Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology
Department , Zagazig University Hospitals
Egypt
FINR (Fellowship of Interventional
Neuroradiology)-Switzerland [email protected]
Knowing as much as
possible about your enemy
precedes successful battle
and learning about the
disease process precedes
successful management
Pineal Region Masses
a) Intrinsic Pineal Mass
b) Extrinsic Pineal Mass
The pineal gland is located in the midline at the level of the midbrain , it is
situated between the thalami at the posterior aspect of the 3
rd
ventricle ,
the internal cerebral veins and vein of Galen are located superior &
posterior to the pineal gland respectively
A-Genu of the
Corpus Callosum
B-Anterior Horn of
the Lateral Ventricle
C-Internal Capsule
D-Thalamus
E-Pineal Gland
F-Choroid Plexus
G-Straight Sinus
Normal Pineal gland
Normal pineal anatomy , sagittal T1 shows the normal anatomy of the pineal
region , the pineal gland (arrow) lies below the splenium of the corpus
callosum , the flow void from the vein of Galen crosses just above the
pineal gland , the tectal plate is located immediately inferior to the gland
a) Intrinsic Pineal Mass :
1-Benign Cyst
2-Germ Cell Tumors
3-Parenchymal Cell Tumors
4-Metastases
1-Benign Cyst :
a) Incidence
b) Radiographic Features
c) Differential Diagnosis
a) Incidence :
-Pineal cysts are typically found in young aged
adults (20-30 years of age) more in women
-Simple cystic structure within the gland
measuring < 1.5 cm
-Unlikely to be significant when no mass effect
and when there are no relevant symptoms
b) Radiographic Features :
*CT :
-Well circumscribed fluid density lesions with
thin rim calcification seen in 25%
-Some peripheral enhancement is also often
seen
-The internal cerebral veins are elevated and
splayed by the cyst
*MRI :
-Slightly higher signal than CSF on all sequences
-A common incidental finding on MRI studies
*T1 :
-Typically iso to low signal compared to brain
parenchyma
-55 to 60% are somewhat hyperintense when
compared to CSF
-Generally homogenous signal
*T2 :
-High signal
-Usually slightly hypointense to CSF
*T1+C :
-Approximately 60% of lesions enhance
-Enhancement is usually thin (< 2mm) and confined
to the rim (either complete or incomplete)
-It is important to note that if post contrast imaging
is delayed (60 - 90min), gadolinium may diffuse
into the cyst fluid and may lead to the mass
appearing solid
-In atypical cases enhancement may be nodular or
there may be evidence of previous hemorrhage
into the cysts
a) Sagittal T1+C shows an
oval , low signal intensity ,
20mm lesion in the pineal
region , a finding
consistent with a cyst , the
lesion has a thin
incomplete enhancing rim
(arrow) , no nodularity of
the wall and no associated
hydrocephalus are seen
b) Axial T2 shows an oval
hyperintense lesion similar
to CSF (arrow) in the
pineal region
c) Axial FLAIR image shows
that the signal of the lesion
(arrow) is not completely
suppressed due to the
proteinaceous contents
T1+C shows a round low signal intensity 8 mm lesion in the
pineal region , a finding consistent with a cyst , the lesion has
a thin incomplete enhancing rim (arrow) , no nodularity of the
wall and no associated hydrocephalus are seen
c) Differential Diagnosis :
-A differential consideration is Pineocytoma
which would shows internal enhancement and
may have cystic component, however a truly
cystic Pineocytoma is considered very rare
2-Germ Cell Tumors :
-Extragonadal germ cell tumors can be found in the
pineal gland as well as other intracranial and
extracranial midline locations including the
suprasellar region, mediastinum and sacrococcygeal
region
a) Germinoma (most common)
b) Teratoma
c) Embryonal Cell Carcinoma
d) Choriocarcinoma
a) Germinoma :
1-Incidence
2-Radiographic Features
3-Tumor Markers
1-Incidence :
-Most common pineal germ cell tumor (equivalent to
seminoma in testes and dysgerminoma in ovary)
-Males predominate (10:1), age 10 to 30 years
-In females, more commonly located in suprasellar location
-10% have synchronous infundibular / suprasellar
germinoma
