and the
chondrosarcomas
are
invade the civus, petrous sphenoidal and ethmoidal subfrontal
poral
transbasal
approaches
(8,19,20).
12.
large
13.
bone, sinuses,
and
diagnosis,
infratem-
14.
are combined
In many
cases,
removal
of tu-
mor with these methods can be performed extradurally (8,19,20). However, whenever chondrosarcomas invade the
15.
superior into the
16.
sinus,
sphenoidal suprasellar
or both,
used
to supplement
an
civus cistern,
and extend cavernous
intradural
the
approach
main
is
extradural
part of the procedure (8,19,20). Gross total tumor resection and adjuvant, precision, high-dose radiation therapy for residual tumors after surgical debulking have produced encouraging preliminary results (9,22). Determination of the efficacy
of these
methods
in the
cure
long-term control of chondrosarcomas will require adequate follow-up (8).
Pritchard Di, Lunke RJ, Taylor WF, Dahlin DC, Medley BE. Chondrosarcoma: a clinicopathologic and statistical analysis. Cancer 1980; 45: 149-157. Dahlin DC, Unni KK. Chondrosarcomas. In: Bone tumors. 4th ed. Springfield, Ill: Thomas, 1986; 227-268. Oot RF, Melville GE, New PFJ, et al. The role of MR and CT in evaluating clival chordomas and chondrosarcomas. AIR 1988; 151:567-575. Grossman RI, Davis KR. Cranial computed tomographic appearance of chondrosarcoma of the base of the skull. Radiology 1981; 141: 403-408. Bahr AL, Gayler BW. Cranial chondrosarcomas. Radiology 1977; 124:151-156. Cianfrigiia F,Pompili A, Occhipinti E. Intracranial malignant cartilaginous tumors: report of two cases and review of literature. Acta Neurochir 1978; 45:163-175. Sen CN, Sekhar UN, Schramm VL,Janecka IP. Chordoma and chondrosarcoma of the cranial base: an 8-year experience. Neurosurgery 1989; 25:931-941. Suit HO, Goitein M, Munzenrider J, et al. Definitive radiation therapy for chordoma and chondrosarcoma of base of skull and cervical spine. J Neurosurg 1982; 56:377-385. Barnes U. Pathobiology of selected tumors of the base of the skull. Skull Base Surg 1991; 1:207-216. Lee YY, Van Tassel P. Craniofacial chondrosarcomas: imaging findings in 15 untreated cases. AJNR 1989; 10:165-470. Evans HU, Ayala AG, Romsdahl MM. Prognostic factors in chondrosarcoma of bone: a clinicopathologic analysis with emphasis on histologic grading. Cancer 1977; 40:818-831. Huvos AG. Chondrosarcomas of the craniofacial bones. In: Mitchell J, ed. Bone tumors:
or
17. 18. 19.
ral-infratemporal
20. U 21.
Acknowledgments: The authors thank Douglas Kondziolka, MD, and L. Dade Lunsford, MD, for contributing case materials, and Kathryn Frazier for assistance in the preparation of our
manuscript.
treatment
and
prognosis.
2nd
approach
to extensive
cra-
nial base tumours. Acta Neurochir (Wein) 1988; 92:83-92. Sekhar UN, Schramm VU Jr,Jones NF. Subtemporal-preauricular infratemporal fossa approach to large lateral and posterior cranial base neoplasms. J Neurosurg 1987; 67:488-499. Erba
SM,
Horton
JA, Latchaw
RE, et at.
loon test occlusion of the internal carotid tery with xenon/CT cerebral blood flow ing. AJNR 1988; 9:35-38. 22.
ed.
Philadelphia: Saunders, 1991; 395-401. Som Ph’!, Dillon WP, Sze G, Lidov M, Biller HF, Lawson W. Benign and malignant sinonasal lesions with intracranial extension: differentiahon with MR imaging. Radiology 1989; 172: 763-766. Golifieri R, Baddeley H, PringleJS. Primary bone tumors: MR morphologic appearance correlated with pathologic examinations. Acta Radiol 1991; 32:290-298. Meyers SP, Hirsch WLJr, Curtin HD, Barnes U, Sekhar UN, Sen C. Magnetic resonance imaging features of chordomas of the skull base. AJNR (in press). Sze G, Uichanco US III, Brant-Zawadzki MN, et at. Chordomas: MR imaging. Radiology 1988; 166:187-191. Meyer JE, Oot RF, Lindfors KF. CT appearance of cival chordomas. J Comput Assist Tomogr 1986; 10:34-38. Sekhar UN, Janecka IP, Jones NF. Subtempo-
Austin-Seymour
M, Munzenrider
Bat-
arimag-
j, Goitein
M,
et at. Fractionated proton radiation therapy of chordoma and low-grade chondrosarcoma of the base of the skull. J Neurosurg 1989; 70: 13-17.
References 1.
Russell OS, Rubinstein U. Chondrosarcomas and chordomas. In: Russell OS, Rubinstein U, eds. Pathology of tumours of the nervous system. Baltimore: Williams & Wilkins, 1989; 819821.
108
#{149} Radiology
July 1992