-Serum markers (alpha-fetoprotein) may also be
positive
-Sensitive to radiation therapy
2-Radiographic Features :
a) CT
-Well defined slightly hyperdense mass that
engulfs a prominent calcified pineal gland
-Homogeneous intense enhancement
-Central calcification due to pineal engulfment
(rare)
Axial nonenhanced CT shows a hyperattenuating lesion in the
pineal region that has engulfed the pineal calcification (arrow)
Nonenhanced CT shows a partly calcified mass in the pineal
region (arrow)
CT+C shows an enhancing mass in the pineal region which engulfs a
calcified pineal gland
The tumor contains calcifications , there is homogeneous
enhancement
b) MRI
-T1 : isointense or slightly hyperintense to adjacent
brain
-T2 : isointense or slightly hyperintense to adjacent
brain, may have areas of cyst formation, central
calcification appears low signal (engulfed pineal
gland)
-T1+C : vivid and homogeneous
-ADC : Low ADC (highly cellular)
-MRI helps delineate local seeding to ventricles and
distant seeding of the subarachnoid space (spinal
imaging is also required)
T1
T1+C
T1 T2
T1+C
Sagittal T2 shows a mass (black arrow) which is solid with small cysts , the tumor
extends upward , compressing and displacing the internal cerebral vein (white
arrows)
Axial T1+C shows a homogeneously enhancing mass in the pineal region
Sagittal T1+C demonstrates an enhancing mass in the pineal region ,
compression of the quadrigeminal plate and aqueduct is shown
Sagittal T1+C shows a mass which is solid with small cysts and marked
enhancement
Axial T1+C shows an enhancing mass in the pineal region with bilateral
extension into the posterior thalami
Suprasellar germinoma , sagittal T2 shows a solid mass with a cystic area ( arrow ) ,
The tumor extends upward toward the infundibular recess
Suprasellar germinoma , sagittal T1+C with fat saturation shows a solid mass with
marked enhancement , the pituitary gland is compressed and flattened along the
sellar floor (arrows) , the tumor extends upward toward the infundibular recess
**The following T1+C , Diffusion & T1+C show :
-Germinoma in a 19 years old man with headaches
(a) Sagittal postcontrast T1-weighted MR image shows a
lesion in the pineal region that homogeneously
enhances , note the associated mild hydrocephalus
(b) Diffusion-weighted MR image shows high signal
intensity in the lesion , a finding indicative of high
cellularity
(c) Sagittal gadolinium-enhanced T1-weighted MR image
shows nodular enhancing masses (arrows) along the
cauda equina , findings consistent with drop
metastases
Germinoma in a 19 years old man with headaches, (a) Sagittal T1+C shows a lesion in the pineal
region that homogeneously enhances, note the associated mild hydrocephalus, (b) Diffusion-
weighted MR shows high signal intensity in the lesion, a finding indicative of high cellularity,
(c) Sagittal T1+C shows nodular enhancing masses (arrows) along the cauda equina, findings
consistent with drop metastases
1-Incidence :
-Second most common pineal germ cell tumor
-Almost exclusively in male children
-The most common congenital intracranial
tumor and are usually diagnosed prenatally
-Presence of fat and calcification is
diagnostically helpful with little to no
enhancement
2-Radiographic Features :
*CT :
-Demonstrates at least some fat and some
calcification which is usually solid / clump like
-They usually have cystic and solid components,
contributing to an irregular outline, solid
components demonstrate variable
enhancement
CT without contrast , note heterogeneity due to multiple small
cysts and area of calcification on anterolateral rim
CT without contrast demonstrates a heterogeneous mass in the pineal region
extending anteriorly into the cistern of the velum interpositum , the mass contains
several large chunks of calcification and a darker cystic appearing are (arrow head)
, heterogeneity like this especially when there is lipid material and calcification is a
hallmark of mature teratoma
CT+C , there is relatively homogeneous enhancement of the non-calcified
solid portions of the tumor , the cystic region doesn’t enhance
*MRI :
-T1 :
-Hyperintense components due to fat and
proteinaceous / lipid rich fluid
-Intermediate components of soft tissue
-Hypointense components due to calcification and
blood products
-T2 :
-Mixed signal from differing components
-T1+C :
-Little or no enhancement
-Solid soft tissue components show enhancement
Pineal teratoma in a 2-year-old boy , Axial (a) and sagittal (b) T1 show
a large heterogeneous pineal gland mass (arrowheads) and severe
obstructive hydrocephalus
Axial T1 shows a lobulated , heterogeneous lesion that contains an area of
hyperintensity (arrow) , a finding consistent with fat
Sagittal T1 shows a lobulated mass in the pineal region with foci of T1
shortening due to fat and variable signal intensity related to calcification
Sagittal T1 shows grossly heterogeneous mass with large amounts of hyperintense lipid material ,
it extends anteriorly towards the cistern of velum interpositum and posterior 3
rd
ventricle ,
note the cystic region (*) , the signal void of internal cerebral veins (arrow head) is superior
to the mass , but there is a thin rim of hypointensity encircling the mass , suggesting a tumor
capsule
T1+C shows enhancement of the soft-tissue portions of the lesion
Ruptured pineal region dermoid
Ruptured pineal region teratoma , T1 shows multiple high signal intensity foci
corresponding to the lipid droplets
Ruptured pineal region teratoma , T1 & T2 show a supernatant lipid layer floating on the heavier
CSF in the superior portions of both lateral ventricles , on the T2 there are high and low
signal intensity bands at the lipid interfaces caused by a chemical shift artifact
Ruptured Dermoid cyst in a 16 year old girl with altered mental status , T1+C shows a hyperintense lesion
(arrowhead) projecting anterior to the splenium of the corpus callosum , the signal intensity of the lesion
did not change after administration of contrast material , Linear low-signal-intensity structures can be
seen within the lesion , a finding consistent with hair. Lipid-fluid levels are seen in the frontal horns of the
lateral ventricles (arrows)
3-Choriocarcinoma, Yolk Sac Tumors and
Embryonal Carcinoma :
-Are rare neoplasms
-These neoplasms may have imaging findings
similar to those of other germ cell neoplasms or
primary pineal neoplasms
-Evaluation of tumor markers assists in making the
appropriate diagnosis
-These lesions may also hemorrhage, resulting in T1
shortening
a) Sagittal T1 weighted MR
image shows an
heterogeneous pineal region
mass with foci of T1
shortening due to
hemorrhage , note the
associated hydrocephalus
b) Axial postcontrast T1-
weighted MR image shows
that the pineal region mass
also has an heterogeneous
enhancement with foci of
necrosis/cyst , involvement of
the tectal plate and both
thalami are also present (not
shown) , evaluation of serum
oncoproteins demonstrated
high level of b-hCG , biopsy of
the lesion revealed that it
corresponds to
Choriocarcinoma
3-Parenchymal Cell Tumors :
a) Pineocytoma
b) Pineoblastoma
a) Pineocytoma :
-No male predilection
-Older age group, mean age 35 years
-Slow growing, dissemination is uncommon
-No helpful imaging features, cannot be
distinguished by imaging features from a
Pineoblastoma
CT without contrast shows a large and relatively homogeneous mass in the pineal
region with peripheral displacement of pineal calcification (arrows) , the mass has
extended anteriorly along the velum interpositum , this is the exploded pineal
appearance that suggests an intrinsic pineal parenchymal neoplasm
Pineal apoplexy secondary to a pineocytoma , Axial nonenhanced CT shows a
hyperattenuating lesion with a posterior cystic component in the pineal region , there
is anterior displacement of the pineal calcifications , a hematocrit level is noted within
the cystic component (arrow) , a finding consistent with hemorrhage , hydrocephalus is
also present
CT+C shows homogenous enhancement of the mass which assumes a
triangular shape as it conforms to the contours of the pulvinar of
the thalami and velum interpositum
T1+C shows heterogenous enhancement is seen , anteriorly ,
there is non-enhanced cystic region (*)
T1
T1
T2
T1+C
Sagittal postcontrast T1 shows an avidly enhancing mass in the pineal region
with resultant hydrocephalus
b) Pineoblastoma :
-Highly malignant PNET (Primitive Neuroectodermal
Tumors)
-In patients with trilateral retinoblastoma, Pineoblastoma
may develop in patients with familial and or bilateral
retinoblastoma
-(Exploded calcifications) along outside of mass
(peripherally), unlike germinoma which engulfs and
induces calcification of the pineal gland
-Dense enhancement
-Larger, more heterogeneous with much greater
propensity for local invasion and CNS dissemination
Axial nonenhanced CT shows a large pineal region mass with resultant hydrocephalus ,
the pineal calcifications are exploded toward the periphery (arrows)
T1
T2
T1+C
Trilateral retinoblastoma
4-Metastases :
-Due to the lack of a blood brain barrier,
metastases to the pineal gland occur relatively
commonly but rarely in the absence of a
known malignancy
-Leptomeningeal disease is present in 2/3 of
patients with pineal metastases
b) Extrinsic Pineal Mass :
1-Gliomas
2-Vein of Galen Aneurysm
3-Meningioma
4-Quadrigeminal Plate Lipoma
1-Gliomas :
-Gliomas (most commonly astrocytomas) of
varying grade may occur in adjacent intra-axial
structures such as the tectum, midbrain or
splenium of the corpus callosum
Tectal Glioma :
a) Incidence
b) Radiographic Features
A-Anterior Horn of the
Lateral Ventricle
B-Caudate Nucleus
C-Anterior Limb of the
Internal Capsule
D-Putamen and Globus
Pallidus
E-Posterior Limb of the
Internal Capsule
F-Third Ventricle
G-Quadrigeminal Plate
Cistern (Tectal plate)
H-Cerebellar Vermis
I-Occipital Lobe
a) Incidence :
-Tectal plate gliomas are encountered in
children and adolescents
-Usually low grade tectal tumor causing
aqueduct stenosis
-Typically low grade astrocytoma with good
prognosis
b) Radiographic Features :
-CT :
-Typical CT finding is homogenous expansion of
tectal plate, isodense to grey matter with
minimal enhancement in postcontrast image
CT shows non-communicating hydrocephalus , note the low density lesion of
the tectal plate
-MRI :
-Typically the tumors demonstrate expansion of the
tectal plate by a solid nodule of tissue
*T1 :
-Iso to slightly hypointense to grey matter
*T2 :
-Hyperintense to grey matter
*T1+C :
-Usually no enhancement
-Higher grade tumors tend to be larger and tend to
enhance more vividly
T1
T1
T1
A, Sagittal T1 shows severe hydrocephalus with poor visualization of
aqueduct and nonenhancing isointense diffuse tectal mass
B, Sagittal T1 shows 5 years later after shunting shows stable tectal
lesion
T2
T2 FLAIR shows a tectal mass leading to obliteration of the
cerebral aqueduct
T1+C shows a slightly hypointense tectal mass which does not
enhance , the mass obstructs the aqueduct and is stable over
8 years
A, Sagittal T1+C shows nonenhancing tectal mass
B, 18 months later , sagittal T1+C shows an increase in size and
enhancement of the tectal mass , necessitating radiotherapy
T1+C
2-Vein of Galen Aneurysm :
-Despite the name, a vein of Galen aneurysm
isn’t a true aneurysm, instead, it represents
dilatation of the vein of Galen due to an
arteriovenous fistula between the anterior or
posterior circulation and the venous plexus
leading to the vein of Galen
3-Meningioma :
-The tentorial apex, adjacent to the pineal gland,
is a characteristic location for meningioma
-The tentorial meningioma tends to depress the
internal cerebral veins, in contrast to a pineal-
based mass which typically elevates the
internal cerebral veins
4-Quadrigeminal Plate Lipoma :
-At CT, lipomas have low attenuation, consistent
with fat
-At MR imaging, they have the same signal
characteristics as fat (hyperintense on T1 with
saturation on fat-saturated images)
-No enhancement is seen on postcontrast
images
Quadrigeminal plate lipoma , (a) axial T1 , (b) sagittal T1 show a lobulated ,
hyperintense mass of the quadrigeminal plate , note the associated
thinning of the posterior body (arrow) and splenium of the corpus
callosum